US Ecology (ECOL) 10-Q 29 Apr 22 2022 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2022	Apr. 27, 2022
Document Information
Document Type	10-Q
Document Quarterly Report	true
Document Transition Report	false
Document Period End Date	Mar. 31, 2022
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		31,512,324
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q1
Entity Central Index Key	0001783400
Amendment Flag	false
Common Stock
Document Information
Title of 12(b) Security	Common Stock, par value $0.01 per share
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, 2022	Dec. 31, 2021
Current Assets:
Cash and cash equivalents	$ 74,186	$ 67,487
Receivables, net	248,233	250,154
Prepaid expenses and other current assets	30,012	32,136
Income taxes receivable	7,961	14,441
Total current assets	360,392	364,218
Property and equipment, net	455,041	456,384
Operating right-of-use assets	54,884	43,607
Restricted cash and investments	1,532	1,567
Intangible assets, net	482,127	489,573
Goodwill	413,526	413,126
Other assets	51,171	36,923
Total assets	1,818,673	1,805,398
Current Liabilities:
Accounts payable	63,933	64,793
Deferred revenue	19,903	15,950
Accrued liabilities	47,589	51,265
Accrued salaries and benefits	26,061	29,438
Income taxes payable	231	559
Current portion of long-term debt	3,359	3,359
Current portion of closure and post-closure obligations	6,322	5,771
Current portion of operating lease liabilities	17,780	15,799
Total current liabilities	185,178	186,934
Long-term debt	734,285	735,125
Long-term closure and post-closure obligations	93,332	93,149
Long-term operