US Ecology (ECOL) 10-Q 11 May 20 2020 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2020	May 05, 2020
Document Information
Document Type	10-Q
Document Quarterly Report	true
Document Transition Report	false
Document Period End Date	Mar. 31, 2020
Entity File Number	001-39120
Entity Registrant Name	US ECOLOGY, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	84-2421185
Entity Address, Address Line One	101 S. Capitol Blvd., Suite 1000
Entity Address, City or Town	Boise
Entity Address, State or Province	ID
Entity Address, Postal Zip Code	83702
City Area Code	208
Local Phone Number	331-8400
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		31,503,073
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q1
Entity Central Index Key	0001783400
Amendment Flag	false
Common Stock
Document Information
Title of 12(b) Security	Common Stock
Trading Symbol	ECOL
Security Exchange Name	NASDAQ
Warrants
Document Information
Title of 12(b) Security	Warrants to Purchase Common Stock
Trading Symbol	ECOLW

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Current Assets:
Cash and cash equivalents	$ 109,790	$ 41,281
Receivables, net	240,378	255,310
Prepaid expenses and other current assets	27,080	25,136
Income taxes receivable	10,332	11,244
Total current assets	387,580	332,971
Property and equipment, net	485,325	478,768
Operating lease assets	55,843	57,396
Restricted cash and investments	5,168	5,069
Intangible assets, net	564,124	574,902
Goodwill	466,031	766,980
Other assets	14,568	15,158
Total assets	1,978,639	2,231,244
Current Liabilities:
Accounts payable	51,387	46,906
Deferred revenue	21,698	14,788
Accrued liabilities	50,245	65,869
Accrued salaries and benefits	22,069	29,653
Income taxes payable	1,324	726
Short-term borrowings	396
Current portion of long-term debt	3,358	3,359
Current portion of closure and post-closure obligations	2,704	2,152
Current portion of operating lease liabilities	17,813	17,317
Total current liabilities	170,994	180,770
Long-term debt	855,003	765,842
Long-term closure and post-closure obligations	84,392	84,231
Long-term operating lease liabilities	38,092	39,954
Other long-term liabilities	31,439	20,722
Deferred income taxes, net	122,396	128,345
Total liabilities	1,302,316	1,219,864
Commitments and contingencies (See Note 18)
Stockholders' Equity:
Common stock $0.01 par value per share, 50,000 authorized; 31,503 and 31,461 shares issued and outstanding, respectively	315	315
Additional paid-in capital	817,730	816,345
Retained (deficit) earnings	(97,179)	206,574
Treasury stock, at cost, 415 and 0 shares, respectively	(18,332)
Accumulated other comprehensive loss	(26,211)	(11,854)
Total stockholders' equity	676,323	1,011,380
Total liabilities and stockholders' equity	$ 1,978,639	$ 2,231,244

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares shares in Thousands	Mar. 31, 2020	Dec. 31, 2019
CONSOLIDATED BALANCE SHEETS
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	50,000	50,000
Common stock, shares issued	31,503	31,461
Common stock, shares outstanding	31,503	31,461
Treasury stock, shares	415	0

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
CONSOLIDATED STATEMENTS OF OPERATIONS
Revenue	$ 240,720	$ 131,037
Direct operating costs	179,598	95,796
Gross profit	61,122	35,241
Selling, general and administrative expenses	51,058	20,305
Goodwill impairment charges	300,300
Operating (loss) income	(290,236)	14,936
Other income (expense):
Interest income	89	207
Interest expense	(9,310)	(4,030)
Foreign currency gain (loss)	937	(139)
Other	171	110
Total other expense	(8,113)	(3,852)
(Loss) income before income taxes	(298,349)	11,084
Income tax (benefit) expense	(263)	3,041
Net (loss) income	$ (298,086)	$ 8,043
(Loss) earnings per share:
Basic (in dollars per share)	$ (9.52)	$ 0.37
Diluted (in dollars per share)	$ (9.52)	$ 0.36
Shares used in (loss) earnings per share calculation:
Basic (in shares)	31,305	21,987
Diluted (in shares)	31,305	22,197

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME
Net (loss) income	$ (298,086)	$ 8,043
Other comprehensive income (loss):
Foreign currency translation (loss) gain	(8,259)	1,689
Net changes in interest rate hedge, net of taxes of $(1,654) and ($184), respectively	(6,098)	(691)
Comprehensive (loss) income, net of tax	$ (312,443)	$ 9,041

CONSOLIDATED STATEMENTS OF CO_2

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Other comprehensive income (loss):
Net changes in interest rate hedge, tax	$ (1,621)	$ (184)

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Cash flows from operating activities:
Net (loss) income	$ (298,086)	$ 8,043
Adjustments to reconcile net (loss) income to net cash provided by operating activities
Depreciation and amortization of property and equipment	17,978	8,125
Amortization of intangible assets	9,441	2,811
Accretion of closure and post-closure obligations	1,266	1,125
Property and equipment impairment charges		25
Goodwill impairment charges	300,300
Unrealized foreign currency loss (gain)	2,703	(371)
Deferred income taxes	(3,320)	2,905
Share-based compensation expense	1,564	1,222
Share-based payments of business development and integration expenses	181
Unrecognized tax benefits	52	131
Net loss (gain) on disposition of assets	184	(272)
Gain on insurance proceeds from damaged property and equipment		(4,653)
Amortization and write-off of debt issuance costs	298	204
Amortization and write-off of debt discount	245
Change in fair value of contingent consideration	(1,127)
Changes in assets and liabilities (net of effects of business acquisitions):
Receivables	13,467	16,577
Income taxes receivable	893	(1,487)
Other assets	(2,957)	525
Accounts payable and accrued liabilities	(13,618)	(11,935)
Deferred revenue	7,083	(47)
Accrued salaries and benefits	(7,446)	(3,417)
Income taxes payable	662	(517)
Closure and post-closure obligations	(417)	(470)
Net cash provided by operating activities	29,346	18,524
Cash flows from investing activities:
Business acquisitions (net of cash acquired)	(3,309)
Purchases of property and equipment	(19,131)	(7,223)
Insurance proceeds from damaged property and equipment		5,000
Proceeds from sale of property and equipment	781	459
Purchases of restricted investments	(56)	(23)
Net cash used in investing activities	(21,715)	(1,787)
Cash flows from financing activities:
Proceeds from long-term debt	90,000
Payments on long-term debt	(1,125)	(30,000)
Payments on short-term borrowings	(49,871)	(4,331)
Proceeds from short-term borrowings	50,267	6,449
Repurchase of common stock	(18,332)	(915)
Dividends paid	(5,667)	(3,970)
Payment of equipment financing obligations	(1,525)	(199)
Net cash provided by (used in) financing activities	63,747	(32,966)
Effect of foreign exchange rate changes on cash	(2,825)	393
Increase (decrease) in Cash and cash equivalents and restricted cash	68,553	(15,836)
Cash and cash equivalents and restricted cash at beginning of period	42,140	32,753
Cash and cash equivalents and restricted cash at end of period	110,693	16,917
Supplemental Disclosures:
Income taxes paid, net of receipts	1,241	2,085
Interest paid	7,642	3,462
Non-cash investing and financing activities:
Capital expenditures in accounts payable	$ 3,531	$ 912

CONSOLIDATED STATEMENTS OF CA_2

CONSOLIDATED STATEMENTS OF CASH FLOWS - (Restricted cash and investments) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
Reconciliation of Cash and cash equivalents and restricted cash
Cash and cash equivalents	$ 109,790	$ 41,281	$ 16,120	$ 31,969
Restricted cash	903	859	797	784
Cash and cash equivalents and restricted cash	$ 110,693	$ 42,140	$ 16,917	$ 32,753

CONSOLIDATED STATEMENTS OF STOC

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Common Stock	Additional Paid-In Capital	Retained (Deficit) Earnings	Treasury Stock	Accumulated Other Comprehensive Income (Loss)	Total
Beginning balances at Dec. 31, 2018	$ 220	$ 183,834	$ 189,324	$ (370)	$ (13,791)	$ 359,217
Increase (Decrease) in Stockholders' Equity
Net (loss) income			8,043			8,043
Other comprehensive (loss) income					998
Share-based compensation		1,222
Stock option exercised and issuance of common stock and restricted common stock	1	(1,103)
Dividends paid			(3,970)
Repurchase of common stock				(916)
Ending balances at Mar. 31, 2019	221	183,953	193,397	(1,286)	(12,793)	363,492
Beginning balances at Dec. 31, 2019	315	816,345	206,574		(11,854)	$ 1,011,380
Balance (in shares) at Dec. 31, 2019						31,461
Increase (Decrease) in Stockholders' Equity
Net (loss) income			(298,086)			$ (298,086)
Other comprehensive (loss) income					(14,357)
Share-based compensation		1,564
Stock option exercised and issuance of common stock and restricted common stock		(360)
Dividends paid			(5,667)
Share-based payments of business development and integration expenses		181
Repurchase of common stock				(18,332)
Ending balances at Mar. 31, 2020	$ 315	$ 817,730	$ (97,179)	$ (18,332)	$ (26,211)	$ 676,323
Balance (in shares) at Mar. 31, 2020						31,503

GENERAL

GENERAL	3 Months Ended
	Mar. 31, 2020
GENERAL
GENERAL	NOTE 1. GENERAL ​ Basis of Presentation ​ The accompanying unaudited consolidated financial statements include the results of operations, financial position and cash flows of US Ecology, Inc. and its wholly-owned subsidiaries. All inter-company balances have been eliminated. Throughout these consolidated financial statements words such as “we,” “us,” “our,” “US Ecology” and “the Company” refer to US Ecology, Inc. and its subsidiaries. ​ In the opinion of management, the accompanying unaudited consolidated financial statements include all adjustments (consisting only of normal recurring adjustments) necessary to present fairly, in all material respects, the results of the Company for the periods presented. These consolidated financial statements have been prepared by the Company pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”). Certain information and footnote disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States (“GAAP”) have been omitted pursuant to the rules and regulations of the SEC. These consolidated financial statements should be read in conjunction with the consolidated financial statements and accompanying notes included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2019. The results of operations for the three months ended March 31, 2020 are not necessarily indicative of the results to be expected for the entire year ending December 31, 2020. ​ The Company’s consolidated balance sheet as of December 31, 2019 has been derived from the Company’s audited consolidated balance sheet as of that date. ​ Use of Estimates ​ The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the financial statements, as well as the reported amounts of revenue and expenses during the reporting period. Actual results could differ materially from the estimates and assumptions that we use in the preparation of our consolidated financial statements. As it relates to estimates and assumptions in amortization rates and environmental obligations, significant engineering, operations and accounting judgments are required. We review these estimates and assumptions no less than annually. In many circumstances, the ultimate outcome of these estimates and assumptions will not be known for decades into the future. Actual results could differ materially from these estimates and assumptions due to changes in applicable regulations, changes in future operational plans and inherent imprecision associated with estimating environmental impacts far into the future. ​ Recently Issued Accounting Pronouncements ​ In December 2019, the FASB issued ASU No. 2019-12, “Income Taxes” (Topic 740): Simplifying the Accounting for Income Taxes (“ASU 2019-12”), which is intended to simplify various aspects related to accounting for income taxes. ASU 2019-12 removes certain exceptions to the general principles in Topic 740 and also clarifies and amends existing guidance to improve consistent application. This guidance is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2020, with early adoption permitted. The Company is currently evaluating the impact of this standard on its consolidated financial statements and related disclosures. In June 2016, the FASB issued ASU No. 2016-13, “Financial Instruments - Credit Losses” (Topic 326), which became effective for reporting periods beginning after December 15, 2019. The standard replaced the incurred loss impairment methodology under current GAAP with a methodology that reflects expected credit losses and requires the use of a forward-looking expected credit loss model for accounts receivables, loans, and other financial instruments. The standard requires a modified retrospective approach through a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period in which the guidance is effective. The Company adopted the new credit loss standard effective January 1, 2020 and the impact of the adoption was not material to the Company's consolidated financial statements as credit losses are not expected to be significant based on historical collection trends, the financial condition of payment partners, and external market factors. The Company will continue to actively monitor the impact of the recent coronavirus (‘COVID-19”) pandemic on expected credit losses. ​

REVENUES

REVENUES	3 Months Ended
	Mar. 31, 2020
REVENUES
REVENUES	NOTE 2. REVENUES ​ Our operations are managed in two reportable segments, Environmental Services and Field & Industrial Services, reflecting our internal reporting structure and nature of services offered. See Note 17 for additional information on our operating segments. ​ The following table presents our revenue disaggregated by our reportable segments and service lines: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, 2020 ​ ​ ​ ​ Field & ​ ​ ​ ​ ​ Environmental ​ Industrial ​ ​ ​ $s in thousands Services Services Total Treatment & Disposal Revenue (1) ​ $ 100,049 ​ $ 9,984 ​ $ 110,033 Services Revenue: ​ ​ ​ ​ ​ ​ ​ ​ ​ Transportation and Logistics (2) ​ ​ 26,696 ​ ​ 6,154 ​ ​ 32,850 Industrial Services (3) ​ ​ — ​ ​ 28,478 ​ ​ 28,478 Small Quantity Generation (4) ​ ​ — ​ ​ 11,084 ​ ​ 11,084 Total Waste Management (5) ​ ​ — ​ ​ 8,482 ​ ​ 8,482 Remediation (6) ​ ​ — ​ ​ 10,441 ​ ​ 10,441 Emergency Response (7) ​ ​ — ​ ​ 24,922 ​ ​ 24,922 Domestic Standby Services (8) ​ ​ — ​ ​ 9,467 ​ ​ 9,467 Other (9) ​ ​ — ​ ​ 4,963 ​ ​ 4,963 Revenue ​ $ 126,745 ​ $ 113,975 ​ $ 240,720 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, 2019 ​ ​ ​ ​ Field & ​ ​ ​ ​ ​ Environmental ​ Industrial ​ ​ ​ $s in thousands Services Services Total Treatment & Disposal Revenue (1) ​ $ 77,713 ​ $ 2,796 ​ $ 80,509 Services Revenue: ​ ​ ​ ​ ​ ​ ​ ​ ​ Transportation and Logistics (2) ​ ​ 14,619 ​ ​ 7,093 ​ ​ 21,712 Industrial Services (3) ​ ​ — ​ ​ 6,016 ​ ​ 6,016 Small Quantity Generation (4) ​ ​ — ​ ​ 8,189 ​ ​ 8,189 Total Waste Management (5) ​ ​ — ​ ​ 8,714 ​ ​ 8,714 Remediation (6) ​ ​ — ​ ​ 1,726 ​ ​ 1,726 Emergency Response (7) ​ ​ — ​ ​ 3,046 ​ ​ 3,046 Other (9) ​ ​ — ​ ​ 1,125 ​ ​ 1,125 Revenue ​ $ 92,332 ​ $ 38,705 ​ $ 131,037 (1) We categorize our treatment and disposal revenue as either “Base Business” or “Event Business” based on the underlying nature of the revenue source. We define Event Business as non-recurring projects that are expected to equal or exceed 1,000 tons, with Base Business defined as all other business not meeting the definition of Event Business. For the three months ended March 31, 2020 and 2019, 25% and 15% , respectively, of our treatment and disposal revenue was derived from Event Business projects. Base Business revenue accounted for 75% and 85% of our treatment and disposal revenue for the three months ended March 31, 2020 and 2019, respectively. (2) Includes collection and transportation of non-hazardous and hazardous waste. (3) Includes industrial cleaning and maintenance for refineries, chemical plants, steel and automotive plants, marine terminals and refinery services such as tank cleaning and temporary storage. (4) Includes retail services, laboratory packing, less-than-truck-load service and household hazardous waste collection. Contracts for Small Quantity Generation may extend beyond one year and a portion of the transaction price can be fixed. (5) Through our total waste management (“TWM”) program, customers outsource the management of their waste compliance program to us, allowing us to organize and coordinate their waste management disposal activities and environmental compliance. TWM contracts may extend beyond one year and a portion of the transaction price can be fixed. (6) Includes site assessment, onsite treatment, project management and remedial action planning and execution. Contracts for Remediation may extend beyond one year and a portion of the transaction price can be fixed. (7) Includes spill response, waste analysis and treatment and disposal planning. (8) We provide government-mandated, commercial standby oil spill compliance solutions to companies that store, transport, produce or handle petroleum and certain nonpetroleum oils on or near U.S. waters. Our standby services customers pay annual retainer fees under long-term or evergreen contracts for access to our regulatory certifications, specialized assets and highly trained personnel. When a customer with a retainer contract experiences a spill incident, we coordinate and manage the spill response, which results in incremental revenue for the services provided, in addition to the retainer fees. (9) Includes equipment rental and other miscellaneous services. ​ We provide services primarily in the United States, Canada and the Europe, Middle East, and Africa (“EMEA”) region. The following table presents our revenue disaggregated by our reportable segments and geographic location where the underlying services were performed: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, 2020 ​ Three Months Ended March 31, 2019 ​ ​ ​ ​ Field & ​ ​ ​ ​ ​ ​ Field & ​ ​ ​ ​ ​ Environmental ​ Industrial ​ ​ ​ ​ Environmental ​ Industrial ​ ​ ​ $s in thousands Services Services Total Services Services Total United States ​ $ 107,928 ​ $ 105,546 ​ $ 213,474 ​ $ 77,359 ​ $ 38,705 ​ $ 116,064 Canada ​ ​ 18,817 ​ ​ 1,077 ​ ​ 19,894 ​ ​ 14,973 ​ ​ — ​ ​ 14,973 EMEA ​ ​ — ​ ​ 5,239 ​ ​ 5,239 ​ ​ — ​ ​ — ​ ​ — Other (1) ​ — ​ 2,113 ​ 2,113 ​ — ​ — ​ — Total revenue ​ $ 126,745 ​ $ 113,975 ​ $ 240,720 ​ $ 92,332 ​ $ 38,705 ​ $ 131,037 ​ (1) Includes Mexico, Asia Pacific, and Latin America and Caribbean geographical regions. ​ Deferred Revenue We record deferred revenue when cash payments are received, or advance billings are charged, prior to performance of services, such as waste that has been received but not yet treated or disposed, and is recognized when these services are performed. During the three months ended March 31, 2020 and 2019, we recognized $8.4 million and $7.5 million of revenue that was included in the deferred revenue balance at the beginning of each year, respectively. ​ Receivables ​ Our receivables include invoiced and unbilled amounts where the Company has an unconditional right to payment. ​ Principal versus Agent Considerations ​ The Company commonly contracts with third-parties to perform certain waste-related services that we have promised in our customer contracts. We consider ourselves the principal in these arrangements as we direct the timing, nature and pricing of the services ultimately provided by the third-party to the customer. ​ Costs to obtain a contract ​ The Company pays sales commissions to employees, which qualify as costs to obtain a contract. Sales commissions are expensed as incurred as the commissions are earned by the employee and paid by the Company over time as the related revenue is recognized. Other commissions and incremental costs to obtain a contract are not material. ​ Practical Expedients and Optional Exemptions ​ Our payment terms may vary based on type of service or customer; however, we do not adjust the promised amount of consideration in our contracts for the time value of money as payment terms extended to our customers do not exceed one year and are not considered a significant financing component in our contracts. ​ We do not disclose the value of unsatisfied performance obligations as contracts with an original expected length of more than one year and contracts for which we do not recognize revenue at the amount to which we have the right to invoice for services performed is insignificant and the aggregate amount of fixed consideration allocated to unsatisfied performance obligations is not material.

BUSINESS COMBINATIONS

BUSINESS COMBINATIONS	3 Months Ended
	Mar. 31, 2020
BUSINESS COMBINATIONS
BUSINESS COMBINATIONS	NOTE 3. BUSINESS COMBINATIONS ​ Acquisition of Impact Environmental Services, Inc. ​ On January 28, 2020, we acquired Impact Environmental Services, Inc., an industrial cleaning and environmental services company based in Romulus, Michigan for $3.3 million. The acquired operations are reported as part of our Field & Industrial Services segment, however, revenues, net income, earnings per share and total assets are not material to our consolidated financial position or results of operations. ​ We allocated the purchase price to the assets acquired and liabilities assumed based on estimates of the fair value at the date of the acquisition, resulting in $300,000 allocated to goodwill and $900,000 allocated to amortizing intangible assets (primarily customer relationships) to be amortized over a weighted average life of approximately 12 years. All of the goodwill recognized was assigned to our Field & Industrial Services segment and is expected to be deductible for income tax purposes over a 15-year amortization period. ​ NRC Group Holdings Corp. ​ On November 1, 2019, the Company completed its acquisition (the “NRC Merger”) of NRC Group Holdings Corp. (“NRC”), a provider of comprehensive environmental, compliance and waste management services to the marine and rail transportation, general industrial and energy industries. The addition of NRC’s substantial service network strengthened and expanded US Ecology’s suite of environmental services, including new energy waste disposal and service capabilities, and provided expanded opportunities to establish US Ecology as a leader in standby and emergency response services. ​ The total merger consideration was $1,024.8 million, comprised of the following: ​ ​ ​ ​ ​ ​ ​ November 1, $s in thousands 2019 Fair value of US Ecology common stock issued (1) ​ $ 581,101 Fair value of replacement warrants issued (2) ​ 44,858 Fair value of replacement restricted stock units issued (3) ​ 141 Fair value of replacement stock options (4) ​ 360 Repayment of NRC’s term loan and revolving credit facility ​ 398,373 Total merger consideration ​ $ 1,024,833 (1) The fair value of US Ecology common stock issued was calculated based on 9,337,949 shares of US Ecology common stock multiplied by the closing price of US Ecology common stock of $62.23 per share on October 31, 2019, the day immediately preceding the closing of the NRC Merger. (2) The fair value of replacement warrants issued was calculated based on 3,772,753 replacement warrants multiplied by the fair value per warrant of $11.89 . The fair value per warrant was based on the closing price of the replaced NRC warrants (NYSE: NRCG.WS) of $2.33 on October 31, 2019, the day immediately preceding the closing of the NRC Merger, divided by the exchange ratio of 0.196 pursuant to the Merger Agreement. (3) The fair value of replacement restricted stock units issued was calculated based on 118,239 replacement restricted stock units multiplied by the closing price of US Ecology common stock of $62.23 per share on October 31, 2019, the day immediately preceding the closing of the NRC Merger, further multiplied by the ratio of the precombination service period to the remaining vesting period, or approximately 1.9% . (4) The fair value of replacement stock options issued was calculated based on 29,400 replacement stock options multiplied by the fair value per option of $12.26 . The fair value per option was calculated using the Black-Scholes option pricing model, with the following weighted-average assumptions: strike price of $52.30 per option, dividend yield of 1.2% ; expected volatility of 28.9% ; average risk-free interest rate of 1.5% ; and an expected term of 1 year. The replacement stock options became fully vested at the merger date therefore the entire fair value is considered merger consideration. The payment of transaction fees and expenses and repayment of $398.4 million of NRC’s debt were funded using proceeds from a new $450.0 million seven-year term loan. See Note 11 for more information. We have recognized the assets and liabilities of NRC based on our preliminary estimates of their acquisition date fair values. The purchase price allocations are preliminary and subject to change. We continue to gather information relevant to our determination of the fair value of acquired assets and liabilities primarily related to, but not limited to, property and equipment, identifiable intangible assets and deferred income taxes. Any adjustments to the purchase price allocations are made as soon as practicable but no later than one year from the merger date. The following table summarizes the merger consideration and the preliminary fair value estimates of assets acquired and liabilities assumed, recognized at the merger date, with purchase price allocation adjustments since the preliminary purchase price allocation as previously disclosed as of December 31, 2019: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ ​ ​ March 31, $s in thousands 2019 Adjustments 2020 Current assets ​ $ 131,653 ​ $ — ​ $ 131,653 Property and equipment ​ ​ 197,045 ​ ​ — ​ ​ 197,045 Identifiable intangible assets ​ ​ 303,600 ​ ​ — ​ ​ 303,600 Other assets ​ ​ 41,687 ​ ​ — ​ ​ 41,687 Current liabilities ​ ​ (83,460) ​ ​ (1,215) ​ ​ (84,675) Deferred income tax liabilities ​ ​ (56,596) ​ ​ 194 ​ ​ (56,402) Other liabilities ​ ​ (57,581) ​ ​ — ​ ​ (57,581) Total identifiable net assets ​ ​ 476,348 ​ ​ (1,021) ​ ​ 475,327 Goodwill ​ ​ 548,485 ​ ​ 1,021 ​ ​ 549,506 Total purchase price ​ $ 1,024,833 ​ $ — ​ $ 1,024,833 ​ Purchase price allocation adjustments related primarily to the receipt of additional information regarding the fair values of accrued liabilities, deferred income taxes and residual goodwill. Goodwill of $549.5 million arising from the acquisition is primarily attributable to the assembled workforce of NRC and expected synergies from combining operations. $309.4 million of the goodwill recognized was allocated to our Environmental Services segment and $240.1 million of the goodwill recognized was allocated to Field & Industrial Services segment. We expect $33.3 million of the acquired goodwill to be deductible for income tax purposes. During the first quarter of 2020, management determined that the projected future cash flows of certain reporting units identified as part of the NRC Merger indicated that the fair value of the reporting units may be below their respective carrying amounts. Accordingly, we performed an interim assessment of each reporting unit’s goodwill as of March 31, 2020. Based on the results of this assessment, we recognized goodwill impairment charges of $283.6 million related to our Environmental Services segment and $16.7 million related to our Field & Industrial Services segment in the first quarter of 2020. Refer to Note 10 for additional information. ​ The preliminary fair value of identifiable intangible assets related to the acquisition of NRC by major intangible asset class and corresponding weighted average amortization period are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Average ​ ​ ​ ​ ​ Amortization $s in thousands Fair Value Period (Years) Amortizing intangible assets: ​ ​ ​ ​ ​ Customer relationships - noncontractual ​ $ 193,700 ​ 14 Customer relationships - contractual ​ ​ 34,400 ​ 7 Permits and licenses ​ ​ 8,700 ​ 16 Tradenames ​ ​ 6,100 ​ 2 Non-compete agreements ​ ​ 3,300 ​ 2 Total identified amortizing intangible assets ​ ​ 246,200 ​ ​ Non-amortizing intangible assets: ​ ​ ​ ​ ​ Permits and licenses ​ ​ 57,400 ​ n/a Total identified intangible assets ​ $ 303,600 ​ ​ ​ The following unaudited pro forma financial information presents the combined results of operations as if NRC had been combined with US Ecology as of January 1, 2019. The pro forma financial information includes the accounting effects of the business combination, including the amortization of intangible assets, depreciation of property, plant and equipment, and interest expense. The unaudited pro forma financial information is presented for informational purposes only and is not indicative of the results of operations that would have been achieved if the acquisition had taken place at the beginning of the periods presented, nor should it be taken as indication of our future consolidated results of operations. ​ ​ ​ ​ ​ ​ ​ (unaudited) ​ ​ Three Months Ended $s in thousands March 31, 2019 Pro forma combined: ​ ​ ​ Revenue ​ ​ 231,195 Net loss ​ ​ (2,857) ​ The amounts of revenue and operating loss from NRC included in the Company’s consolidated statements of operations for the three months ended March 31, 2020 were $86.6 million and $304.0 million, respectively. NRC Merger-related business development and integration expenses of $2.9 million are included in Selling, general and administrative expenses in the Company’s consolidated statements of operations for the three months ended March 31, 2020. W.I.S.E. Environmental Solutions Inc. ​ On August 1, 2019, we acquired 100% of the outstanding shares of W.I.S.E. Environmental Solutions Inc. (“US Ecology Sarnia”), an equipment rental and waste services company based in Sarnia, Ontario, Canada for 23.5 million Canadian dollars, which translated to $17.9 million at the time of transaction and was funded with borrowings under the Credit Agreement. US Ecology Sarnia is reported as part of our Field & Industrial Services segment. The Company assessed the revenues, net income, earnings per share and total assets of US Ecology Sarnia and concluded they are not material to our consolidated financial position or results of operations. As such, pro forma financial information has not been provided. ​ We allocated the purchase price to the assets acquired and liabilities assumed based on estimates of the fair value at the date of the acquisition, resulting in $7.7 million allocated to goodwill and $6.2 million allocated to intangible assets (primarily customer relationships) to be amortized over a weighted average life of approximately 14 years. The purchase price allocation is preliminary, as estimates and assumptions are subject to change as more information becomes available. ​ Goodwill of $7.7 million arising from the acquisition is attributable to the assembled workforce and the future economic benefits of synergies with our other regional facilities and expansion into new markets. All of the goodwill recognized was assigned to our Field & Industrial Services segment and is not expected to be deductible for income tax purposes.

ACCUMULATED OTHER COMPREHENSIVE

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)	3 Months Ended
	Mar. 31, 2020
ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS).
ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)	NOTE 4. ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) ​ Changes in accumulated other comprehensive income (loss) (“AOCI”) consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Foreign ​ Unrealized Gain ​ ​ ​ ​ ​ Currency ​ (Loss) on Interest ​ ​ ​ $s in thousands Translation Rate Hedge Total Balance at December 31, 2019 ​ $ (10,925) ​ $ (929) ​ $ (11,854) Other comprehensive loss before reclassifications, net of tax ​ (8,259) ​ (6,310) ​ (14,569) Amounts reclassified out of AOCI, net of tax (1) ​ — ​ 212 ​ 212 Other comprehensive loss, net ​ (8,259) ​ (6,098) ​ (14,357) Balance at March 31, 2020 ​ $ (19,184) ​ $ (7,027) ​ $ (26,211) (1) Before-tax reclassifications of $268,000 ($212,000 after-tax) for the three months ended March 31, 2020, were included in Interest expense in the Company’s consolidated statements of operations. Amounts relate to the Company’s interest rate swap which is designated as a cash flow hedge. Changes in fair value of the swap recognized in AOCI are reclassified to interest expense when hedged interest payments on the underlying long-term debt are made or, for terminated swap agreements, amortized to interest expense over the period from termination to original maturity. Amounts in AOCI expected to be reclassified to interest expense over the next 12 months total approximately $516,000 ($407,000 after-tax). ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Foreign ​ Unrealized Gain ​ ​ ​ ​ ​ Currency ​ (Loss) on Interest ​ ​ ​ $s in thousands Translation Rate Hedge Total Balance at December 31, 2018 ​ $ (14,697) ​ $ 906 ​ $ (13,791) Other comprehensive income (loss) before reclassifications, net of tax ​ 1,689 ​ (581) ​ 1,108 Amounts reclassified out of AOCI, net of tax (2) ​ — ​ (110) ​ (110) Other comprehensive income (loss), net ​ 1,689 ​ (691) ​ 998 Balance at March 31, 2019 ​ $ (13,008) ​ $ 215 ​ $ (12,793) (2) Before-tax reclassifications of $139,000 ($110,000 after-tax) for the three months ended March 31, 2019, were included as a reduction of Interest expense in the Company’s consolidated statements of operations. Amounts relate to the Company’s interest rate swap which is designated as a cash flow hedge. Changes in fair value of the swap recognized in AOCI are reclassified to interest expense when hedged interest payments on the underlying long-term debt are made.

CONCENTRATIONS AND CREDIT RISK

CONCENTRATIONS AND CREDIT RISK	3 Months Ended
	Mar. 31, 2020
CONCENTRATIONS AND CREDIT RISK
CONCENTRATIONS AND CREDIT RISK	NOTE 5. CONCENTRATIONS AND CREDIT RISK ​ Major Customers ​ No customer accounted for more than 10% of total revenue for the three months ended March 31, 2020 or 2019, respectively. No customer accounted for more than 10% of total trade receivables as of March 31, 2020 or December 31, 2019. ​ Credit Risk Concentration ​ We maintain most of our cash and cash equivalents with nationally recognized financial institutions. Substantially all balances are uninsured and are not used as collateral for other obligations. Concentrations of credit risk on accounts receivable are believed to be limited due to the number, diversification and character of the obligors and our credit evaluation process. Credit risk associated with a portion of the Company’s trade receivables is reduced by our ability to submit claims to the Oil Spill Liability Trust Fund (“OSLTF”) for reimbursement of unpaid customer receivables related to services regulated under the provisions of the Oil Pollution Act of 1990 (“OPA 90”). As of March 31, 2020, the Company did not have any trade receivables that are eligible for submission to the OSLTF for reimbursement. ​

RECEIVABLES

RECEIVABLES	3 Months Ended
	Mar. 31, 2020
RECEIVABLES
RECEIVABLES	NOTE 6. RECEIVABLES ​ Receivables consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, ​ December 31, $s in thousands ​ 2020 2019 Trade ​ $ 187,619 ​ $ 196,593 Unbilled revenue ​ 49,854 ​ 54,727 Other ​ 5,959 ​ 7,000 Total receivables ​ 243,432 ​ 258,320 Allowance for doubtful accounts ​ (3,054) ​ (3,010) Receivables, net ​ $ 240,378 ​ $ 255,310 ​

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS	3 Months Ended
	Mar. 31, 2020
FAIR VALUE MEASUREMENTS
FAIR VALUE MEASUREMENTS	NOTE 7. FAIR VALUE MEASUREMENTS ​ Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Assets and liabilities recorded at fair value are categorized using defined hierarchical levels directly related to the amount of subjectivity associated with the inputs to fair value measurements, as follows: ● Level 1 - Quoted prices in active markets for identical assets or liabilities; ● Level 2 - Inputs other than quoted prices included within Level 1 that are either directly or indirectly observable; ● Level 3 - Unobservable inputs in which little or no market activity exists, requiring an entity to develop its own assumptions that market participants would use to value the asset or liability. The Company’s financial instruments consist of cash and cash equivalents, accounts receivable, restricted cash and investments, accounts payable and accrued liabilities, debt, interest rate swap agreements and contingent consideration. The estimated fair value of cash and cash equivalents, accounts receivable, accounts payable and accrued liabilities approximate their carrying value due to the short-term nature of these instruments. On September 19, 2019, the Company invested $7.9 million in the preferred stock of a privately held company which is included in Other assets in the Company’s consolidated balance sheets. The investment does not have a readily determinable fair value therefore the investment is valued at cost, less impairment, plus or minus observable price changes of an identical or similar investment of the same issuer, if any. As of March 31, 2020, there have been no identified events or changes in circumstances that would indicate the cost method investment should be impaired nor have there been any observable price changes of an identical or similar investment of the same issuer. The Company estimates the fair value of its variable-rate debt using Level 2 inputs, such as interest rates, related terms and maturities of similar obligations. At March 31, 2020, the fair value of the Company’s variable rate term loan was estimated to be $433.2 million, and the carrying value of the Company’s variable-rate revolving credit facility approximates fair value due to the short-term nature of the interest rates. The Company estimates the fair value of its contingent consideration liabilities using Level 3 inputs, including both observable and unobservable inputs. As a result, unrealized gains and losses may include changes in fair value that are attributable to both observable (e.g., changes in market interest rates) and unobservable (e.g., changes in unobservable long-dated volatilities) inputs. The Company’s assets and liabilities measured at fair value on a recurring basis consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, 2020 ​ ​ Quoted Prices in ​ Other Observable ​ Unobservable ​ ​ ​ ​ ​ Active Markets ​ Inputs ​ Inputs ​ ​ ​ $s in thousands (Level 1) (Level 2) (Level 3) Total Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed-income securities (1) ​ $ 2,424 ​ $ 1,842 ​ $ — ​ $ 4,266 Money market funds (2) ​ ​ 60,394 ​ ​ — ​ ​ — ​ ​ 60,394 Total ​ $ 62,818 ​ $ 1,842 ​ $ — ​ $ 64,660 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest rate swap agreement (3) ​ $ — ​ $ 9,055 ​ $ — ​ $ 9,055 Contingent consideration (4) ​ ​ — ​ ​ — ​ ​ 6,911 ​ ​ 6,911 Total ​ $ — ​ $ 9,055 ​ $ 6,911 ​ $ 15,966 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ ​ Quoted Prices in ​ Other Observable ​ Unobservable ​ ​ ​ ​ ​ Active Markets ​ Inputs ​ Inputs ​ ​ ​ $s in thousands (Level 1) (Level 2) (Level 3) Total Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed-income securities (1) ​ $ 2,380 ​ $ 1,830 ​ $ — ​ $ 4,210 Money market funds (2) ​ ​ 859 ​ ​ — ​ ​ — ​ ​ 859 Total ​ $ 3,239 ​ $ 1,830 ​ $ — ​ $ 5,069 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest rate swap agreement (3) ​ $ — ​ $ 1,176 ​ $ — ​ $ 1,176 Contingent consideration (4) ​ ​ — ​ ​ — ​ ​ 8,283 ​ ​ 8,283 Total ​ $ — ​ $ 1,176 ​ $ 8,283 ​ $ 9,459 (1) We invest a portion of our Restricted cash and investments in fixed-income securities, including U.S. Treasury and U.S. agency securities. We measure the fair value of U.S. Treasury securities using quoted prices for identical assets in active markets. We measure the fair value of U.S. agency securities using observable market activity for similar assets. The fair value of our fixed-income securities approximates our cost basis in the investments. ​ (2) We invest portions of our Cash and cash equivalents and Restricted cash and investments in money market funds. We measure the fair value of these money market fund investments using quoted prices for identical assets in active markets. The portion of Restricted cash and investments that is invested in money market funds is considered restricted cash for purposes of reconciling the beginning-of-period and end-of-period amounts presented in the Company’s consolidated statements of cash flows. ​ (3) In order to manage interest rate exposure, we entered into an interest rate swap agreement in March 2020 that effectively converts a portion of our variable-rate debt to a fixed interest rate. The swap is designated as a highly-effective cash flow hedge, with gains and losses deferred in other comprehensive income to be recognized as an adjustment to interest expense in the same period that the hedged interest payments affect earnings. The interest rate swap has an effective date of March 31, 2020 in an initial notional amount of $500.0 million. The fair value of the interest rate swap agreement represents the difference in the present value of cash flows calculated (i) at the contracted interest rates and (ii) at current market interest rates at the end of the period. We calculate the fair value of interest rate swap agreements quarterly based on the quoted market price for the same or similar financial instruments. The fair value of the interest rate swap agreement is included in Other long-term liabilities in the Company’s consolidated balance sheet. ​ (4) Our contingent consideration liabilities represent the estimated fair value of potential future payments the Company may be required to remit under the terms of historical purchase agreements entered into by NRC prior to the NRC Merger. The payments are contingent on the acquired businesses’ achievement of annual earnings targets in certain years and other events considered in the purchase agreements. The fair value of our contingent consideration liabilities are calculated using either a Monte Carlo simulation or modified Black-Scholes analyses based on earnings projections for the respective earn-out periods, corresponding earnings thresholds, and approximate timing of payments as outlined in the purchase agreements. The analyses utilize the following assumptions: (i) expected term; (ii) risk-adjusted net sales or earnings; (iii) risk-free interest rate; and (iv) expected volatility of earnings. Estimated payments, as determined through the respective models, are discounted by a credit spread assumption to account for credit risk. At March 31, 2020, the fair value of our contingent consideration liabilities of $5.5 million and $1.4 million were included in Accrued liabilities and Other long-term liabilities, respectively. At December 31, 2019, the fair value of our contingent consideration liabilities of $6.6 million and $1.7 million were included in Accrued liabilities and Other long-term liabilities, respectively. We revalue our contingent consideration payments each period and any increases or decreases to fair value are included in Selling, general and administrative expenses in our consolidated statements of operations. Fair values may be impacted by certain unobservable inputs, most significantly with regard to discount rates, expected volatility and historical and projected performance. Significant changes to these inputs in isolation could result in a significantly different fair value measurement. ​ ​ ​ ​ ​ ​ ​ Three Months Ended $s in thousands March 31, 2020 Contingent consideration, beginning of period ​ $ 8,283 Change in fair value of contingent consideration ​ ​ (1,127) Foreign currency translation ​ ​ (245) Contingent consideration, end of period ​ $ 6,911 ​

PROPERTY AND EQUIPMENT

PROPERTY AND EQUIPMENT	3 Months Ended
	Mar. 31, 2020
PROPERTY AND EQUIPMENT
PROPERTY AND EQUIPMENT	NOTE 8. PROPERTY AND EQUIPMENT ​ Property and equipment consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, ​ December 31, $s in thousands ​ 2020 2019 Cell development costs ​ $ 173,787 ​ $ 174,561 Land and improvements ​ 53,004 ​ 52,909 Buildings and improvements ​ 111,539 ​ 109,580 Railcars ​ 17,299 ​ 17,299 Vehicles, vessels and other equipment ​ 324,177 ​ 317,472 Construction in progress ​ 71,740 ​ 61,537 Total property and equipment ​ 751,546 ​ 733,358 Accumulated depreciation and amortization ​ (266,221) ​ (254,590) Property and equipment, net ​ $ 485,325 ​ $ 478,768 ​ Depreciation and amortization expense for the three months ended March 31, 2020 and 2019 was $18.0 million and $8.1 million, respectively.

LEASES

LEASES	3 Months Ended
	Mar. 31, 2020
LEASES
LEASES	NOTE 9. LEASES ​ We lease certain facilities, office space, land and equipment. Our lease payments are primarily fixed, but also include variable payments that are based on usage of the leased asset. Initial lease terms range from one may one None ​ Leases with an initial term of 12 months or less are not recorded on the balance sheet and expense is recognized on a straight-line basis over the lease term. We combine lease and non-lease components in our leases. We use the rate implicit in the lease, when available, to discount lease payments to present value. However, many of our leases do not provide a readily determinable implicit rate and we estimate our incremental borrowing rate to discount payments based on information available at lease commencement. ​ Lease assets and liabilities consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ $s in thousands March 31, 2020 December 31, 2019 Assets: ​ ​ ​ ​ ​ ​ Operating right-of-use assets (1) ​ $ 55,843 ​ $ 57,396 Finance right-of-use assets (2) ​ ​ 22,903 ​ ​ 20,499 Total ​ $ 78,746 ​ $ 77,895 ​ ​ ​ ​ ​ ​ ​ Liabilities: ​ ​ ​ ​ ​ ​ Current: ​ ​ ​ ​ ​ ​ Operating (3) ​ $ 17,813 ​ $ 17,317 Finance (4) ​ ​ 4,397 ​ ​ 4,128 Long-term: ​ ​ ​ ​ ​ ​ Operating (5) ​ ​ 38,092 ​ ​ 39,954 Finance (6) ​ ​ 19,098 ​ ​ 16,308 Total ​ $ 79,400 ​ $ 77,707 (1) Included in Operating lease assets in the Company’s consolidated balance sheets. (2) Included in Property and equipment, net in the Company’s consolidated balance sheets. Finance right-of-use assets are recorded net of accumulated amortization of $4.0 million and $2.7 million as of March 31, 2020 and December 31, 2019, respectively. (3) Included in Current portion of operating lease liabilities in the Company’s consolidated balance sheets. (4) Included in Accrued liabilities in the Company’s consolidated balance sheets. (5) Included in Long-term operating lease liabilities in the Company’s consolidated balance sheets. (6) Included in Other long-term liabilities in the Company’s consolidated balance sheets. ​ Lease expense consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, $s in thousands 2020 2019 Operating lease cost (1) ​ $ 4,999 ​ $ 1,742 Finance lease cost: ​ ​ ​ ​ ​ ​ Amortization of leased assets (2) ​ ​ 1,294 ​ ​ 228 Interest on lease liabilities (3) ​ ​ 318 ​ ​ 20 Total ​ $ 6,611 ​ $ 1,990 (1) Included in Direct operating costs and Selling, general, and administrative expenses in the Company’s consolidated statements of operations. Operating lease cost includes short-term leases, excluding expenses relating to leases with a term of one month or less, which are not material. Operating lease cost excludes variable lease costs which are not material. (2) Included in Direct operating costs in the Company’s consolidated statements of operations. (3) Included in Interest expense in the Company’s consolidated statements of operations. ​ Supplemental cash flow information related to our leases is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, $s in thousands 2020 2019 Cash paid for amounts included in the measurement of lease liabilities: ​ ​ ​ ​ ​ ​ Operating cash flows from operating leases ​ $ 4,851 ​ $ 1,615 Operating cash flows from finance leases ​ $ 318 ​ $ 20 Financing cash flows from finance leases ​ $ 1,128 ​ $ 199 ​ ​ ​ ​ ​ ​ ​ Non-cash investing and financing activities: ​ ​ ​ ​ ​ ​ Right-of-use assets obtained in exchange for new operating lease liabilities ​ $ 2,931 ​ $ 1,628 Right-of-use assets obtained in exchange for new finance lease liabilities ​ $ 4,192 ​ $ 1,844 ​

GOODWILL AND INTANGIBLE ASSETS

GOODWILL AND INTANGIBLE ASSETS	3 Months Ended
	Mar. 31, 2020
GOODWILL AND INTANGIBLE ASSETS
GOODWILL AND INTANGIBLE ASSETS	NOTE 10. GOODWILL AND INTANGIBLE ASSETS ​ Changes in goodwill for the three months ended March 31, 2020 consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Field & ​ ​ ​ ​ ​ Environmental ​ Industrial ​ ​ ​ ​ Services ​ Services ​ ​ ​ ​ ​ ​ ​ Accumulated ​ ​ ​ Accumulated ​ ​ ​ $s in thousands Gross Impairment Gross Impairment Total Balance at December 31, 2019 ​ $ 475,271 ​ $ (6,870) ​ $ 298,579 ​ $ — ​ $ 766,980 Impairment charges ​ ​ — ​ ​ (283,600) ​ ​ — ​ ​ (16,700) ​ ​ (300,300) NRC Merger purchase price allocation adjustment ​ ​ 575 ​ ​ — ​ ​ 446 ​ ​ — ​ ​ 1,021 Impact Environmental acquisition ​ ​ — ​ ​ — ​ ​ 300 ​ ​ — ​ ​ 300 Foreign currency translation ​ (1,368) ​ ​ — ​ (602) ​ ​ — ​ (1,970) Balance at March 31, 2020 ​ $ 474,478 ​ $ (290,470) ​ $ 298,723 ​ $ (16,700) ​ $ 466,031 ​ We assess goodwill for impairment during the fourth quarter as of October 1 of each year, and also if an event occurs or circumstances change that would more likely than not reduce the fair value of a reporting unit below its carrying amount. ​ In connection with our financial review and forecasting procedures performed during the first quarter of 2020, management determined that the projected future cash flows of our Energy Waste Disposal Services (“EWDS”) reporting unit and our International reporting unit (described below) indicated that the fair value of such reporting units may be below their respective carrying amounts. Accordingly, we performed an interim assessment of each reporting unit’s fair value as of March 31, 2020 (the “Interim Assessment”). Based on the results of the Interim Assessment, we recognized goodwill impairment charges of $283.6 million related to our EWDS reporting unit and $16.7 million related to our International reporting unit in the first quarter of 2020. As of March 31, 2020, after the recording these impairment charges, remaining goodwill balances for the EWDS and International reporting units were $25.8 million and $1.6 million, respectively. ​ Our EWDS reporting unit, a component of our Environmental Services segment, provides energy-related services including solid and liquid waste treatment and disposal, equipment cleaning and maintenance, specialty equipment rental, spill containment and site remediation for a full complement of oil and gas waste streams, predominately to upstream energy customers currently concentrated in the Eagle Ford and Permian Basins in Texas. Our International reporting unit, a component of our Field & Industrial Services segment, provides industrial and emergency response services to the offshore oil and gas sector in the North Sea and land-based industries across the EMEA region. Both our EWDS and International reporting units are dependent on energy-related exploration and production investments and expenditures by our energy industry customers. Lower crude oil prices and the volatility of such prices affect the level of investment as it impacts the ability of energy companies to access capital on economically advantageous terms or at all. In addition, energy companies decrease investments when the projected profits are inadequate or uncertain due to lower crude oil prices or volatility in crude oil prices. Such reductions in capital spending negatively impact energy waste generation and therefore the demand for our services. Recent volatility and historically low oil prices have adversely impacted customers of our EWDS reporting unit and our International reporting unit, negatively affecting demand for our services. ​ The principal factors contributing to the goodwill impairment charges for both the EWDS and International reporting units related to historically-low energy commodity prices reducing anticipated energy-related exploration and production investments and expenditures by our energy industry customers, which negatively impacted each reporting unit’s prospective cash flows and each reporting unit's estimated fair value. A longer-than-expected recovery in crude oil pricing and energy-related exploration and production investments became evident during the first quarter of 2020 as we assessed the projected impact of the COVID-19 pandemic and foreign oil production increases on the global demand for oil and updated the long-term projections for each reporting unit which, as a result, decreased each reporting unit’s anticipated future cash flows as compared to those estimated previously. The EWDS and International reporting units were acquired as part of the NRC Merger on November 1, 2019. As part of the preliminary purchase price allocation, the assets and liabilities of NRC were recorded at their preliminary fair value with the purchase price in excess of net fair value recorded as goodwill. Goodwill was allocated to the reporting units based on the relative preliminary fair value of each reporting unit to the total fair value of NRC. Consistent with our annual impairment testing methodology, we utilized a weighted average of (1) an income approach and (2) a market approach to determine the fair value of each of the reporting units for the Interim Assessment. The income approach is based on the estimated present value of future cash flows for each reporting unit. The market approach is based on assumptions about how market data relates to each reporting unit. Assessing impairment inherently involves management judgments as to the assumptions used to calculate fair value of the reporting units and the impact of market conditions on those assumptions. The key inputs that management uses in its assumptions to estimate the fair value of our reporting units under the income-based approach are as follows: ● Projected cash flows of the reporting unit, with consideration given to projected revenues, operating margins and the levels of capital investment required to generate the corresponding revenues; and ● Weighted average cost of capital (“WACC”), the risk-adjusted rate used to discount the projected cash flows. To develop the projected cash flows of our reporting units, management considers factors that may impact the revenue streams within each reporting unit. These factors include, but are not limited to, economic conditions on both a global scale and specifically in the regions in which the reporting units operate, customer relationships, strategic plans and opportunities, required returns on invested capital and competition from other service providers. With regard to operating margins, management considers its historical reporting unit operating margins on the revenue streams within each reporting unit, adjusting historical margins for the projected impact of current market trends on both fixed and variable costs. Expected future after-tax operating cash flows of each reporting unit are discounted to a present value using a risk-adjusted discount rate. Estimates of future cash flows require management to make significant assumptions regarding future operating performance including the projected mix of revenue streams within each reporting unit, projected operating margins, the amount and timing of capital investments and the overall probability of achieving the projected cash flows, as well as future economic conditions, which may result in actual future cash flows that are different than management’s estimates. The discount rate, which is intended to reflect the risks inherent in future cash flow projections, used in estimating the present value of future cash flows, is based on estimates of the WACC of market participants relative to the reporting units. Financial and credit market volatility can directly impact certain inputs and assumptions used to develop the WACC. The rapid and sustained decline in the energy markets served by our EWDS and International reporting units, exacerbated by the uncertainty surrounding the impact of the COVID-19 pandemic and foreign oil production increases, has inherently increased the risk associated with the future cash flows of these reporting units. Accordingly, when performing the Interim Assessment, we increased the discount rates and decreased the projected capital investment for each reporting unit compared to the assumptions used in the initial fair value assessment in connection with the NRC Merger on November 1, 2019. We believe these changes are reflective of market participant inputs in consideration of the current economic uncertainty. We also considered the estimated fair value of our EWDS and International reporting units under a market-based approach by applying industry-comparable multiples of revenues and operating earnings to reporting unit revenues and operating earnings. The lack of a broad base of publicly available market data specific to the industry in which we operate, combined with the general market volatility attributable to the COVID-19 pandemic, results in a wide range of currently observable market multiples. Accordingly, we applied less weight to the estimated fair value of our reporting units calculated under the market-based approach (10%) compared to the income approach (90%) described above. We believe that the discount rates, projected cash flows and other inputs and assumptions used in the Interim Assessment are consistent with those that a market participant would use based on the events described above and are reflective of the current market assessment of the fair value of our EWDS and International reporting units. In addition, we believe that our estimates and assumptions about future revenues and margin projections in the Interim Assessment were reasonable and consistent with the current economic uncertainty, both in general and specific to the energy markets served by our EWDS and International reporting units. As of March 31, 2020, the carrying values of our EWDS and International reporting units approximates their fair values. As such, there is a risk of additional goodwill impairment to either or both reporting units if future events related to the respective reporting unit are less favorable than what we have assumed or estimated in our Interim Assessment. We will continue to monitor events occurring or circumstances changing which may suggest that goodwill should be reevaluated during future interim periods prior to the annual impairment test. These events and circumstances include, but are not limited to, a further sustained decline in energy commodity prices and unanticipated impacts from the COVID-19 pandemic, as well as quantitative and qualitative factors specific to each reporting unit which indicate potential events that would more likely than not reduce the fair value of the reporting unit below its carrying amount. Additionally, the carrying values of our EWDS and International reporting units are based on preliminary estimates of their acquisition date fair values. As such, changes to these preliminary fair value estimates may result in an adjustment, during the measurement period, to the impairment charges recognized in the first quarter of 2020. See Note 3 for additional information on the preliminary nature of the NRC Merger purchase price allocation. Intangible assets, net consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, 2020 ​ December 31, 2019 ​ ​ ​ ​ ​ Accumulated ​ ​ ​ ​ ​ ​ ​ Accumulated ​ ​ ​ $s in thousands Cost Amortization Net Cost Amortization Net Amortizing intangible assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Permits, licenses and lease ​ $ 172,668 ​ $ (19,239) ​ $ 153,429 ​ $ 174,339 ​ $ (18,707) ​ $ 155,632 Customer relationships ​ ​ 333,152 ​ ​ (41,781) ​ ​ 291,371 ​ ​ 333,090 ​ ​ (35,254) ​ ​ 297,836 Technology - formulae and processes ​ 6,421 ​ (1,907) ​ 4,514 ​ 6,964 ​ (2,013) ​ 4,951 Customer backlog ​ 3,652 ​ (2,113) ​ 1,539 ​ 3,652 ​ (2,022) ​ 1,630 Tradename ​ 10,390 ​ ​ (5,644) ​ ​ 4,746 ​ ​ 10,390 ​ ​ (4,832) ​ ​ 5,558 Developed software ​ ​ 2,874 ​ ​ (1,936) ​ ​ 938 ​ ​ 2,895 ​ ​ (1,884) ​ ​ 1,011 Non-compete agreements ​ 5,506 ​ (2,372) ​ 3,134 ​ 5,455 ​ (1,694) ​ 3,761 Internet domain and website ​ ​ 536 ​ ​ (163) ​ ​ 373 ​ ​ 536 ​ ​ (156) ​ ​ 380 Database ​ ​ 382 ​ ​ (191) ​ ​ 191 ​ ​ 388 ​ ​ (191) ​ ​ 197 Total amortizing intangible assets ​ 535,581 ​ (75,346) ​ 460,235 ​ 537,709 ​ (66,753) ​ 470,956 Non-amortizing intangible assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Permits and licenses ​ 103,769 ​ ​ — ​ 103,769 ​ 103,816 ​ ​ — ​ 103,816 Tradename ​ 120 ​ ​ — ​ ​ 120 ​ 130 ​ ​ — ​ ​ 130 Total intangible assets ​ $ 639,470 ​ $ (75,346) ​ $ 564,124 ​ $ 641,655 ​ $ (66,753) ​ $ 574,902 ​ In connection with the interim goodwill impairment assessment of the EWDS and International reporting units, we also assessed the reporting units’ finite-lived tangible and intangible assets for impairment as of March 31, 2020. Based on the results of the assessment, the carrying amounts of the finite-lived tangible and intangible assets did not exceed the estimated undiscounted cash flows of the asset groups and, as a result, no impairment charges were recorded in the first quarter of 2020. ​ During the three months ended March 31, 2020, the Company acquired Impact Environmental Services, Inc. and recorded $300,000 of goodwill and $900,000 of amortizing intangible assets (consisting primarily of customer relationships). See Note 3 for additional information. ​ Amortization expense for the three months ended March 31, 2020 and 2019 was $9.4 million and $2.8 million, respectively. Foreign intangible asset carrying amounts are affected by foreign currency translation.

DEBT

DEBT	3 Months Ended
	Mar. 31, 2020
DEBT
DEBT	NOTE 11. DEBT ​ Long-term debt consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, ​ December 31, $s in thousands 2020 2019 Revolving credit facility ​ $ 417,396 ​ $ 327,000 Term loan ​ ​ 448,875 ​ ​ 450,000 Unamortized term loan discount and debt issuance costs ​ ​ (7,514) ​ ​ (7,799) Total debt ​ ​ 858,757 ​ ​ 769,201 Current portion of long-term debt and Short-term borrowings ​ ​ (3,754) ​ ​ (3,359) Long-term debt ​ $ 855,003 ​ $ 765,842 ​ Credit Agreement ​ On April 18, 2017, US Ecology Holdings, Inc. (f/k/a US Ecology, Inc.) (“Predecessor US Ecology”), now a wholly-owned subsidiary of the Company, entered into a new senior secured credit agreement (the “Credit Agreement”) with Wells Fargo Bank, National Association (“Wells Fargo”), as administrative agent for the lenders, swingline lender and issuing lender, and Bank of America, N.A., as an issuing lender, that provides for a $500.0 million, five-year revolving credit facility (the “Revolving Credit Facility”), including a $75.0 million sublimit for the issuance of standby letters of credit and a $40.0 million sublimit for the issuance of swingline loans used to fund short-term working capital requirements. The Credit Agreement also contains an accordion feature whereby Predecessor US Ecology may request up to $200.0 million of additional funds through an increase to the Revolving Credit Facility, through incremental term loans, or some combination thereof. As described below, the Credit Agreement was amended in November 2019 in connection with the NRC Merger. ​ The Revolving Credit Facility provides up to $500.0 million of revolving credit loans or letters of credit with the use of proceeds restricted solely for working capital and other general corporate purposes (including acquisitions and capital expenditures). Under the Revolving Credit Facility, revolving credit loans are available based on a base rate (as defined in the Credit Agreement) or the London Inter-Bank Offered Rate (“LIBOR”), at the Company’s option, plus an applicable margin which is determined according to a pricing grid under which the interest rate decreases or increases based on our ratio of funded debt to consolidated earnings before interest, taxes, depreciation and amortization (as defined in the Credit Agreement), as set forth in the table below: ​ ​ ​ ​ Total Net Leverage Ratio LIBOR Rate Loans Interest Margin Base Rate Loans Interest Margin Equal to or greater than 3.25 to 1.00 2.00% 1.00% Equal to or greater than 2.50 to 1.00, but less than 3.25 to 1.00 1.75% 0.75% Equal to or greater than 1.75 to 1.00, but less than 2.50 to 1.00 1.50% 0.50% Equal to or greater than 1.00 to 1.00, but less than 1.75 to 1.00 1.25% 0.25% Less than 1.00 to 1.00 1.00% 0.00% ​ During the three months ended March 31, 2020, the effective interest rate on the Revolving Credit Facility, after giving effect to the impact of our interest rate swap and the amortization of the loan discount and debt issuance costs, was 3.96%. Interest only payments are due either quarterly or on the last day of any interest period, as applicable. ​ Predecessor US Ecology is required to pay a commitment fee ranging from 0.175% to 0.35% on the average daily unused portion of the Revolving Credit Facility, with such commitment fee to be reduced based upon Predecessor US Ecology’s total net leverage ratio (as defined in the Credit Agreement). The maximum letter of credit capacity under the Revolving Credit Facility is $75.0 million and the Credit Agreement provides for a letter of credit fee equal to the applicable margin for LIBOR loans under the Revolving Credit Facility. At March 31, 2020, there were $417.4 million of revolving credit loans outstanding on the Revolving Credit Facility. These revolving credit loans are due upon the earliest to occur of (i) November 1, 2024 (or, with respect to any lender, such later date as requested by us and accepted by such lender), (ii) the date of termination of the entire revolving credit commitment (as defined in the Credit Agreement) by us, and (iii) the date of termination of the revolving credit commitment and are presented as long-term debt in the consolidated balance sheets. ​ Predecessor US Ecology has entered into a sweep arrangement whereby day-to-day cash requirements in excess of available cash balances are advanced to the Company on an as-needed basis with repayments of these advances automatically made from subsequent deposits to our cash operating accounts (the “Sweep Arrangement”). Total advances outstanding under the Sweep Arrangement are subject to the $40.0 million swingline loan sublimit under the Revolving Credit Facility. Predecessor US Ecology’s revolving credit loans outstanding under the Revolving Credit Facility are not subject to repayment through the Sweep Arrangement. As of March 31, 2020, there were $396,000 in borrowings outstanding subject to the Sweep Arrangement. ​ As of March 31, 2020, the availability under the Revolving Credit Facility was $75.9 million with $6.7 million of the Revolving Credit Facility issued in the form of standby letters of credit utilized as collateral for closure and post-closure financial assurance and other assurance obligations. ​ Predecessor US Ecology may at any time and from time to time prepay revolving credit loans and swingline loans, in whole or in part, without premium or penalty, subject to the obligation to indemnify each of the lenders against any actual loss or expense (including any loss or expense arising from the liquidation or reemployment of funds obtained by it to maintain a LIBOR rate loan (as defined in the Credit Agreement) or from fees payable to terminate the deposits from which such funds were obtained) with respect to the early termination of any LIBOR rate loan. The Credit Agreement provides for mandatory prepayment at any time if the revolving credit outstanding exceeds the revolving credit commitment (as such terms are defined in the Credit Agreement), in an amount equal to such excess. Subject to certain exceptions, the Credit Agreement provides for mandatory prepayment upon certain asset dispositions, casualty events and issuances of indebtedness. ​ Pursuant to (i) an unconditional guarantee agreement and (ii) a collateral agreement, each entered into by Predecessor US Ecology and its domestic subsidiaries on April 18, 2017, Predecessor US Ecology’s obligations under the Credit Agreement are (or will be) jointly and severally and fully and unconditionally guaranteed on a senior basis by all of the Company’s existing and certain future domestic subsidiaries and are secured by substantially all of the assets of Predecessor US Ecology and the Company’s existing and certain future domestic subsidiaries (subject to certain exclusions), including 100% of the equity interests of the Company’s domestic subsidiaries and 65% of the voting equity interests of the Company’s directly owned foreign subsidiaries (and 100% of the non-voting equity interests of the Company’s directly owned foreign subsidiaries). ​ The Credit Agreement contains customary restrictive covenants, subject to certain permitted amounts and exceptions, including covenants limiting the ability of the Company to incur additional indebtedness, pay dividends and make other restricted payments, repurchase shares of our outstanding stock and create certain liens. Upon the occurrence of an event of default (as defined in the Credit Agreement), among other things, amounts outstanding under the Credit Agreement may be accelerated and the commitments may be terminated. ​ The Credit Agreement also contains financial maintenance covenants, a maximum consolidated total net leverage ratio and a consolidated interest coverage ratio (as such terms are defined in the Credit Agreement). Our consolidated total net leverage ratio as of the last day of any fiscal quarter, commencing with the fiscal quarter ending June 30, 2017, may not exceed 4.00 to 1.00, subject to certain exceptions. Our consolidated interest coverage ratio as of the last day of any fiscal quarter, commencing with the fiscal quarter ending June 30, 2017, may not be less than 3.00 to 1.00. ​ Amendments to the Credit Agreement ​ On August 6, 2019, Predecessor US Ecology entered into the first amendment (the “First Amendment”) to the Credit Agreement, by and among Predecessor US Ecology, the subsidiaries of Predecessor US Ecology party thereto, the lenders referred to therein and Wells Fargo, as issuing lender, swingline lender and administrative agent. Effective November 1, 2019, the First Amendment, among other things, extended the expiration of the Revolving Credit Facility to November 1, 2024, permitted the issuance of a $400.0 million incremental term loan to be used to refinance the indebtedness of NRC and pay related transaction expenses in connection with the NRC Merger, modified the accordion feature allowing Predecessor US Ecology to request up to the greater of (x) $250.0 million and (y) 100% of consolidated EBITDA plus certain additional amounts, increased the sublimit for the issuance of swingline loans to $40.0 million and increased the maximum consolidated total net leverage ratio to 4.00 to 1.00. ​ On November 1, 2019, Predecessor US Ecology entered into the lender joinder agreement and second amendment (the “Second Amendment”) to the Credit Agreement. Effective November 1, 2019, the Second Amendment, among other things, amended the Credit Agreement to increase the capacity for incremental term loans by $50.0 million and provided for Wells Fargo lending $450.0 million in incremental term loans to Predecessor US Ecology to pay off the existing debt of NRC in connection with the NRC Merger, to pay certain fees, costs and expenses incurred in connection with the NRC Merger and to repay outstanding borrowings under the Revolving Credit Facility. The seven-year incremental term loan matures November 1, 2026, requires principal repayment of 1% annually, and bears interest at LIBOR plus 2.25% or a base rate plus 1.25% (with a step-up to LIBOR plus 2.50% or a base rate plus 1.50% in the event that US Ecology credit ratings are not BB (with a stable or better outlook) or better from S&P and Ba2 (with a stable or better outlook) or better from Moody’s). During the three months ended March 31, 2020, the effective interest rate on the term loan, including the impact of the amortization of debt issuance costs, was 4.39%. ​ At March 31, 2020, we were in compliance with all of the financial covenants in the Credit Agreement. ​ Interest Rate Swap ​ In March 2020, the Company entered into an interest rate swap agreement with Wells Fargo, effectively fixing the interest rate on $500.0 million, or approximately 58%, of the Revolving Credit Facility and term loan borrowings outstanding as of March 31, 2020. In connection with our entry into the March 2020 interest rate swap, we terminated our existing interest rate swap prior to its scheduled maturity date of June 2021. As the original hedged forecasted transaction (periodic interest payments on our variable-rate debt) remains probable, the $1.8 million net loss related to the terminated swap reported in AOCI at the termination date will be amortized as additional interest expense over its original maturity.

CLOSURE AND POST-CLOSURE OBLIGA

CLOSURE AND POST-CLOSURE OBLIGATIONS	3 Months Ended
	Mar. 31, 2020
CLOSURE AND POST-CLOSURE OBLIGATIONS
CLOSURE AND POST-CLOSURE OBLIGATIONS	NOTE 12. CLOSURE AND POST-CLOSURE OBLIGATIONS ​ Our accrued closure and post-closure liability represents the expected future costs, including corrective actions, associated with closure and post-closure of our operating and non-operating disposal facilities. We record the fair value of our closure and post-closure obligations as a liability in the period in which the regulatory obligation to retire a specific asset is triggered. For our individual landfill cells, the required closure and post-closure obligations under the terms of our permits and our intended operation of the landfill cell are triggered and recorded when the cell is placed into service and waste is initially disposed in the landfill cell. The fair value is based on the total estimated costs to close the landfill cell and perform post-closure activities once the landfill cell has reached capacity and is no longer accepting waste. We perform periodic reviews of both non-operating and operating facilities and revise accruals for estimated closure and post-closure, remediation or other costs as necessary. Recorded liabilities are based on our best estimates of current costs and are updated periodically to include the effects of existing technology, presently enacted laws and regulations, inflation and other economic factors. ​ Changes to closure and post-closure obligations consisted of the following: ​ ​ ​ ​ ​ ​ ​ Three Months Ended $s in thousands March 31, 2020 Closure and post-closure obligations, beginning of period ​ $ 86,383 Accretion expense ​ 1,266 Payments ​ (418) Foreign currency translation ​ (135) Closure and post-closure obligations, end of period ​ 87,096 Less current portion ​ (2,704) Long-term portion ​ $ 84,392 ​

INCOME TAXES

INCOME TAXES	3 Months Ended
	Mar. 31, 2020
INCOME TAXES
INCOME TAXES	NOTE 13. INCOME TAXES ​ Our effective tax rate for the three months ended March 31, 2020 was 0.1%, down from 27.4% for the three months ended March 31, 2019. This decrease was primarily due to non-deductible goodwill impairment charges as well as lower domestic earnings resulting in a year to date tax benefit offset by foreign earnings tax expense during the three months ended March 31, 2020 compared to the three months ended March 31, 2019. ​ Gross unrecognized tax benefits, included in Other long-term liabilities in the consolidated balance sheets, were $8.4 million and $8.3 million as of March 31, 2020 and December 31, 2019, respectively. The gross unrecognized tax benefits, if recognized by the Company, will result in a reduction of approximately $300,000 to the provision for income taxes thereby favorably impacting the Company’s effective tax rate. The remaining $8.1 million is related to the acquired NRC net operating losses and is recorded as a reduction to our net operating losses deferred tax asset. We do not anticipate that the amount of existing unrecognized tax benefits will significantly increase or decrease within the next 12 months. Accrued interest and penalties related to unrecognized tax benefits are recorded as interest expense and selling, general and administrative expenses, respectively. The total accrued interest related to unrecognized tax benefits as of March 31, 2020 and December 31, 2019 were not significant. There is no ​ The Company files income tax returns in the United States and various state, local and foreign jurisdictions. The Company is subject to examination by the IRS for tax years 2016 through 2019. The 2014 through 2019 state tax returns are subject to examination by state tax authorities. US Ecology Sarnia is currently under examination by the Canadian Revenue Agency for the pre-acquisition years 2016 and 2017. The tax years 2015 through 2019 remain subject to examination in our significant foreign jurisdictions. The Company does not anticipate any material change as a result of any current examinations in progress. ​

EARNINGS (LOSS) PER SHARE

EARNINGS (LOSS) PER SHARE	3 Months Ended
	Mar. 31, 2020
EARNINGS (LOSS) PER SHARE
EARNINGS (LOSS) PER SHARE	NOTE 14. EARNINGS (LOSS) PER SHARE ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, ​ ​ 2020 ​ 2019 $s and shares in thousands, except per share amounts Basic Diluted Basic Diluted Net (loss) income ​ $ (298,086) ​ $ (298,086) ​ $ 8,043 ​ $ 8,043 Weighted average basic shares outstanding ​ 31,305 ​ 31,305 ​ 21,987 ​ 21,987 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Dilutive effect of share-based awards and warrants ​ ​ ​ ​ — ​ ​ ​ ​ 210 Weighted average diluted shares outstanding ​ ​ ​ ​ 31,305 ​ ​ ​ ​ 22,197 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (Loss) earnings per share ​ $ (9.52) ​ $ (9.52) ​ $ 0.37 ​ $ 0.36 Anti-dilutive shares excluded from calculation ​ ​ ​ ​ 4,131 ​ ​ ​ ​ 79 ​

EQUITY

EQUITY	3 Months Ended
	Mar. 31, 2020
EQUITY
EQUITY	NOTE 15. EQUITY ​ Stock Repurchase Program ​ On June 1, 2016, the Company’s Board of Directors authorized the repurchase of up to $25.0 million of the Company’s outstanding common stock. On May 29, 2018, the repurchase program was extended and will remain in effect until June 6, 2020, unless further extended by our Board of Directors. On December 30, 2019, the Company’s Board of Directors authorized the repurchase of up to $25.0 million of the Company’s outstanding warrants (such dollar amount considered in the aggregate with the dollar amount of shares of common stock repurchased by the Company, if any, under the Company’s share repurchase program) as part of the Company’s share repurchase program. Repurchases may be made from time to time in the open market or through privately negotiated transactions. The timing of any repurchases of common stock or warrants will be based upon prevailing market conditions and other factors. The Company may from time to time also consider other options for repurchasing some or all of its warrants, including but not limited to a tender offer for all of the outstanding warrants. During the three months ended March 31, 2020, the Company repurchased 397,600 shares of common stock in an aggregate amount of $17.3 million under the repurchase program. ​ Omnibus Incentive Plan ​ On May 27, 2015, the stockholders of Predecessor US Ecology approved the Omnibus Incentive Plan (as amended, “Omnibus Plan”), which was approved by Predecessor US Ecology’s Board of Directors on April 7, 2015. In connection with the closing of the NRC Merger, the Company assumed the Omnibus Plan by adopting the Amended and Restated US Ecology, Inc. Omnibus Incentive Plan for the purposes of issuing replacement awards to award recipients under the Omnibus Plan pursuant to the Merger Agreement and for the issuance of additional awards in the future. The Omnibus Plan was developed to provide additional incentives through equity ownership in US Ecology and, as a result, encourage employees and directors to contribute to our success. The Omnibus Plan provides, among other things, the ability for the Company to grant restricted stock, performance stock, options, stock appreciation rights, restricted stock units, performance stock units and other share-based awards or cash awards to officers, employees, consultants and non-employee directors. The Omnibus Plan expires on April 7, 2025 and authorizes 1,500,000 shares of common stock for grant over the life of the Omnibus Plan. As of March 31, 2020, 540,801 shares of common stock remain available for grant under the Omnibus Plan. Subsequent to the approval of the Omnibus Plan by Predecessor US Ecology in May 2015, we stopped granting equity awards under our 2008 Stock Option Incentive Plan (“2008 Stock Option Plan”). However, in connection with the closing of the NRC Merger, the Company assumed the 2008 Stock Option Plan for the purpose of issuing replacement awards to award recipients thereunder and will remain in effect solely for the settlement of awards granted under such plan. No shares that are reserved but unissued under the 2008 Stock Option Plan or that are outstanding under the 2008 Stock Option Plan and reacquired by the Company for any reason will be available for issuance under the Omnibus Plan. In addition, in connection with the closing of the NRC Merger, the Company assumed the NRC Group Holdings Corp. 2018 Equity Incentive Plan previously maintained by NRC by adopting the Amended and Restated US Ecology, Inc. 2018 Equity and Incentive Compensation Plan. Like the 2008 Stock Option Plan, the NRC Group Holdings Corp. 2018 Equity Incentive Plan was assumed by the Company solely for the purpose of issuing replacement awards to award recipients pursuant to the Merger Agreement, and no future grants may be made under the 2018 Equity and Incentive Compensation Plan. ​ PSUs, RSUs and Restricted Stock ​ On January 24, 2020, the Company granted 5,358 PSUs to certain employees. Each PSU represents the right to receive, on the settlement date, one share of the Company’s common stock. The actual number of PSUs that will vest and be settled in shares is determined based on the achievement of certain milestones. The fair value of the PSUs estimated on the grant date was $54.55 per unit. Compensation expense is recorded over the awards’ milestone measurement period. ​ A summary of our PSU, restricted stock and RSU activity for the three months ended March 31, 2020 is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ PSUs ​ Restricted Stock ​ RSUs ​ ​ ​ ​ Weighted ​ ​ ​ Weighted ​ ​ ​ Weighted ​ ​ ​ ​ Average ​ ​ ​ Average ​ ​ ​ Average ​ ​ ​ ​ Grant Date ​ ​ ​ Grant Date ​ ​ ​ Grant Date ​ Shares Fair Value Shares Fair Value Shares Fair Value Outstanding as of December 31, 2019 42,711 ​ $ 61.11 64,654 ​ $ 55.62 ​ 131,199 ​ $ 59.05 Granted 5,358 ​ ​ 54.55 30,000 ​ ​ 57.04 ​ 108,540 ​ ​ 32.91 Vested (11,500) ​ 62.45 (34,688) ​ 52.43 ​ (41,364) ​ 55.26 Cancelled, expired or forfeited — ​ — — ​ — ​ (8,966) ​ 60.15 Outstanding as of March 31, 2020 36,569 ​ $ 59.73 59,966 ​ $ 58.18 ​ 189,409 ​ $ 44.85 ​ During the three months ended March 31, 2020, 11,500 PSUs vested and PSU holders earned 6,797 shares of the Company’s common stock. ​ Stock Options ​ A summary of our stock option activity for the three months ended March 31, 2020 is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ Average ​ ​ ​ ​ Exercise ​ Shares Price Outstanding as of December 31, 2019 293,588 ​ $ 48.23 Granted 67,900 ​ ​ 57.04 Exercised (4,880) ​ 43.13 Cancelled, expired or forfeited (5,415) ​ 42.43 Outstanding as of March 31, 2020 351,193 ​ $ 50.10 Exercisable as of March 31, 2020 240,763 ​ $ 46.52 ​ During the three months ended March 31, 2020, option holders tendered 3,738 options in connection with options exercised via net share settlement. ​ Treasury Stock ​ During the three months ended March 31, 2020, the Company repurchased 17,169 shares of the Company’s common stock in connection with the net share settlement of employee equity awards at an average cost of $57.91 per share and repurchased 397,600 shares of the Company’s common stock under our stock repurchase program at an average cost of $43.61 per share. ​ Dividends ​ The Company paid dividends of $0.18 per common share during each of the three months ended March 31, 2020 and 2019. On March 31, 2020, the Board of Directors approved a plan to suspend quarterly cash dividends, beginning with the second quarter of 2020.

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	3 Months Ended
	Mar. 31, 2020
COMMITMENTS AND CONTINGENCIES
COMMITMENTS AND CONTINGENCIES	NOTE 16. COMMITMENTS AND CONTINGENCIES ​ Litigation and Regulatory Proceedings ​ In the ordinary course of business, we are involved in judicial and administrative proceedings involving federal, state, provincial or local governmental authorities, including regulatory agencies that oversee and enforce compliance with permits. Fines or penalties may be assessed by our regulators for non-compliance. Actions may also be brought by individuals or groups in connection with permitting of planned facilities, modification or alleged violations of existing permits, or alleged damages suffered from exposure to hazardous substances purportedly released from our operated sites, as well as other litigation. We maintain insurance intended to cover property and damage claims asserted as a result of our operations. Periodically, management reviews and may establish reserves for legal and administrative matters, or other fees expected to be incurred in relation to these matters. In December 2010, National Response Corporation, a subsidiary of NRC acquired by the Company in the NRC Merger, was named as one of many “Dispersant Defendants” in multi-district litigation, arising out of the explosion of the BP Deepwater Horizon (“BP”) oil rig, filed in the U.S. District Court for the Eastern District of Louisiana (“ In re Deepwater Horizon In January 2019, Kevin Sullivan, a driver for NRC from May 1, 2018 to August 22, 2018 filed a class action complaint against NRC in California Superior Court ( Kevin Sullivan et. Al. v. National Response Corp., NRC Environmental Services, Inc. and Paul Taveira et al. On November 17, 2018, an explosion occurred at our Grand View, Idaho facility, resulting in one employee fatality and injuries to other employees. The incident severely damaged the facility’s primary waste-treatment building as well as surrounding waste handling, waste storage, maintenance and administrative support structures, resulting in the closure of the entire facility that remained in effect through January 2019. In addition to initiating and conducting our own investigation into the incident, we fully cooperated with the Idaho Department of Environmental Quality, the U.S. Environmental Protection Agency and the Occupational Safety and Health Administration (“OSHA”) to support their comprehensive and independent investigations of the incident. On January 10, 2020, we entered into a settlement agreement with OSHA settling a complaint made by OSHA relating to the incident for $50,000. On January 28, 2020, the Occupational Safety and Health Review Commission issued an order terminating the proceeding relating to such OSHA complaint. We have not otherwise been named as a defendant in any action relating to the incident. We maintain workers’ compensation insurance, business interruption insurance and liability insurance for personal injury, property and casualty damage. We believe that any potential third-party claims associated with the explosion in excess of our deductibles are expected to be resolved primarily through our insurance policies. Although we carry business interruption insurance, a disruption of our business caused by a casualty event, including the full and partial closure of our Grand View, Idaho facility, may result in the loss of business, profits or customers during the time of such closure. Accordingly, our insurance policies may not fully compensate us for these losses. ​ The Company is actively working with its insurance companies on comprehensive property and business interruption insurance claims related to the incident at our Grand View, Idaho facility in the fourth quarter of 2018. The Company recognized insurance recoveries of $462,000 for the three months ended March 31, 2020, related to expenses incurred to continue limited operations at the facility. ​ Other than as described above, during the period covered by this Quarterly Report on Form 10-Q, we have not been a party to any material legal proceedings.

OPERATING SEGMENTS

OPERATING SEGMENTS	3 Months Ended
	Mar. 31, 2020
OPERATING SEGMENTS
OPERATING SEGMENTS	NOTE 17. OPERATING SEGMENTS ​ Financial Information by Segment ​ Our operations are managed in two reportable segments reflecting our internal management reporting structure and nature of services offered as follows: ​ Environmental Services ​ Field & Industrial Services ​ The operations not managed through our two reportable segments are recorded as “Corporate.” Corporate selling, general and administrative expenses include typical corporate items such as legal, accounting and other items of a general corporate nature. Income taxes are assigned to Corporate, but all other items are included in the segment where they originated. Inter-company transactions have been eliminated from the segment information and are not significant between segments. ​ Summarized financial information of our reportable segments is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, 2020 ​ ​ ​ ​ Field & ​ ​ ​ ​ ​ ​ ​ ​ Environmental ​ Industrial ​ ​ ​ ​ ​ ​ $s in thousands Services Services Corporate Total Revenue ​ $ 126,745 ​ $ 113,975 ​ $ — ​ $ 240,720 Depreciation, amortization and accretion ​ $ 16,042 ​ $ 12,015 ​ $ 628 ​ $ 28,685 Capital expenditures ​ $ 11,532 ​ $ 5,289 ​ $ 2,310 ​ $ 19,131 Total assets ​ $ 997,271 ​ $ 878,774 ​ $ 102,594 ​ $ 1,978,639 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, 2019 ​ ​ ​ ​ Field & ​ ​ ​ ​ ​ ​ ​ ​ Environmental ​ Industrial ​ ​ ​ ​ ​ ​ $s in thousands Services Services Corporate Total Revenue ​ $ 92,332 ​ $ 38,705 ​ $ — ​ $ 131,037 Depreciation, amortization and accretion ​ $ 9,625 ​ $ 2,132 ​ $ 304 ​ $ 12,061 Capital expenditures ​ $ 6,712 ​ $ 178 ​ $ 333 ​ $ 7,223 Total assets ​ $ 703,453 ​ $ 161,299 ​ $ 68,580 ​ $ 933,332 ​ Adjusted Earnings Before Interest, Taxes, Depreciation and Amortization (“Adjusted EBITDA”) ​ Management uses Adjusted EBITDA as a financial measure to assess segment performance. Adjusted EBITDA is defined as net income before interest expense, interest income, income tax expense, depreciation, amortization, share-based compensation, accretion of closure and post-closure liabilities, foreign currency gain/loss, non-cash property and equipment impairment charges, non-cash goodwill impairment charges, gain on property insurance recoveries, business development and integration expenses and other income/expense. In 2019, we updated our Adjusted EBITDA definition to include adjustments for business development and integration expenses and gain on property insurance recoveries. Throughout this Quarterly Report on Form 10-Q, our Adjusted EBITDA results for all periods presented have been recast to reflect these adjustments. Adjusted EBITDA is a complement to results provided in accordance with GAAP and we believe that such information provides additional useful information to analysts, stockholders and other users to understand the Company’s operating performance. Since Adjusted EBITDA is not a measurement determined in accordance with GAAP and is thus susceptible to varying calculations, Adjusted EBITDA as presented may not be comparable to other similarly titled measures of other companies. Items excluded from Adjusted EBITDA are significant components in understanding and assessing our financial performance. Adjusted EBITDA should not be considered in isolation or as an alternative to, or substitute for, net income, cash flows generated by operations, investing or financing activities, or other financial statement data presented in the consolidated financial statements as indicators of financial performance or liquidity. Adjusted EBITDA has limitations as an analytical tool and should not be considered in isolation or a substitute for analyzing our results as reported under GAAP. Some of the limitations are: ● Adjusted EBITDA does not reflect changes in, or cash requirements for, our working capital needs; ● Adjusted EBITDA does not reflect our interest expense, or the requirements necessary to service interest or principal payments on our debt; ● Adjusted EBITDA does not reflect our income tax expenses or the cash requirements to pay our taxes; ● Adjusted EBITDA does not reflect our cash expenditures or future requirements for capital expenditures or contractual commitments; ● Although depreciation and amortization charges are non-cash charges, the assets being depreciated and amortized will often have to be replaced in the future, and Adjusted EBITDA does not reflect any cash requirements for such replacements; and ● Adjusted EBITDA does not reflect our business development and integration expenses. ​ A reconciliation of Net income to Adjusted EBITDA is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, $s in thousands 2020 2019 Net (loss) income ​ $ (298,086) ​ $ 8,043 Income tax (benefit) expense ​ ​ (263) ​ ​ 3,041 Interest expense ​ ​ 9,310 ​ ​ 4,030 Interest income ​ ​ (89) ​ ​ (207) Foreign currency (gain) loss ​ ​ (937) ​ ​ 139 Other income ​ ​ (171) ​ ​ (110) Property and equipment impairment charges ​ ​ — ​ ​ 25 Goodwill impairment charges ​ ​ 300,300 ​ ​ — Depreciation and amortization of plant and equipment ​ ​ 17,978 ​ ​ 8,125 Amortization of intangible assets ​ ​ 9,441 ​ ​ 2,811 Share-based compensation ​ ​ 1,564 ​ ​ 1,222 Accretion and non-cash adjustment of closure & post-closure liabilities ​ ​ 1,266 ​ ​ 1,125 Gain on property insurance recoveries ​ ​ — ​ ​ (4,653) Business development and integration expenses ​ ​ 2,907 ​ ​ 141 Adjusted EBITDA ​ $ 43,220 ​ $ 23,732 ​ Adjusted EBITDA, by operating segment, is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, $s in thousands ​ 2020 2019 Environmental Services $ 46,124 ​ $ 35,260 Field & Industrial Services 14,478 ​ 2,554 Corporate (17,382) ​ (14,082) Total $ 43,220 ​ $ 23,732 ​ Property and Equipment and Intangible Assets Outside of the United States ​ We provide services primarily in the United States, Canada and the EMEA region. Long-lived assets, comprised of property and equipment and intangible assets net of accumulated depreciation and amortization, by geographic location are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, ​ December 31, $s in thousands ​ 2020 2019 United States ​ $ 946,125 ​ $ 954,102 Canada ​ 64,383 ​ 70,691 EMEA ​ ​ 22,940 ​ ​ 23,587 Other (1) ​ ​ 16,001 ​ ​ 5,290 Total long-lived assets ​ $ 1,049,449 ​ $ 1,053,670 (1) Includes Mexico, Asia Pacific, and Latin America and Caribbean geographical regions.

GENERAL (Policies)

GENERAL (Policies)	3 Months Ended
	Mar. 31, 2020
GENERAL
Basis of Presentation	Basis of Presentation ​ The accompanying unaudited consolidated financial statements include the results of operations, financial position and cash flows of US Ecology, Inc. and its wholly-owned subsidiaries. All inter-company balances have been eliminated. Throughout these consolidated financial statements words such as “we,” “us,” “our,” “US Ecology” and “the Company” refer to US Ecology, Inc. and its subsidiaries. ​ In the opinion of management, the accompanying unaudited consolidated financial statements include all adjustments (consisting only of normal recurring adjustments) necessary to present fairly, in all material respects, the results of the Company for the periods presented. These consolidated financial statements have been prepared by the Company pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”). Certain information and footnote disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States (“GAAP”) have been omitted pursuant to the rules and regulations of the SEC. These consolidated financial statements should be read in conjunction with the consolidated financial statements and accompanying notes included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2019. The results of operations for the three months ended March 31, 2020 are not necessarily indicative of the results to be expected for the entire year ending December 31, 2020. ​ The Company’s consolidated balance sheet as of December 31, 2019 has been derived from the Company’s audited consolidated balance sheet as of that date.
Use of Estimates	Use of Estimates ​ The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the financial statements, as well as the reported amounts of revenue and expenses during the reporting period. Actual results could differ materially from the estimates and assumptions that we use in the preparation of our consolidated financial statements. As it relates to estimates and assumptions in amortization rates and environmental obligations, significant engineering, operations and accounting judgments are required. We review these estimates and assumptions no less than annually. In many circumstances, the ultimate outcome of these estimates and assumptions will not be known for decades into the future. Actual results could differ materially from these estimates and assumptions due to changes in applicable regulations, changes in future operational plans and inherent imprecision associated with estimating environmental impacts far into the future.
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements ​ In December 2019, the FASB issued ASU No. 2019-12, “Income Taxes” (Topic 740): Simplifying the Accounting for Income Taxes (“ASU 2019-12”), which is intended to simplify various aspects related to accounting for income taxes. ASU 2019-12 removes certain exceptions to the general principles in Topic 740 and also clarifies and amends existing guidance to improve consistent application. This guidance is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2020, with early adoption permitted. The Company is currently evaluating the impact of this standard on its consolidated financial statements and related disclosures. In June 2016, the FASB issued ASU No. 2016-13, “Financial Instruments - Credit Losses” (Topic 326), which became effective for reporting periods beginning after December 15, 2019. The standard replaced the incurred loss impairment methodology under current GAAP with a methodology that reflects expected credit losses and requires the use of a forward-looking expected credit loss model for accounts receivables, loans, and other financial instruments. The standard requires a modified retrospective approach through a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period in which the guidance is effective. The Company adopted the new credit loss standard effective January 1, 2020 and the impact of the adoption was not material to the Company's consolidated financial statements as credit losses are not expected to be significant based on historical collection trends, the financial condition of payment partners, and external market factors. The Company will continue to actively monitor the impact of the recent coronavirus (‘COVID-19”) pandemic on expected credit losses.

REVENUES (Tables)

REVENUES (Tables)	3 Months Ended
	Mar. 31, 2020
REVENUES
Schedule of disaggregation of revenues	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, 2020 ​ ​ ​ ​ Field & ​ ​ ​ ​ ​ Environmental ​ Industrial ​ ​ ​ $s in thousands Services Services Total Treatment & Disposal Revenue (1) ​ $ 100,049 ​ $ 9,984 ​ $ 110,033 Services Revenue: ​ ​ ​ ​ ​ ​ ​ ​ ​ Transportation and Logistics (2) ​ ​ 26,696 ​ ​ 6,154 ​ ​ 32,850 Industrial Services (3) ​ ​ — ​ ​ 28,478 ​ ​ 28,478 Small Quantity Generation (4) ​ ​ — ​ ​ 11,084 ​ ​ 11,084 Total Waste Management (5) ​ ​ — ​ ​ 8,482 ​ ​ 8,482 Remediation (6) ​ ​ — ​ ​ 10,441 ​ ​ 10,441 Emergency Response (7) ​ ​ — ​ ​ 24,922 ​ ​ 24,922 Domestic Standby Services (8) ​ ​ — ​ ​ 9,467 ​ ​ 9,467 Other (9) ​ ​ — ​ ​ 4,963 ​ ​ 4,963 Revenue ​ $ 126,745 ​ $ 113,975 ​ $ 240,720 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, 2019 ​ ​ ​ ​ Field & ​ ​ ​ ​ ​ Environmental ​ Industrial ​ ​ ​ $s in thousands Services Services Total Treatment & Disposal Revenue (1) ​ $ 77,713 ​ $ 2,796 ​ $ 80,509 Services Revenue: ​ ​ ​ ​ ​ ​ ​ ​ ​ Transportation and Logistics (2) ​ ​ 14,619 ​ ​ 7,093 ​ ​ 21,712 Industrial Services (3) ​ ​ — ​ ​ 6,016 ​ ​ 6,016 Small Quantity Generation (4) ​ ​ — ​ ​ 8,189 ​ ​ 8,189 Total Waste Management (5) ​ ​ — ​ ​ 8,714 ​ ​ 8,714 Remediation (6) ​ ​ — ​ ​ 1,726 ​ ​ 1,726 Emergency Response (7) ​ ​ — ​ ​ 3,046 ​ ​ 3,046 Other (9) ​ ​ — ​ ​ 1,125 ​ ​ 1,125 Revenue ​ $ 92,332 ​ $ 38,705 ​ $ 131,037 (1) We categorize our treatment and disposal revenue as either “Base Business” or “Event Business” based on the underlying nature of the revenue source. We define Event Business as non-recurring projects that are expected to equal or exceed 1,000 tons, with Base Business defined as all other business not meeting the definition of Event Business. For the three months ended March 31, 2020 and 2019, 25% and 15% , respectively, of our treatment and disposal revenue was derived from Event Business projects. Base Business revenue accounted for 75% and 85% of our treatment and disposal revenue for the three months ended March 31, 2020 and 2019, respectively. (2) Includes collection and transportation of non-hazardous and hazardous waste. (3) Includes industrial cleaning and maintenance for refineries, chemical plants, steel and automotive plants, marine terminals and refinery services such as tank cleaning and temporary storage. (4) Includes retail services, laboratory packing, less-than-truck-load service and household hazardous waste collection. Contracts for Small Quantity Generation may extend beyond one year and a portion of the transaction price can be fixed. (5) Through our total waste management (“TWM”) program, customers outsource the management of their waste compliance program to us, allowing us to organize and coordinate their waste management disposal activities and environmental compliance. TWM contracts may extend beyond one year and a portion of the transaction price can be fixed. (6) Includes site assessment, onsite treatment, project management and remedial action planning and execution. Contracts for Remediation may extend beyond one year and a portion of the transaction price can be fixed. (7) Includes spill response, waste analysis and treatment and disposal planning. (8) We provide government-mandated, commercial standby oil spill compliance solutions to companies that store, transport, produce or handle petroleum and certain nonpetroleum oils on or near U.S. waters. Our standby services customers pay annual retainer fees under long-term or evergreen contracts for access to our regulatory certifications, specialized assets and highly trained personnel. When a customer with a retainer contract experiences a spill incident, we coordinate and manage the spill response, which results in incremental revenue for the services provided, in addition to the retainer fees. (9) Includes equipment rental and other miscellaneous services. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, 2020 ​ Three Months Ended March 31, 2019 ​ ​ ​ ​ Field & ​ ​ ​ ​ ​ ​ Field & ​ ​ ​ ​ ​ Environmental ​ Industrial ​ ​ ​ ​ Environmental ​ Industrial ​ ​ ​ $s in thousands Services Services Total Services Services Total United States ​ $ 107,928 ​ $ 105,546 ​ $ 213,474 ​ $ 77,359 ​ $ 38,705 ​ $ 116,064 Canada ​ ​ 18,817 ​ ​ 1,077 ​ ​ 19,894 ​ ​ 14,973 ​ ​ — ​ ​ 14,973 EMEA ​ ​ — ​ ​ 5,239 ​ ​ 5,239 ​ ​ — ​ ​ — ​ ​ — Other (1) ​ — ​ 2,113 ​ 2,113 ​ — ​ — ​ — Total revenue ​ $ 126,745 ​ $ 113,975 ​ $ 240,720 ​ $ 92,332 ​ $ 38,705 ​ $ 131,037

BUSINESS COMBINATIONS (Tables)

BUSINESS COMBINATIONS (Tables)	3 Months Ended
	Mar. 31, 2020
Schedule of preliminary fair value of identifiable intangible assets related to the acquisition of NRCG	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, 2020 ​ December 31, 2019 ​ ​ ​ ​ ​ Accumulated ​ ​ ​ ​ ​ ​ ​ Accumulated ​ ​ ​ $s in thousands Cost Amortization Net Cost Amortization Net Amortizing intangible assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Permits, licenses and lease ​ $ 172,668 ​ $ (19,239) ​ $ 153,429 ​ $ 174,339 ​ $ (18,707) ​ $ 155,632 Customer relationships ​ ​ 333,152 ​ ​ (41,781) ​ ​ 291,371 ​ ​ 333,090 ​ ​ (35,254) ​ ​ 297,836 Technology - formulae and processes ​ 6,421 ​ (1,907) ​ 4,514 ​ 6,964 ​ (2,013) ​ 4,951 Customer backlog ​ 3,652 ​ (2,113) ​ 1,539 ​ 3,652 ​ (2,022) ​ 1,630 Tradename ​ 10,390 ​ ​ (5,644) ​ ​ 4,746 ​ ​ 10,390 ​ ​ (4,832) ​ ​ 5,558 Developed software ​ ​ 2,874 ​ ​ (1,936) ​ ​ 938 ​ ​ 2,895 ​ ​ (1,884) ​ ​ 1,011 Non-compete agreements ​ 5,506 ​ (2,372) ​ 3,134 ​ 5,455 ​ (1,694) ​ 3,761 Internet domain and website ​ ​ 536 ​ ​ (163) ​ ​ 373 ​ ​ 536 ​ ​ (156) ​ ​ 380 Database ​ ​ 382 ​ ​ (191) ​ ​ 191 ​ ​ 388 ​ ​ (191) ​ ​ 197 Total amortizing intangible assets ​ 535,581 ​ (75,346) ​ 460,235 ​ 537,709 ​ (66,753) ​ 470,956 Non-amortizing intangible assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Permits and licenses ​ 103,769 ​ ​ — ​ 103,769 ​ 103,816 ​ ​ — ​ 103,816 Tradename ​ 120 ​ ​ — ​ ​ 120 ​ 130 ​ ​ — ​ ​ 130 Total intangible assets ​ $ 639,470 ​ $ (75,346) ​ $ 564,124 ​ $ 641,655 ​ $ (66,753) ​ $ 574,902
NRC
Summary of total merger consideration	​ ​ ​ ​ ​ ​ ​ November 1, $s in thousands 2019 Fair value of US Ecology common stock issued (1) ​ $ 581,101 Fair value of replacement warrants issued (2) ​ 44,858 Fair value of replacement restricted stock units issued (3) ​ 141 Fair value of replacement stock options (4) ​ 360 Repayment of NRC’s term loan and revolving credit facility ​ 398,373 Total merger consideration ​ $ 1,024,833 (1) The fair value of US Ecology common stock issued was calculated based on 9,337,949 shares of US Ecology common stock multiplied by the closing price of US Ecology common stock of $62.23 per share on October 31, 2019, the day immediately preceding the closing of the NRC Merger. (2) The fair value of replacement warrants issued was calculated based on 3,772,753 replacement warrants multiplied by the fair value per warrant of $11.89 . The fair value per warrant was based on the closing price of the replaced NRC warrants (NYSE: NRCG.WS) of $2.33 on October 31, 2019, the day immediately preceding the closing of the NRC Merger, divided by the exchange ratio of 0.196 pursuant to the Merger Agreement. (3) The fair value of replacement restricted stock units issued was calculated based on 118,239 replacement restricted stock units multiplied by the closing price of US Ecology common stock of $62.23 per share on October 31, 2019, the day immediately preceding the closing of the NRC Merger, further multiplied by the ratio of the precombination service period to the remaining vesting period, or approximately 1.9% . (4) The fair value of replacement stock options issued was calculated based on 29,400 replacement stock options multiplied by the fair value per option of $12.26 . The fair value per option was calculated using the Black-Scholes option pricing model, with the following weighted-average assumptions: strike price of $52.30 per option, dividend yield of 1.2% ; expected volatility of 28.9% ; average risk-free interest rate of 1.5% ; and an expected term of 1 year. The replacement stock options became fully vested at the merger date therefore the entire fair value is considered merger consideration.
Summary of preliminary fair value estimates of assets acquired and liabilities assumed	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ ​ ​ March 31, $s in thousands 2019 Adjustments 2020 Current assets ​ $ 131,653 ​ $ — ​ $ 131,653 Property and equipment ​ ​ 197,045 ​ ​ — ​ ​ 197,045 Identifiable intangible assets ​ ​ 303,600 ​ ​ — ​ ​ 303,600 Other assets ​ ​ 41,687 ​ ​ — ​ ​ 41,687 Current liabilities ​ ​ (83,460) ​ ​ (1,215) ​ ​ (84,675) Deferred income tax liabilities ​ ​ (56,596) ​ ​ 194 ​ ​ (56,402) Other liabilities ​ ​ (57,581) ​ ​ — ​ ​ (57,581) Total identifiable net assets ​ ​ 476,348 ​ ​ (1,021) ​ ​ 475,327 Goodwill ​ ​ 548,485 ​ ​ 1,021 ​ ​ 549,506 Total purchase price ​ $ 1,024,833 ​ $ — ​ $ 1,024,833
Schedule of preliminary fair value of identifiable intangible assets related to the acquisition of NRCG	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Average ​ ​ ​ ​ ​ Amortization $s in thousands Fair Value Period (Years) Amortizing intangible assets: ​ ​ ​ ​ ​ Customer relationships - noncontractual ​ $ 193,700 ​ 14 Customer relationships - contractual ​ ​ 34,400 ​ 7 Permits and licenses ​ ​ 8,700 ​ 16 Tradenames ​ ​ 6,100 ​ 2 Non-compete agreements ​ ​ 3,300 ​ 2 Total identified amortizing intangible assets ​ ​ 246,200 ​ ​ Non-amortizing intangible assets: ​ ​ ​ ​ ​ Permits and licenses ​ ​ 57,400 ​ n/a Total identified intangible assets ​ $ 303,600 ​ ​
Schedule of unaudited pro forma financial information	​ ​ ​ ​ ​ ​ ​ (unaudited) ​ ​ Three Months Ended $s in thousands March 31, 2019 Pro forma combined: ​ ​ ​ Revenue ​ ​ 231,195 Net loss ​ ​ (2,857)

ACCUMULATED OTHER COMPREHENSI_2

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Tables)	3 Months Ended
	Mar. 31, 2020
ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS).
Schedule of changes in accumulated other comprehensive income (loss)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Foreign ​ Unrealized Gain ​ ​ ​ ​ ​ Currency ​ (Loss) on Interest ​ ​ ​ $s in thousands Translation Rate Hedge Total Balance at December 31, 2019 ​ $ (10,925) ​ $ (929) ​ $ (11,854) Other comprehensive loss before reclassifications, net of tax ​ (8,259) ​ (6,310) ​ (14,569) Amounts reclassified out of AOCI, net of tax (1) ​ — ​ 212 ​ 212 Other comprehensive loss, net ​ (8,259) ​ (6,098) ​ (14,357) Balance at March 31, 2020 ​ $ (19,184) ​ $ (7,027) ​ $ (26,211) (1) Before-tax reclassifications of $268,000 ($212,000 after-tax) for the three months ended March 31, 2020, were included in Interest expense in the Company’s consolidated statements of operations. Amounts relate to the Company’s interest rate swap which is designated as a cash flow hedge. Changes in fair value of the swap recognized in AOCI are reclassified to interest expense when hedged interest payments on the underlying long-term debt are made or, for terminated swap agreements, amortized to interest expense over the period from termination to original maturity. Amounts in AOCI expected to be reclassified to interest expense over the next 12 months total approximately $516,000 ($407,000 after-tax). ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Foreign ​ Unrealized Gain ​ ​ ​ ​ ​ Currency ​ (Loss) on Interest ​ ​ ​ $s in thousands Translation Rate Hedge Total Balance at December 31, 2018 ​ $ (14,697) ​ $ 906 ​ $ (13,791) Other comprehensive income (loss) before reclassifications, net of tax ​ 1,689 ​ (581) ​ 1,108 Amounts reclassified out of AOCI, net of tax (2) ​ — ​ (110) ​ (110) Other comprehensive income (loss), net ​ 1,689 ​ (691) ​ 998 Balance at March 31, 2019 ​ $ (13,008) ​ $ 215 ​ $ (12,793) (2) Before-tax reclassifications of $139,000 ($110,000 after-tax) for the three months ended March 31, 2019, were included as a reduction of Interest expense in the Company’s consolidated statements of operations. Amounts relate to the Company’s interest rate swap which is designated as a cash flow hedge. Changes in fair value of the swap recognized in AOCI are reclassified to interest expense when hedged interest payments on the underlying long-term debt are made.

RECEIVABLES (Tables)

RECEIVABLES (Tables)	3 Months Ended
	Mar. 31, 2020
RECEIVABLES
Schedule of receivables	​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, ​ December 31, $s in thousands ​ 2020 2019 Trade ​ $ 187,619 ​ $ 196,593 Unbilled revenue ​ 49,854 ​ 54,727 Other ​ 5,959 ​ 7,000 Total receivables ​ 243,432 ​ 258,320 Allowance for doubtful accounts ​ (3,054) ​ (3,010) Receivables, net ​ $ 240,378 ​ $ 255,310

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	3 Months Ended
	Mar. 31, 2020
FAIR VALUE MEASUREMENTS
Schedule of assets and liabilities measured at fair value on a recurring basis	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, 2020 ​ ​ Quoted Prices in ​ Other Observable ​ Unobservable ​ ​ ​ ​ ​ Active Markets ​ Inputs ​ Inputs ​ ​ ​ $s in thousands (Level 1) (Level 2) (Level 3) Total Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed-income securities (1) ​ $ 2,424 ​ $ 1,842 ​ $ — ​ $ 4,266 Money market funds (2) ​ ​ 60,394 ​ ​ — ​ ​ — ​ ​ 60,394 Total ​ $ 62,818 ​ $ 1,842 ​ $ — ​ $ 64,660 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest rate swap agreement (3) ​ $ — ​ $ 9,055 ​ $ — ​ $ 9,055 Contingent consideration (4) ​ ​ — ​ ​ — ​ ​ 6,911 ​ ​ 6,911 Total ​ $ — ​ $ 9,055 ​ $ 6,911 ​ $ 15,966 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ ​ Quoted Prices in ​ Other Observable ​ Unobservable ​ ​ ​ ​ ​ Active Markets ​ Inputs ​ Inputs ​ ​ ​ $s in thousands (Level 1) (Level 2) (Level 3) Total Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed-income securities (1) ​ $ 2,380 ​ $ 1,830 ​ $ — ​ $ 4,210 Money market funds (2) ​ ​ 859 ​ ​ — ​ ​ — ​ ​ 859 Total ​ $ 3,239 ​ $ 1,830 ​ $ — ​ $ 5,069 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest rate swap agreement (3) ​ $ — ​ $ 1,176 ​ $ — ​ $ 1,176 Contingent consideration (4) ​ ​ — ​ ​ — ​ ​ 8,283 ​ ​ 8,283 Total ​ $ — ​ $ 1,176 ​ $ 8,283 ​ $ 9,459 (1) We invest a portion of our Restricted cash and investments in fixed-income securities, including U.S. Treasury and U.S. agency securities. We measure the fair value of U.S. Treasury securities using quoted prices for identical assets in active markets. We measure the fair value of U.S. agency securities using observable market activity for similar assets. The fair value of our fixed-income securities approximates our cost basis in the investments. ​ (2) We invest portions of our Cash and cash equivalents and Restricted cash and investments in money market funds. We measure the fair value of these money market fund investments using quoted prices for identical assets in active markets. The portion of Restricted cash and investments that is invested in money market funds is considered restricted cash for purposes of reconciling the beginning-of-period and end-of-period amounts presented in the Company’s consolidated statements of cash flows. ​ (3) In order to manage interest rate exposure, we entered into an interest rate swap agreement in March 2020 that effectively converts a portion of our variable-rate debt to a fixed interest rate. The swap is designated as a highly-effective cash flow hedge, with gains and losses deferred in other comprehensive income to be recognized as an adjustment to interest expense in the same period that the hedged interest payments affect earnings. The interest rate swap has an effective date of March 31, 2020 in an initial notional amount of $500.0 million. The fair value of the interest rate swap agreement represents the difference in the present value of cash flows calculated (i) at the contracted interest rates and (ii) at current market interest rates at the end of the period. We calculate the fair value of interest rate swap agreements quarterly based on the quoted market price for the same or similar financial instruments. The fair value of the interest rate swap agreement is included in Other long-term liabilities in the Company’s consolidated balance sheet. ​ (4) Our contingent consideration liabilities represent the estimated fair value of potential future payments the Company may be required to remit under the terms of historical purchase agreements entered into by NRC prior to the NRC Merger. The payments are contingent on the acquired businesses’ achievement of annual earnings targets in certain years and other events considered in the purchase agreements. The fair value of our contingent consideration liabilities are calculated using either a Monte Carlo simulation or modified Black-Scholes analyses based on earnings projections for the respective earn-out periods, corresponding earnings thresholds, and approximate timing of payments as outlined in the purchase agreements. The analyses utilize the following assumptions: (i) expected term; (ii) risk-adjusted net sales or earnings; (iii) risk-free interest rate; and (iv) expected volatility of earnings. Estimated payments, as determined through the respective models, are discounted by a credit spread assumption to account for credit risk. At March 31, 2020, the fair value of our contingent consideration liabilities of $5.5 million and $1.4 million were included in Accrued liabilities and Other long-term liabilities, respectively. At December 31, 2019, the fair value of our contingent consideration liabilities of $6.6 million and $1.7 million were included in Accrued liabilities and Other long-term liabilities, respectively. We revalue our contingent consideration payments each period and any increases or decreases to fair value are included in Selling, general and administrative expenses in our consolidated statements of operations. Fair values may be impacted by certain unobservable inputs, most significantly with regard to discount rates, expected volatility and historical and projected performance. Significant changes to these inputs in isolation could result in a significantly different fair value measurement.
Schedule of changes in Level 3 liabilities measured at fair value	​ ​ ​ ​ ​ ​ ​ Three Months Ended $s in thousands March 31, 2020 Contingent consideration, beginning of period ​ $ 8,283 Change in fair value of contingent consideration ​ ​ (1,127) Foreign currency translation ​ ​ (245) Contingent consideration, end of period ​ $ 6,911

PROPERTY AND EQUIPMENT (Tables)

PROPERTY AND EQUIPMENT (Tables)	3 Months Ended
	Mar. 31, 2020
PROPERTY AND EQUIPMENT
Schedule of property and equipment	​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, ​ December 31, $s in thousands ​ 2020 2019 Cell development costs ​ $ 173,787 ​ $ 174,561 Land and improvements ​ 53,004 ​ 52,909 Buildings and improvements ​ 111,539 ​ 109,580 Railcars ​ 17,299 ​ 17,299 Vehicles, vessels and other equipment ​ 324,177 ​ 317,472 Construction in progress ​ 71,740 ​ 61,537 Total property and equipment ​ 751,546 ​ 733,358 Accumulated depreciation and amortization ​ (266,221) ​ (254,590) Property and equipment, net ​ $ 485,325 ​ $ 478,768

LEASES (Tables)

LEASES (Tables)	3 Months Ended
	Mar. 31, 2020
LEASES
Summary of leased assets and liabilities	​ ​ ​ ​ ​ ​ ​ ​ $s in thousands March 31, 2020 December 31, 2019 Assets: ​ ​ ​ ​ ​ ​ Operating right-of-use assets (1) ​ $ 55,843 ​ $ 57,396 Finance right-of-use assets (2) ​ ​ 22,903 ​ ​ 20,499 Total ​ $ 78,746 ​ $ 77,895 ​ ​ ​ ​ ​ ​ ​ Liabilities: ​ ​ ​ ​ ​ ​ Current: ​ ​ ​ ​ ​ ​ Operating (3) ​ $ 17,813 ​ $ 17,317 Finance (4) ​ ​ 4,397 ​ ​ 4,128 Long-term: ​ ​ ​ ​ ​ ​ Operating (5) ​ ​ 38,092 ​ ​ 39,954 Finance (6) ​ ​ 19,098 ​ ​ 16,308 Total ​ $ 79,400 ​ $ 77,707 (1) Included in Operating lease assets in the Company’s consolidated balance sheets. (2) Included in Property and equipment, net in the Company’s consolidated balance sheets. Finance right-of-use assets are recorded net of accumulated amortization of $4.0 million and $2.7 million as of March 31, 2020 and December 31, 2019, respectively. (3) Included in Current portion of operating lease liabilities in the Company’s consolidated balance sheets. (4) Included in Accrued liabilities in the Company’s consolidated balance sheets. (5) Included in Long-term operating lease liabilities in the Company’s consolidated balance sheets. (6) Included in Other long-term liabilities in the Company’s consolidated balance sheets.
Summary of lease cost	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, $s in thousands 2020 2019 Operating lease cost (1) ​ $ 4,999 ​ $ 1,742 Finance lease cost: ​ ​ ​ ​ ​ ​ Amortization of leased assets (2) ​ ​ 1,294 ​ ​ 228 Interest on lease liabilities (3) ​ ​ 318 ​ ​ 20 Total ​ $ 6,611 ​ $ 1,990 (1) Included in Direct operating costs and Selling, general, and administrative expenses in the Company’s consolidated statements of operations. Operating lease cost includes short-term leases, excluding expenses relating to leases with a term of one month or less, which are not material. Operating lease cost excludes variable lease costs which are not material. (2) Included in Direct operating costs in the Company’s consolidated statements of operations. (3) Included in Interest expense in the Company’s consolidated statements of operations.
Schedule of cash flow supplemental information	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, $s in thousands 2020 2019 Cash paid for amounts included in the measurement of lease liabilities: ​ ​ ​ ​ ​ ​ Operating cash flows from operating leases ​ $ 4,851 ​ $ 1,615 Operating cash flows from finance leases ​ $ 318 ​ $ 20 Financing cash flows from finance leases ​ $ 1,128 ​ $ 199 ​ ​ ​ ​ ​ ​ ​ Non-cash investing and financing activities: ​ ​ ​ ​ ​ ​ Right-of-use assets obtained in exchange for new operating lease liabilities ​ $ 2,931 ​ $ 1,628 Right-of-use assets obtained in exchange for new finance lease liabilities ​ $ 4,192 ​ $ 1,844

GOODWILL AND INTANGIBLE ASSETS

GOODWILL AND INTANGIBLE ASSETS (Tables)	3 Months Ended
	Mar. 31, 2020
GOODWILL AND INTANGIBLE ASSETS
Schedule of changes in goodwill	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Field & ​ ​ ​ ​ ​ Environmental ​ Industrial ​ ​ ​ ​ Services ​ Services ​ ​ ​ ​ ​ ​ ​ Accumulated ​ ​ ​ Accumulated ​ ​ ​ $s in thousands Gross Impairment Gross Impairment Total Balance at December 31, 2019 ​ $ 475,271 ​ $ (6,870) ​ $ 298,579 ​ $ — ​ $ 766,980 Impairment charges ​ ​ — ​ ​ (283,600) ​ ​ — ​ ​ (16,700) ​ ​ (300,300) NRC Merger purchase price allocation adjustment ​ ​ 575 ​ ​ — ​ ​ 446 ​ ​ — ​ ​ 1,021 Impact Environmental acquisition ​ ​ — ​ ​ — ​ ​ 300 ​ ​ — ​ ​ 300 Foreign currency translation ​ (1,368) ​ ​ — ​ (602) ​ ​ — ​ (1,970) Balance at March 31, 2020 ​ $ 474,478 ​ $ (290,470) ​ $ 298,723 ​ $ (16,700) ​ $ 466,031
Schedule of intangible assets, net	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, 2020 ​ December 31, 2019 ​ ​ ​ ​ ​ Accumulated ​ ​ ​ ​ ​ ​ ​ Accumulated ​ ​ ​ $s in thousands Cost Amortization Net Cost Amortization Net Amortizing intangible assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Permits, licenses and lease ​ $ 172,668 ​ $ (19,239) ​ $ 153,429 ​ $ 174,339 ​ $ (18,707) ​ $ 155,632 Customer relationships ​ ​ 333,152 ​ ​ (41,781) ​ ​ 291,371 ​ ​ 333,090 ​ ​ (35,254) ​ ​ 297,836 Technology - formulae and processes ​ 6,421 ​ (1,907) ​ 4,514 ​ 6,964 ​ (2,013) ​ 4,951 Customer backlog ​ 3,652 ​ (2,113) ​ 1,539 ​ 3,652 ​ (2,022) ​ 1,630 Tradename ​ 10,390 ​ ​ (5,644) ​ ​ 4,746 ​ ​ 10,390 ​ ​ (4,832) ​ ​ 5,558 Developed software ​ ​ 2,874 ​ ​ (1,936) ​ ​ 938 ​ ​ 2,895 ​ ​ (1,884) ​ ​ 1,011 Non-compete agreements ​ 5,506 ​ (2,372) ​ 3,134 ​ 5,455 ​ (1,694) ​ 3,761 Internet domain and website ​ ​ 536 ​ ​ (163) ​ ​ 373 ​ ​ 536 ​ ​ (156) ​ ​ 380 Database ​ ​ 382 ​ ​ (191) ​ ​ 191 ​ ​ 388 ​ ​ (191) ​ ​ 197 Total amortizing intangible assets ​ 535,581 ​ (75,346) ​ 460,235 ​ 537,709 ​ (66,753) ​ 470,956 Non-amortizing intangible assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Permits and licenses ​ 103,769 ​ ​ — ​ 103,769 ​ 103,816 ​ ​ — ​ 103,816 Tradename ​ 120 ​ ​ — ​ ​ 120 ​ 130 ​ ​ — ​ ​ 130 Total intangible assets ​ $ 639,470 ​ $ (75,346) ​ $ 564,124 ​ $ 641,655 ​ $ (66,753) ​ $ 574,902

DEBT (Tables)

DEBT (Tables)	3 Months Ended
	Mar. 31, 2020
DEBT
Schedule of long-term debt	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, ​ December 31, $s in thousands 2020 2019 Revolving credit facility ​ $ 417,396 ​ $ 327,000 Term loan ​ ​ 448,875 ​ ​ 450,000 Unamortized term loan discount and debt issuance costs ​ ​ (7,514) ​ ​ (7,799) Total debt ​ ​ 858,757 ​ ​ 769,201 Current portion of long-term debt and Short-term borrowings ​ ​ (3,754) ​ ​ (3,359) Long-term debt ​ $ 855,003 ​ $ 765,842
Schedule of interest margins based on the total net leverage ratio	​ ​ ​ ​ Total Net Leverage Ratio LIBOR Rate Loans Interest Margin Base Rate Loans Interest Margin Equal to or greater than 3.25 to 1.00 2.00% 1.00% Equal to or greater than 2.50 to 1.00, but less than 3.25 to 1.00 1.75% 0.75% Equal to or greater than 1.75 to 1.00, but less than 2.50 to 1.00 1.50% 0.50% Equal to or greater than 1.00 to 1.00, but less than 1.75 to 1.00 1.25% 0.25% Less than 1.00 to 1.00 1.00% 0.00%

CLOSURE AND POST-CLOSURE OBLI_2

CLOSURE AND POST-CLOSURE OBLIGATIONS (Tables)	3 Months Ended
	Mar. 31, 2020
CLOSURE AND POST-CLOSURE OBLIGATIONS
Schedule of changes to reported closure and post closure obligations	​ ​ ​ ​ ​ ​ ​ Three Months Ended $s in thousands March 31, 2020 Closure and post-closure obligations, beginning of period ​ $ 86,383 Accretion expense ​ 1,266 Payments ​ (418) Foreign currency translation ​ (135) Closure and post-closure obligations, end of period ​ 87,096 Less current portion ​ (2,704) Long-term portion ​ $ 84,392

EARNINGS (LOSS) PER SHARE (Tabl

EARNINGS (LOSS) PER SHARE (Tables)	3 Months Ended
	Mar. 31, 2020
EARNINGS (LOSS) PER SHARE
Schedule of earnings (loss) per share	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, ​ ​ 2020 ​ 2019 $s and shares in thousands, except per share amounts Basic Diluted Basic Diluted Net (loss) income ​ $ (298,086) ​ $ (298,086) ​ $ 8,043 ​ $ 8,043 Weighted average basic shares outstanding ​ 31,305 ​ 31,305 ​ 21,987 ​ 21,987 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Dilutive effect of share-based awards and warrants ​ ​ ​ ​ — ​ ​ ​ ​ 210 Weighted average diluted shares outstanding ​ ​ ​ ​ 31,305 ​ ​ ​ ​ 22,197 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (Loss) earnings per share ​ $ (9.52) ​ $ (9.52) ​ $ 0.37 ​ $ 0.36 Anti-dilutive shares excluded from calculation ​ ​ ​ ​ 4,131 ​ ​ ​ ​ 79

EQUITY (Tables)

EQUITY (Tables)	3 Months Ended
	Mar. 31, 2020
EQUITY
Summary of PSU, restricted stock and RSU activity	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ PSUs ​ Restricted Stock ​ RSUs ​ ​ ​ ​ Weighted ​ ​ ​ Weighted ​ ​ ​ Weighted ​ ​ ​ ​ Average ​ ​ ​ Average ​ ​ ​ Average ​ ​ ​ ​ Grant Date ​ ​ ​ Grant Date ​ ​ ​ Grant Date ​ Shares Fair Value Shares Fair Value Shares Fair Value Outstanding as of December 31, 2019 42,711 ​ $ 61.11 64,654 ​ $ 55.62 ​ 131,199 ​ $ 59.05 Granted 5,358 ​ ​ 54.55 30,000 ​ ​ 57.04 ​ 108,540 ​ ​ 32.91 Vested (11,500) ​ 62.45 (34,688) ​ 52.43 ​ (41,364) ​ 55.26 Cancelled, expired or forfeited — ​ — — ​ — ​ (8,966) ​ 60.15 Outstanding as of March 31, 2020 36,569 ​ $ 59.73 59,966 ​ $ 58.18 ​ 189,409 ​ $ 44.85
Summary of stock option activity	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ Average ​ ​ ​ ​ Exercise ​ Shares Price Outstanding as of December 31, 2019 293,588 ​ $ 48.23 Granted 67,900 ​ ​ 57.04 Exercised (4,880) ​ 43.13 Cancelled, expired or forfeited (5,415) ​ 42.43 Outstanding as of March 31, 2020 351,193 ​ $ 50.10 Exercisable as of March 31, 2020 240,763 ​ $ 46.52

OPERATING SEGMENTS (Tables)

OPERATING SEGMENTS (Tables)	3 Months Ended
	Mar. 31, 2020
OPERATING SEGMENTS
Summary of financial information of our reportable segments	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, 2020 ​ ​ ​ ​ Field & ​ ​ ​ ​ ​ ​ ​ ​ Environmental ​ Industrial ​ ​ ​ ​ ​ ​ $s in thousands Services Services Corporate Total Revenue ​ $ 126,745 ​ $ 113,975 ​ $ — ​ $ 240,720 Depreciation, amortization and accretion ​ $ 16,042 ​ $ 12,015 ​ $ 628 ​ $ 28,685 Capital expenditures ​ $ 11,532 ​ $ 5,289 ​ $ 2,310 ​ $ 19,131 Total assets ​ $ 997,271 ​ $ 878,774 ​ $ 102,594 ​ $ 1,978,639 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, 2019 ​ ​ ​ ​ Field & ​ ​ ​ ​ ​ ​ ​ ​ Environmental ​ Industrial ​ ​ ​ ​ ​ ​ $s in thousands Services Services Corporate Total Revenue ​ $ 92,332 ​ $ 38,705 ​ $ — ​ $ 131,037 Depreciation, amortization and accretion ​ $ 9,625 ​ $ 2,132 ​ $ 304 ​ $ 12,061 Capital expenditures ​ $ 6,712 ​ $ 178 ​ $ 333 ​ $ 7,223 Total assets ​ $ 703,453 ​ $ 161,299 ​ $ 68,580 ​ $ 933,332
Reconciliation of Net Income to Adjusted EBITDA and adjusted EBITDA by operating segment	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, $s in thousands 2020 2019 Net (loss) income ​ $ (298,086) ​ $ 8,043 Income tax (benefit) expense ​ ​ (263) ​ ​ 3,041 Interest expense ​ ​ 9,310 ​ ​ 4,030 Interest income ​ ​ (89) ​ ​ (207) Foreign currency (gain) loss ​ ​ (937) ​ ​ 139 Other income ​ ​ (171) ​ ​ (110) Property and equipment impairment charges ​ ​ — ​ ​ 25 Goodwill impairment charges ​ ​ 300,300 ​ ​ — Depreciation and amortization of plant and equipment ​ ​ 17,978 ​ ​ 8,125 Amortization of intangible assets ​ ​ 9,441 ​ ​ 2,811 Share-based compensation ​ ​ 1,564 ​ ​ 1,222 Accretion and non-cash adjustment of closure & post-closure liabilities ​ ​ 1,266 ​ ​ 1,125 Gain on property insurance recoveries ​ ​ — ​ ​ (4,653) Business development and integration expenses ​ ​ 2,907 ​ ​ 141 Adjusted EBITDA ​ $ 43,220 ​ $ 23,732 ​ Adjusted EBITDA, by operating segment, is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, $s in thousands ​ 2020 2019 Environmental Services $ 46,124 ​ $ 35,260 Field & Industrial Services 14,478 ​ 2,554 Corporate (17,382) ​ (14,082) Total $ 43,220 ​ $ 23,732
Schedule of long-lived assets by geographic location	​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, ​ December 31, $s in thousands ​ 2020 2019 United States ​ $ 946,125 ​ $ 954,102 Canada ​ 64,383 ​ 70,691 EMEA ​ ​ 22,940 ​ ​ 23,587 Other (1) ​ ​ 16,001 ​ ​ 5,290 Total long-lived assets ​ $ 1,049,449 ​ $ 1,053,670

GENERAL (Details)

GENERAL (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
GENERAL
Operating lease, right-of-use asset	$ 55,843	$ 57,396

GENERAL - NRCG Merger (Details)

GENERAL - NRCG Merger (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Acquisition
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
NRC
Acquisition
Acquisition price	$ 1,024,833	$ 1,024,833

REVENUES (Details)

REVENUES (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2020USD ($)segment	Mar. 31, 2019USD ($)
Disaggregation of revenue
Number of reportable segments | segment	2
Revenue	$ 240,720	$ 131,037
Treatment and disposal
Disaggregation of revenue
Revenue	110,033	80,509
Transportation and Logistics
Disaggregation of revenue
Revenue	32,850	21,712
Industrial Services
Disaggregation of revenue
Revenue	28,478	6,016
Small Quantity Generation
Disaggregation of revenue
Revenue	11,084	8,189
Total Waste Management
Disaggregation of revenue
Revenue	8,482	8,714
Remediation
Disaggregation of revenue
Revenue	10,441	1,726
Emergency Response
Disaggregation of revenue
Revenue	24,922	3,046
Domestic Standby Services
Disaggregation of revenue
Revenue	9,467
Other
Disaggregation of revenue
Revenue	4,963	1,125
Operating Segment | Environmental Services
Disaggregation of revenue
Revenue	126,745	92,332
Operating Segment | Field and Industrial Services
Disaggregation of revenue
Revenue	113,975	38,705
Operating Segment | Treatment and disposal | Environmental Services
Disaggregation of revenue
Revenue	100,049	77,713
Operating Segment | Treatment and disposal | Field and Industrial Services
Disaggregation of revenue
Revenue	9,984	2,796
Operating Segment | Transportation and Logistics | Environmental Services
Disaggregation of revenue
Revenue	26,696	14,619
Operating Segment | Transportation and Logistics | Field and Industrial Services
Disaggregation of revenue
Revenue	6,154	7,093
Operating Segment | Industrial Services | Field and Industrial Services
Disaggregation of revenue
Revenue	28,478	6,016
Operating Segment | Small Quantity Generation | Field and Industrial Services
Disaggregation of revenue
Revenue	11,084	8,189
Operating Segment | Total Waste Management | Field and Industrial Services
Disaggregation of revenue
Revenue	8,482	8,714
Operating Segment | Remediation | Field and Industrial Services
Disaggregation of revenue
Revenue	10,441	1,726
Operating Segment | Emergency Response | Field and Industrial Services
Disaggregation of revenue
Revenue	24,922	3,046
Operating Segment | Domestic Standby Services | Field and Industrial Services
Disaggregation of revenue
Revenue	9,467
Operating Segment | Other | Field and Industrial Services
Disaggregation of revenue
Revenue	$ 4,963	$ 1,125

REVENUES - Treatment and Dispos

REVENUES - Treatment and Disposal Revenue (Details) - Treatment and disposal - T	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Event Business
Disaggregation of revenue
Threshold Tons of Non-recurring projects	1,000
Revenue (in percent)	25.00%	15.00%
Base Business
Disaggregation of revenue
Revenue (in percent)	75.00%	85.00%

REVENUES - Geography (Details)

REVENUES - Geography (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Disaggregation of revenue
Revenue	$ 240,720	$ 131,037
United States
Disaggregation of revenue
Revenue	213,474	116,064
Canada
Disaggregation of revenue
Revenue	19,894	14,973
EMEA
Disaggregation of revenue
Revenue	5,239
Other
Disaggregation of revenue
Revenue	2,113
Operating Segment | Environmental Services
Disaggregation of revenue
Revenue	126,745	92,332
Operating Segment | Environmental Services | United States
Disaggregation of revenue
Revenue	107,928	77,359
Operating Segment | Environmental Services | Canada
Disaggregation of revenue
Revenue	18,817	14,973
Operating Segment | Field and Industrial Services
Disaggregation of revenue
Revenue	113,975	38,705
Operating Segment | Field and Industrial Services | United States
Disaggregation of revenue
Revenue	105,546	$ 38,705
Operating Segment | Field and Industrial Services | Canada
Disaggregation of revenue
Revenue	1,077
Operating Segment | Field and Industrial Services | EMEA
Disaggregation of revenue
Revenue	5,239
Operating Segment | Field and Industrial Services | Other
Disaggregation of revenue
Revenue	$ 2,113

REVENUES - Practical Expedients

REVENUES - Practical Expedients (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
REVENUES
Deferred revenue recognized in revenue	$ 8.4	$ 7.5
Revenue, Practical Expedient, Financing Component	true
Revenue, Practical Expedient, Initial Application and Transition, Nonrestatement of Modified Contract	true

BUSINESS COMBINATIONS - 2020 (D

BUSINESS COMBINATIONS - 2020 (Details) - USD ($)	Jan. 28, 2020	Mar. 31, 2020	Dec. 31, 2019
Acquisition
Goodwill		$ 466,031,000	$ 766,980,000
Impact Environmental Services Inc
Acquisition
Total purchase price	$ 3,300,000
Goodwill		300,000
Field and Industrial Services
Acquisition
Goodwill		298,723,000	298,579,000
Field and Industrial Services | Impact Environmental Services Inc
Acquisition
Goodwill	300,000
Identifiable intangible assets	$ 900,000
Weighted average amortization period	12 years
Amortization period of goodwill recognized and expected to be deductible for income tax purposes	15 years
Environmental Services
Acquisition
Goodwill		$ 474,478,000	$ 475,271,000

BUSINESS COMBINATIONS - Merger

BUSINESS COMBINATIONS - Merger consideration (Details)	Nov. 01, 2019USD ($)Y$ / sharesshares	Mar. 31, 2020USD ($)	Oct. 31, 2019$ / shares
Business Acquisition [Line Items]
Proceeds from term loan		$ 90,000,000
NRC
Business Acquisition [Line Items]
Repayment of NRC's term loan and revolving credit facility	$ 398,373,000
Total merger consideration	1,024,833,000
Transaction fees and expenses	398,400,000
Proceeds from term loan	$ 450,000,000
Term of long term debt	7 years
NRC | Common Stock
Business Acquisition [Line Items]
Fair value of US Ecology common stock issued	$ 581,101,000
Shares Issued | shares	9,337,949
Closing share price | $ / shares			$ 62.23
NRC | Warrants
Business Acquisition [Line Items]
Fair value of replacement warrants issued	$ 44,858,000
Shares Issued | shares	3,772,753
Fair value per warrant | $ / shares	$ 11.89
Closing share price | $ / shares			$ 2.33
Exchange ratio	0.196
NRC | RSUs
Business Acquisition [Line Items]
Fair value of replacement RSUs issued	$ 141,000
Shares Issued | shares	118,239
Ratio of precombination service period to vesting period	1.90%
NRC | Stock options
Business Acquisition [Line Items]
Fair value of replacement stock options	$ 360,000
Shares Issued | shares	29,400
Fair value per option | $ / shares	$ 12.26
Strike price | $ / shares	$ 52.30
NRC | Stock options | Dividend yield
Business Acquisition [Line Items]
Fair value of option	1.2
NRC | Stock options | Expected volatility
Business Acquisition [Line Items]
Fair value of option	28.9
NRC | Stock options | Risk free rate
Business Acquisition [Line Items]
Fair value of option	1.5
NRC | Stock options | Expected term
Business Acquisition [Line Items]
Fair value of option | Y	1

BUSINESS COMBINATIONS - NRCG Me

BUSINESS COMBINATIONS - NRCG Merger (Details) $ in Thousands, $ in Millions	Aug. 01, 2019USD ($)	Aug. 01, 2019CAD ($)	Mar. 31, 2020USD ($)	Mar. 31, 2019USD ($)	Dec. 31, 2019USD ($)	Nov. 01, 2019USD ($)
Acquisition
Payment to acquire business, net of cash acquired			$ 3,309
Consideration paid and the fair value of assets acquired and liabilities assumed
Goodwill			466,031		$ 766,980
Additional information
Revenue since acquisition included in consolidated statements of operations			86,600
Operating loss since acquisition included in consolidated statements of operations			304,000
Acquisition-related costs included in selling, general and administrative expenses			2,907	$ 141
Field and Industrial Services
Consideration paid and the fair value of assets acquired and liabilities assumed
Goodwill			298,723		298,579
NRC
Acquisition
Acquisition price			1,024,833		1,024,833
Consideration paid and the fair value of assets acquired and liabilities assumed
Current assets			131,653		131,653
Property and equipment			197,045		197,045
Identifiable intangible assets			303,600		303,600
Other assets			41,687		41,687
Current liabilities			(84,675)		(83,460)
Other liabilities			(57,581)		(57,581)
Total identifiable net assets			475,327		476,348
Goodwill			549,506		548,485	$ 549,500
Total purchase price			1,024,833		$ 1,024,833
Adjustments
Current liabilities - adjustments			1,215
Deferred income tax liabilities - adjustments			(194)
Total identifiable net assets - adjustment			(1,021)
Goodwill - adjustment			1,021
Pro forma combined:
Revenue				231,195
Net loss				$ (2,857)
NRC | Field and Industrial Services
Consideration paid and the fair value of assets acquired and liabilities assumed
Goodwill						$ 240,100
Adjustments
Goodwill - adjustment			$ 446
US Ecology Sarnia
Acquisition
Percentage of outstanding shares acquired	100.00%
Acquisition price	$ 17,900	$ 23.5
Consideration paid and the fair value of assets acquired and liabilities assumed
Identifiable intangible assets	6,200
Goodwill	7,700
Total purchase price	$ 17,900	$ 23.5
Additional information
Weighted average amortization period	14 years	14 years

BUSINESS COMBINATIONS - Prelimi

BUSINESS COMBINATIONS - Preliminary fair value estimates of assets acquired and liabilities assumed recognized (Details) $ in Millions	Jan. 28, 2020USD ($)	Aug. 01, 2019USD ($)	Aug. 01, 2019CAD ($)	Mar. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Nov. 01, 2019USD ($)
Consideration paid and the fair value of assets acquired and liabilities assumed
Goodwill				$ 466,031,000	$ 766,980,000
Goodwill impairment charge				300,300,000
Field and Industrial Services
Consideration paid and the fair value of assets acquired and liabilities assumed
Goodwill				298,723,000	298,579,000
Goodwill impairment charge				16,700,000
Environmental Services
Consideration paid and the fair value of assets acquired and liabilities assumed
Goodwill				474,478,000	475,271,000
Goodwill impairment charge				283,600,000
Impact Environmental Services Inc
Consideration paid and the fair value of assets acquired and liabilities assumed
Goodwill				300,000
Total purchase price	$ 3,300,000
Impact Environmental Services Inc | Field and Industrial Services
Consideration paid and the fair value of assets acquired and liabilities assumed
Identifiable intangible assets	900,000
Goodwill	$ 300,000
NRC
Consideration paid and the fair value of assets acquired and liabilities assumed
Current assets				131,653,000	131,653,000
Property and equipment				197,045,000	197,045,000
Identifiable intangible assets				303,600,000	303,600,000
Other assets				41,687,000	41,687,000
Current liabilities				(84,675,000)	(83,460,000)
Deferred income tax liabilities				(56,402,000)	(56,596,000)
Other liabilities				(57,581,000)	(57,581,000)
Total identifiable net assets				475,327,000	476,348,000
Goodwill				549,506,000	548,485,000	$ 549,500,000
Total purchase price				1,024,833,000	$ 1,024,833,000
Goodwill expected to be deductible for income tax purposes						33,300,000
Adjustments
Current liabilities - adjustments				1,215,000
Deferred income tax liabilities - adjustments				(194,000)
Total identifiable net assets - adjustment				(1,021,000)
Goodwill - adjustment				1,021,000
NRC | Field and Industrial Services
Consideration paid and the fair value of assets acquired and liabilities assumed
Goodwill						240,100,000
Adjustments
Goodwill - adjustment				446,000
NRC | Environmental Services
Consideration paid and the fair value of assets acquired and liabilities assumed
Goodwill						$ 309,400,000
Adjustments
Goodwill - adjustment				$ 575,000
US Ecology Sarnia
Consideration paid and the fair value of assets acquired and liabilities assumed
Identifiable intangible assets		$ 6,200,000
Goodwill		7,700,000
Total purchase price		$ 17,900,000	$ 23.5

BUSINESS COMBINATIONS - preli_2

BUSINESS COMBINATIONS - preliminary fair value of identifiable intangible assets (Details) - NRC $ in Thousands	Nov. 01, 2019USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total identified intangible assets	$ 246,200
Total identified intangible assets	303,600
Customer relationships - noncontractual
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total identified intangible assets	$ 193,700
Average Amortization Period	14 years
Customer relationships - contractual
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total identified intangible assets	$ 34,400
Average Amortization Period	7 years
Permits and licenses
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total identified intangible assets	$ 8,700
Average Amortization Period	16 years
Tradename
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total identified intangible assets	$ 6,100
Average Amortization Period	2 years
Non-compete agreements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total identified intangible assets	$ 3,300
Average Amortization Period	2 years
Permits and licenses
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-amortizing intangible assets	$ 57,400

BUSINESS COMBINATIONS - Pro for

BUSINESS COMBINATIONS - Pro forma information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Additional information
Revenue since acquisition included in consolidated statements of operations	$ 86,600
Operating loss since acquisition included in consolidated statements of operations	304,000
Acquisition-related costs included in selling, general and administrative expenses	$ 2,907	$ 141
NRC
Pro forma combined:
Revenue		231,195
Net loss		$ (2,857)

BUSINESS COMBINATIONS - Other 2

BUSINESS COMBINATIONS - Other 2019 (Details) $ in Thousands, $ in Millions	Aug. 01, 2019USD ($)	Aug. 01, 2019CAD ($)	Mar. 31, 2020USD ($)	Mar. 31, 2019USD ($)	Dec. 31, 2019USD ($)
Acquisition
Payment to acquire business, net of cash acquired			$ 3,309
Consideration paid and the fair value of assets acquired and liabilities assumed
Goodwill			466,031		$ 766,980
Additional information
Revenue since acquisition included in consolidated statements of operations			86,600
Operating loss since acquisition included in consolidated statements of operations			304,000
Acquisition-related costs included in selling, general and administrative expenses			2,907	$ 141
Field and Industrial Services
Consideration paid and the fair value of assets acquired and liabilities assumed
Goodwill			$ 298,723		$ 298,579
US Ecology Sarnia
Acquisition
Percentage of outstanding shares acquired	100.00%
Acquisition price	$ 17,900	$ 23.5
Consideration paid and the fair value of assets acquired and liabilities assumed
Identifiable intangible assets	6,200
Goodwill	7,700
Total purchase price	$ 17,900	$ 23.5
Additional information
Weighted average amortization period	14 years	14 years

ACCUMULATED OTHER COMPREHENSI_3

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) - Changes in AOCI (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Accumulated other comprehensive income (loss)
Beginning balances	$ 1,011,380	$ 359,217
Ending balances	676,323	363,492
Foreign Currency Translation
Accumulated other comprehensive income (loss)
Beginning balances	(10,925)	(14,697)
Other comprehensive income (loss) before reclassifications, net of tax	(8,259)	1,689
Other comprehensive income, (loss), net	(8,259)	1,689
Ending balances	(19,184)	(13,008)
Unrealized Gain (Loss) on Interest Rate Hedge
Accumulated other comprehensive income (loss)
Beginning balances	(929)	906
Other comprehensive income (loss) before reclassifications, net of tax	(6,310)	(581)
Amounts reclassified out of AOCI, net of tax	212	(110)
Other comprehensive income, (loss), net	(6,098)	(691)
Ending balances	(7,027)	215
Accumulated Other Comprehensive Income (Loss)
Accumulated other comprehensive income (loss)
Beginning balances	(11,854)	(13,791)
Other comprehensive income (loss) before reclassifications, net of tax	(14,569)	1,108
Amounts reclassified out of AOCI, net of tax	212	(110)
Other comprehensive income, (loss), net	(14,357)	998
Ending balances	$ (26,211)	$ (12,793)

ACCUMULATED OTHER COMPREHENSI_4

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) -Reclassifications Line Items (Details) - USD ($)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Reclassification adjustments
Interest expense	$ 9,310,000	$ 4,030,000
Unrealized Gain (Loss) on Interest Rate Hedge | Interest rate swap agreement
Reclassification adjustments
Amounts in AOCI expected to be recognized over the next 12 months before tax	516,000
Amounts in AOCI expected to be recognized over the next 12 months, net of taxes	407,000
Unrealized Gain (Loss) on Interest Rate Hedge | Interest rate swap agreement | Reclassification out of accumulated other comprehensive income
Reclassification adjustments
Interest expense	268,000	139,000
Interest expense, net of tax	$ 212,000	$ 110,000

RECEIVABLES (Details)

RECEIVABLES (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
RECEIVABLES
Trade	$ 187,619	$ 196,593
Unbilled revenue	49,854	54,727
Other	5,959	7,000
Total receivables	243,432	258,320
Allowance for doubtful accounts	(3,054)	(3,010)
Receivables, net	$ 240,378	$ 255,310

FAIR VALUE MEASUREMENTS (Detail

FAIR VALUE MEASUREMENTS (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	Sep. 19, 2019
Assets measured at fair value on a recurring basis
Initial notional amount	$ 500,000
Equity securities without readily determinable fair value
Investment in privately held company			$ 7,900
Interest rate swap agreement
Assets measured at fair value on a recurring basis
Initial notional amount	500,000
Other Observable Inputs (Level 2) | Variable-rate debt
Equity securities without readily determinable fair value
Variable rate	433,200
Level 3 | Contingent Consideration | Accrued Liabilities
Assets measured at fair value on a recurring basis
Liabilities fair value disclosure	5,500	$ 6,600
Level 3 | Contingent Consideration | Other long-term liabilities
Assets measured at fair value on a recurring basis
Liabilities fair value disclosure	1,400	1,700
Recurring
Assets measured at fair value on a recurring basis
Assets fair value disclosure	64,660	5,069
Liabilities fair value disclosure	15,966	9,459
Recurring | Interest rate swap agreement
Assets measured at fair value on a recurring basis
Liabilities fair value disclosure	9,055	1,176
Recurring | Fixed-income securities
Assets measured at fair value on a recurring basis
Assets fair value disclosure	4,266	4,210
Recurring | Money market funds
Assets measured at fair value on a recurring basis
Assets fair value disclosure	60,394	859
Recurring | Contingent Consideration
Assets measured at fair value on a recurring basis
Liabilities fair value disclosure	6,911	8,283
Recurring | Quoted Prices in Active Markets (Level 1)
Assets measured at fair value on a recurring basis
Assets fair value disclosure	62,818	3,239
Recurring | Quoted Prices in Active Markets (Level 1) | Fixed-income securities
Assets measured at fair value on a recurring basis
Assets fair value disclosure	2,424	2,380
Recurring | Quoted Prices in Active Markets (Level 1) | Money market funds
Assets measured at fair value on a recurring basis
Assets fair value disclosure	60,394	859
Recurring | Other Observable Inputs (Level 2)
Assets measured at fair value on a recurring basis
Assets fair value disclosure	1,842	1,830
Liabilities fair value disclosure	9,055	1,176
Recurring | Other Observable Inputs (Level 2) | Interest rate swap agreement
Assets measured at fair value on a recurring basis
Liabilities fair value disclosure	9,055	1,176
Recurring | Other Observable Inputs (Level 2) | Fixed-income securities
Assets measured at fair value on a recurring basis
Assets fair value disclosure	1,842	1,830
Recurring | Level 3
Assets measured at fair value on a recurring basis
Liabilities fair value disclosure	6,911	8,283
Recurring | Level 3 | Contingent Consideration
Assets measured at fair value on a recurring basis
Liabilities fair value disclosure	$ 6,911	$ 8,283

FAIR VALUE MEASUREMENTS - Chang

FAIR VALUE MEASUREMENTS - Changes in Level 3 liabilities measured at fair value (Details) - Level 3 - Recurring $ in Thousands	3 Months Ended
	Mar. 31, 2020USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Balance at beginning of period	$ 8,283
Change in fair value of contingent consideration	(1,127)
Foreign currency translation	(245)
Balance at end of period	$ 6,911

PROPERTY AND EQUIPMENT (Details

PROPERTY AND EQUIPMENT (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
PROPERTY AND EQUIPMENT
Total property and equipment	$ 751,546		$ 733,358
Accumulated depreciation and amortization	(266,221)		(254,590)
Property and equipment, net	485,325		478,768
Depreciation and amortization of plant and equipment	17,978	$ 8,125
Cell development costs
PROPERTY AND EQUIPMENT
Total property and equipment	173,787		174,561
Land and improvements
PROPERTY AND EQUIPMENT
Total property and equipment	53,004		52,909
Buildings and improvements
PROPERTY AND EQUIPMENT
Total property and equipment	111,539		109,580
Railcars
PROPERTY AND EQUIPMENT
Total property and equipment	17,299		17,299
Vehicles, vessels and other equipment
PROPERTY AND EQUIPMENT
Total property and equipment	324,177		317,472
Construction in progress
PROPERTY AND EQUIPMENT
Total property and equipment	$ 71,740		$ 61,537

LEASES (Details)

LEASES (Details)	3 Months Ended
	Mar. 31, 2020
Leases
Operating lease - existence of option to renew	true
Finance lease - existence of option to renew	true
Minimum
Leases
Operating lease - term	1 year
Finance lease - term	1 year
Maximum
Leases
Operating lease - term	15 years
Operating lease - renewal term	40 years
Finance lease - term	15 years
Finance lease - renewal term	40 years

LEASES - Leased assets and liab

LEASES - Leased assets and liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Assets:
Operating lease assets	$ 55,843	$ 57,396
Finance right-of-use lease assets	22,903	20,499
Total	78,746	77,895
Finance leased assets - accumulated amortization	4,000	2,700
Liabilities:
Operating lease, current	17,813	17,317
Finance lease, current	4,397	4,128
Long-term operating lease liabilities	38,092	39,954
Finance lease, long term	19,098	16,308
Total	$ 79,400	$ 77,707

LEASES - Lease cost (Details)

LEASES - Lease cost (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Lease cost
Operating lease cost	$ 4,999	$ 1,742
Amortization of leased assets	1,294	228
Interest on lease liabilities	318	20
Total	$ 6,611	$ 1,990

LEASES - Supplemental Cash Flow

LEASES - Supplemental Cash Flow information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
LEASES
Operating cash flows from operating leases	$ 4,851	$ 1,615
Operating cash flows from finance leases	318	20
Financing cash flows from finance leases	1,128	199
Right-of-use assets obtained in exchange for new operating lease liabilities	2,931	1,628
Right-of-use assets obtained in exchange for new finance lease liabilities	$ 4,192	$ 1,844

GOODWILL AND INTANGIBLE ASSET_2

GOODWILL AND INTANGIBLE ASSETS - Goodwill (Details) - USD ($)	3 Months Ended
	Mar. 31, 2020	Jan. 28, 2020	Dec. 31, 2019	Nov. 01, 2019	Aug. 01, 2019
Changes in goodwill
Balance at the beginning of the period	$ 766,980,000
Foreign currency translation	(1,970,000)
Balance at the end of the period	466,031,000
Accumulated Impairment
Impairment charges	(300,300,000)
NRC
Changes in goodwill
Balance at the beginning of the period	548,485,000
Purchase price allocation adjustment	1,021,000
Balance at the end of the period	549,506,000
Identifiable intangible assets	303,600,000		$ 303,600,000
Total identified intangible assets				$ 246,200,000
Impact Environmental Services Inc
Changes in goodwill
Acquisition	300,000
Balance at the end of the period	300,000
US Ecology Sarnia
Changes in goodwill
Identifiable intangible assets					$ 6,200,000
Environmental Services
Changes in goodwill
Balance at the beginning of the period	475,271,000
Foreign currency translation	(1,368,000)
Balance at the end of the period	474,478,000
Accumulated Impairment
Accumulated impairment at the beginning	(6,870,000)
Impairment charges	(283,600,000)
Accumulated impairment at the ending	(290,470,000)
Environmental Services | NRC
Changes in goodwill
Purchase price allocation adjustment	575,000
Field and Industrial Services
Changes in goodwill
Balance at the beginning of the period	298,579,000
Foreign currency translation	(602,000)
Balance at the end of the period	298,723,000
Accumulated Impairment
Impairment charges	(16,700,000)
Accumulated impairment at the ending	(16,700,000)
Field and Industrial Services | NRC
Changes in goodwill
Purchase price allocation adjustment	$ 446,000
Field and Industrial Services | Impact Environmental Services Inc
Changes in goodwill
Identifiable intangible assets		$ 900,000

GOODWILL AND INTANGIBLE ASSET_3

GOODWILL AND INTANGIBLE ASSETS (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Goodwill [Line Items]
Impairment charges	$ 300,300
Goodwill	466,031	$ 766,980
Impairment charges of finite-lived assets	0
EWDS
Goodwill [Line Items]
Impairment charges	283,600
Goodwill	25,800
International reporting unit
Goodwill [Line Items]
Impairment charges	16,700
Goodwill	$ 1,600

GOODWILL AND INTANGIBLE ASSET_4

GOODWILL AND INTANGIBLE ASSETS - Intangible Assets (Details) - USD ($)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Jan. 28, 2020	Dec. 31, 2019	Aug. 01, 2019
Intangible Assets
Amortizing intangible assets, Cost	$ 535,581,000			$ 537,709,000
Accumulated amortization	(75,346,000)			(66,753,000)
Amortizing intangible assets, Net	460,235,000			470,956,000
Total intangible assets, cost	639,470,000			641,655,000
Total intangible assets, net	564,124,000			574,902,000
Amortization of intangible assets	9,441,000	$ 2,811,000
Goodwill	466,031,000			766,980,000
Permits and licenses
Intangible Assets
Non-amortizing intangible assets	103,769,000			103,816,000
Tradename
Intangible Assets
Non-amortizing intangible assets	120,000			130,000
Permits, licenses and lease
Intangible Assets
Amortizing intangible assets, Cost	172,668,000			174,339,000
Accumulated amortization	(19,239,000)			(18,707,000)
Amortizing intangible assets, Net	153,429,000			155,632,000
Customer relationships
Intangible Assets
Amortizing intangible assets, Cost	333,152,000			333,090,000
Accumulated amortization	(41,781,000)			(35,254,000)
Amortizing intangible assets, Net	291,371,000			297,836,000
Technology - formulae and processes
Intangible Assets
Amortizing intangible assets, Cost	6,421,000			6,964,000
Accumulated amortization	(1,907,000)			(2,013,000)
Amortizing intangible assets, Net	4,514,000			4,951,000
Customer backlog
Intangible Assets
Amortizing intangible assets, Cost	3,652,000			3,652,000
Accumulated amortization	(2,113,000)			(2,022,000)
Amortizing intangible assets, Net	1,539,000			1,630,000
Tradename
Intangible Assets
Amortizing intangible assets, Cost	10,390,000			10,390,000
Accumulated amortization	(5,644,000)			(4,832,000)
Amortizing intangible assets, Net	4,746,000			5,558,000
Developed software
Intangible Assets
Amortizing intangible assets, Cost	2,874,000			2,895,000
Accumulated amortization	(1,936,000)			(1,884,000)
Amortizing intangible assets, Net	938,000			1,011,000
Non-compete agreements
Intangible Assets
Amortizing intangible assets, Cost	5,506,000			5,455,000
Accumulated amortization	(2,372,000)			(1,694,000)
Amortizing intangible assets, Net	3,134,000			3,761,000
Internet domain and website
Intangible Assets
Amortizing intangible assets, Cost	536,000			536,000
Accumulated amortization	(163,000)			(156,000)
Amortizing intangible assets, Net	373,000			380,000
Database
Intangible Assets
Amortizing intangible assets, Cost	382,000			388,000
Accumulated amortization	(191,000)			(191,000)
Amortizing intangible assets, Net	191,000			197,000
Impact Environmental Services Inc
Intangible Assets
Amortizing intangible assets, Cost	900,000
Goodwill	300,000
US Ecology Sarnia
Intangible Assets
Goodwill					$ 7,700,000
Environmental Services
Intangible Assets
Goodwill	474,478,000			475,271,000
Field and Industrial Services
Intangible Assets
Goodwill	$ 298,723,000			$ 298,579,000
Field and Industrial Services | Impact Environmental Services Inc
Intangible Assets
Goodwill			$ 300,000

DEBT - Schedule (Details)

DEBT - Schedule (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Long-term debt
Unamortized discount and debt issuance costs	$ (7,514)	$ (7,799)
Total debt	858,757	769,201
Current portion of long-term debt and Short-term borrowings	(3,754)	(3,359)
Long-term debt	855,003	765,842
Credit agreement
Long-term debt
Loan amount	417,396	327,000
Term Loan
Long-term debt
Loan amount	$ 448,875	$ 450,000

DEBT - Paragraph (Details)

DEBT - Paragraph (Details) $ in Thousands	Nov. 01, 2019USD ($)	Aug. 06, 2019	Apr. 18, 2017USD ($)	Mar. 31, 2020USD ($)	Mar. 31, 2020USD ($)	Dec. 31, 2019USD ($)
DEBT
Notional amount				$ 500,000	$ 500,000
Interest rate swap agreement
DEBT
Notional amount				$ 500,000	500,000
Percentage of outstanding debt				58.00%
Net loss related to terminated swap				$ 1,800
Sweep Arrangements
DEBT
Advances outstanding				396	396
Credit agreement
DEBT
Maximum borrowing capacity			$ 500,000
Loan amount				$ 417,396	$ 417,396	$ 327,000
Contractual term			5 years
Accordion feature	$ 250,000		$ 200,000
Percentage of EBITDA plus certain additional amounts used to determine additional borrowing capacity	100.00%
Effective interest rate (as a percent)				3.96%	3.96%
Availability for borrowings under line of credit				$ 75,900	$ 75,900
Equity interest in domestic subsidiaries pledged as security (as a percent)			100.00%
Voting equity interest in foreign subsidiaries pledged as security (as a percent)			65.00%
Non-voting equity interest in foreign subsidiaries pledged as security (as a percent)			100.00%
Minimum consolidated senior secured leverage ratio			3
Total leverage ratio		4	4
Credit agreement | Minimum
DEBT
Commitment fee (as a percent)					0.175%
Credit agreement | Maximum
DEBT
Commitment fee (as a percent)					0.35%
Credit agreement | Equal To Or Greater Than 3.25 to 1.00
DEBT
Minimum consolidated senior secured leverage ratio			3.25
Credit agreement | Equal To Or Greater Than 2.50 to 1.00, But Less Than 3.25 to 1.00
DEBT
Minimum consolidated senior secured leverage ratio			2.50
Maximum consolidated senior secured leverage ratio			3.25
Credit agreement | Equal To Or Greater Than 1.75 to 1.00, But Less Than 2.50 to 1.00
DEBT
Minimum consolidated senior secured leverage ratio			1.75
Maximum consolidated senior secured leverage ratio			2.50
Credit agreement | Equal To Or Greater Than 1.00 to 1.00, But Less Than 1.75 to 1.00
DEBT
Minimum consolidated senior secured leverage ratio			1
Maximum consolidated senior secured leverage ratio			1.75
Credit agreement | Less Than 1.00 to 1.00
DEBT
Maximum consolidated senior secured leverage ratio			1
Credit agreement | LIBOR | Equal To Or Greater Than 3.25 to 1.00
DEBT
Percentage points added to the reference rate			2.00%
Credit agreement | LIBOR | Equal To Or Greater Than 2.50 to 1.00, But Less Than 3.25 to 1.00
DEBT
Percentage points added to the reference rate			1.75%
Credit agreement | LIBOR | Equal To Or Greater Than 1.75 to 1.00, But Less Than 2.50 to 1.00
DEBT
Percentage points added to the reference rate			1.50%
Credit agreement | LIBOR | Equal To Or Greater Than 1.00 to 1.00, But Less Than 1.75 to 1.00
DEBT
Percentage points added to the reference rate			1.25%
Credit agreement | LIBOR | Less Than 1.00 to 1.00
DEBT
Percentage points added to the reference rate			1.00%
Credit agreement | Base rate | Equal To Or Greater Than 3.25 to 1.00
DEBT
Percentage points added to the reference rate			1.00%
Credit agreement | Base rate | Equal To Or Greater Than 2.50 to 1.00, But Less Than 3.25 to 1.00
DEBT
Percentage points added to the reference rate			0.75%
Credit agreement | Base rate | Equal To Or Greater Than 1.75 to 1.00, But Less Than 2.50 to 1.00
DEBT
Percentage points added to the reference rate			0.50%
Credit agreement | Base rate | Equal To Or Greater Than 1.00 to 1.00, But Less Than 1.75 to 1.00
DEBT
Percentage points added to the reference rate			0.25%
Credit agreement | Base rate | Less Than 1.00 to 1.00
DEBT
Percentage points added to the reference rate			0.00%
Credit Agreement, Letter Of Credit
DEBT
Maximum borrowing capacity			$ 75,000
Line of credit issued in the form of a standby letters of credit				6,700	$ 6,700
Credit Agreement, Swingline Loans
DEBT
Maximum borrowing capacity	$ 40,000		$ 40,000
Credit Agreement, Swingline Loans | Sweep Arrangements
DEBT
Maximum borrowing capacity				40,000	40,000
Incremental Term Loans
DEBT
Increase in capacity	50,000
Maximum borrowing capacity	$ 450,000
Loan amount				$ 400,000	$ 400,000
Contractual term	7 years
Required annual principal repayment (as a percent)	1.00%
Effective interest rate (as a percent)				4.39%	4.39%
Incremental Term Loans | LIBOR
DEBT
Percentage points added to the reference rate	2.25%
Incremental Term Loans | LIBOR | Step Up Rate Based on Credit Ratings
DEBT
Percentage points added to the reference rate	2.50%
Incremental Term Loans | Base rate
DEBT
Percentage points added to the reference rate	1.25%
Incremental Term Loans | Base rate | Step Up Rate Based on Credit Ratings
DEBT
Percentage points added to the reference rate	1.50%

CLOSURE AND POST-CLOSURE OBLI_3

CLOSURE AND POST-CLOSURE OBLIGATIONS - Rollforward (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Changes to reported closure and post-closure obligations
Closure and post-closure obligations, beginning of period	$ 86,383
Accretion expense	1,266	$ 1,125
Payments	(418)
Foreign currency translation	(135)
Closure and post-closure obligations, end of period	87,096
Less current portion	(2,704)		$ (2,152)
Long-term portion	$ 84,392		$ 84,231

INCOME TAXES (Details)

INCOME TAXES (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
INCOME TAXES
Effective tax rate (as a percent)	0.10%	27.40%
Unrecognized Tax Benefits	$ 8,400		$ 8,300
Possible reduction in the provision for income taxes if the unrecognized tax benefits were recognized	300
Penalties accrued on unrecognized tax benefits	0
Change in net operating losses deferred tax asset	$ (8,100)

EARNINGS (LOSS) PER SHARE (Deta

EARNINGS (LOSS) PER SHARE (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
EARNINGS (LOSS) PER SHARE
Net (loss) income	$ (298,086)	$ 8,043
Basic
Weighted average basic shares outstanding	31,305	21,987
Earnings per share-Basic (in dollars per share)	$ (9.52)	$ 0.37
Diluted
Net income, diluted	$ (298,086)	$ 8,043
Dilutive effect of share-based awards and warrants (in shares)		210
Weighted average diluted shares outstanding	31,305	22,197
(Loss) earnings per share-Diluted (in dollars per share)	$ (9.52)	$ 0.36
Anti-dilutive shares excluded from calculation	4,131	79

EQUITY - Stock Repurchase Progr

EQUITY - Stock Repurchase Program (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Dec. 30, 2019	Jun. 01, 2016
Repurchase of Common Stock
Authorized repurchase amount of outstanding common stock		$ 25	$ 25
Common stock repurchase program
Repurchase of Common Stock
Repurchase of common stock (in shares)	397,600
Repurchase of common stock value	$ 17.3

EQUITY - Omnibus Incentive Plan

EQUITY - Omnibus Incentive Plan (Details) - Omnibus Plan - shares	Mar. 31, 2020	May 27, 2015
Stock-Based Compensation Plans
Number of shares authorized for grant		1,500,000
Number of shares available for future grant	540,801

EQUITY - PSUs, Restricted Stock

EQUITY - PSUs, Restricted Stock and RSU (Details) - $ / shares	Jan. 24, 2020	Mar. 31, 2020	Dec. 31, 2019
Weighted Average Grant Date Fair Value
Common stock, shares issued		31,503,000	31,461,000
PSUs
Stock-Based Compensation Plans
Number of common shares each PSU represents (in shares)	1
Shares
Outstanding at the beginning of the year (in shares)		42,711
Granted (in shares)	5,358	5,358
Vested (in shares)		(11,500)
Outstanding at the end of the year (in shares)		36,569
Weighted Average Grant Date Fair Value
Outstanding at the beginning of the period (in dollars per share)		$ 61.11
Granted (in dollars per share)	$ 54.55	54.55
Vested (in dollars per share)		62.45
Outstanding at the end of the period (in dollars per share)		$ 59.73
Common stock, shares issued		6,797
Restricted stock
Shares
Outstanding at the beginning of the year (in shares)		64,654
Granted (in shares)		30,000
Vested (in shares)		(34,688)
Outstanding at the end of the year (in shares)		59,966
Weighted Average Grant Date Fair Value
Outstanding at the beginning of the period (in dollars per share)		$ 55.62
Granted (in dollars per share)		57.04
Vested (in dollars per share)		52.43
Outstanding at the end of the period (in dollars per share)		$ 58.18
RSUs
Shares
Outstanding at the beginning of the year (in shares)		131,199
Granted (in shares)		108,540
Vested (in shares)		(41,364)
Cancelled, expired or forfeited (in shares)		(8,966)
Outstanding at the end of the year (in shares)		189,409
Weighted Average Grant Date Fair Value
Outstanding at the beginning of the period (in dollars per share)		$ 59.05
Granted (in dollars per share)		32.91
Vested (in dollars per share)		55.26
Cancelled, expired or forfeited (in dollars per share)		60.15
Outstanding at the end of the period (in dollars per share)		$ 44.85

EQUITY - Stock Options (Details

EQUITY - Stock Options (Details)	3 Months Ended
	Mar. 31, 2020$ / sharesshares
Additional disclosures
Number of options exercised via net share settlement	3,738
Stock options
Shares
Outstanding at the beginning of the period (in shares)	293,588
Granted (in shares)	67,900
Exercised (in shares)	(4,880)
Cancelled, expired or forfeited (in shares)	(5,415)
Outstanding at the end of the period (in shares)	351,193
Exercisable at the end of the period (in shares)	240,763
Weighted Average Exercise Price
Outstanding at the beginning of the period (in dollars per share) | $ / shares	$ 48.23
Granted (in dollars per share) | $ / shares	57.04
Exercised (in dollars per share) | $ / shares	43.13
Cancelled, expired or forfeited (in dollars per share) | $ / shares	42.43
Outstanding at the end of the period (in dollars per share) | $ / shares	50.10
Exercisable at the end of the period (in dollars per share) | $ / shares	$ 46.52

EQUITY - Treasury Stock (Detail

EQUITY - Treasury Stock (Details) - $ / shares	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Dividends
Dividends paid per share (in dollars per share)	$ 0.18	$ 0.18
Share repurchase program related to net share settlement
Treasury Stock
Repurchase of common stock (in shares)	17,169
Average cost of repurchase (in dollars per share)	$ 57.91
Common stock repurchase program
Treasury Stock
Repurchase of common stock (in shares)	397,600
Average cost of repurchase (in dollars per share)	$ 43.61

COMMITMENTS AND CONTINGENCIES -

COMMITMENTS AND CONTINGENCIES - Litigation and Regulatory Proceedings (Details) $ in Thousands	Jan. 10, 2020USD ($)	Mar. 31, 2020USD ($)	Mar. 31, 2019USD ($)	Nov. 17, 2018employee
Litigation and Regulatory Proceedings
Insurance proceeds from damaged property and equipment			$ 5,000
Property insurance recoveries			$ 4,653
Explosion at the Grand View, Idaho Facility
Litigation and Regulatory Proceedings
Number of fatalities | employee				1
Continued limited operations insurance recoveries		$ 462
Occupational Safety and Health Review Commission
Litigation and Regulatory Proceedings
Settlement	$ 50

OPERATING SEGMENTS - Summarized

OPERATING SEGMENTS - Summarized Financial Information (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2020USD ($)segment	Mar. 31, 2019USD ($)	Dec. 31, 2019USD ($)
OPERATING SEGMENTS
Number of reportable segments | segment	2
Revenue	$ 240,720	$ 131,037
Depreciation, amortization and accretion	28,685	12,061
Capital expenditures	19,131	7,223
Total assets	1,978,639	933,332	$ 2,231,244
Treatment and disposal
OPERATING SEGMENTS
Revenue	110,033	80,509
Transportation and Logistics
OPERATING SEGMENTS
Revenue	32,850	21,712
Remediation
OPERATING SEGMENTS
Revenue	10,441	1,726
Other
OPERATING SEGMENTS
Revenue	4,963	1,125
Corporate
OPERATING SEGMENTS
Depreciation, amortization and accretion	628	304
Capital expenditures	2,310	333
Total assets	102,594	68,580
Environmental Services | Operating Segment
OPERATING SEGMENTS
Revenue	126,745	92,332
Depreciation, amortization and accretion	16,042	9,625
Capital expenditures	11,532	6,712
Total assets	997,271	703,453
Environmental Services | Operating Segment | Treatment and disposal
OPERATING SEGMENTS
Revenue	100,049	77,713
Environmental Services | Operating Segment | Transportation and Logistics
OPERATING SEGMENTS
Revenue	26,696	14,619
Field and Industrial Services | Operating Segment
OPERATING SEGMENTS
Revenue	113,975	38,705
Depreciation, amortization and accretion	12,015	2,132
Capital expenditures	5,289	178
Total assets	878,774	161,299
Field and Industrial Services | Operating Segment | Treatment and disposal
OPERATING SEGMENTS
Revenue	9,984	2,796
Field and Industrial Services | Operating Segment | Transportation and Logistics
OPERATING SEGMENTS
Revenue	6,154	7,093
Field and Industrial Services | Operating Segment | Remediation
OPERATING SEGMENTS
Revenue	10,441	1,726
Field and Industrial Services | Operating Segment | Other
OPERATING SEGMENTS
Revenue	$ 4,963	$ 1,125

OPERATING SEGMENTS - Reconcilia

OPERATING SEGMENTS - Reconciliation of EBITDA (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Reconciliation of Net Income to Adjusted EBITDA
Net (loss) income	$ (298,086)	$ 8,043
Income tax (benefit) expense	(263)	3,041
Interest expense	9,310	4,030
Interest income	(89)	(207)
Foreign currency (gain) loss	(937)	139
Other income	(171)	(110)
Property and equipment impairment charges		25
Goodwill impairment charges	300,300
Depreciation and amortization of plant and equipment	17,978	8,125
Amortization of intangibles assets	9,441	2,811
Share-based compensation	1,564	1,222
Accretion and non-cash adjustment of closure & post-closure liabilities	1,266	1,125
Gain on property insurance recoveries		(4,653)
Business development and integration expenses	2,907	141
Adjusted EBITDA	43,220	23,732
Operating Segment | Environmental Services
Reconciliation of Net Income to Adjusted EBITDA
Adjusted EBITDA	46,124	35,260
Operating Segment | Field and Industrial Services
Reconciliation of Net Income to Adjusted EBITDA
Adjusted EBITDA	14,478	2,554
Corporate
Reconciliation of Net Income to Adjusted EBITDA
Adjusted EBITDA	$ (17,382)	$ (14,082)

OPERATING SEGMENTS - Revenue an

OPERATING SEGMENTS - Revenue and Long-lived Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Revenue and Long-Lived Assets Outside of the United States
Total long- lived assets	$ 1,049,449	$ 1,053,670
United States
Revenue and Long-Lived Assets Outside of the United States
Total long- lived assets	946,125	954,102
Canada
Revenue and Long-Lived Assets Outside of the United States
Total long- lived assets	64,383	70,691
EMEA
Revenue and Long-Lived Assets Outside of the United States
Total long- lived assets	22,940	23,587
Other
Revenue and Long-Lived Assets Outside of the United States
Total long- lived assets	$ 16,001	$ 5,290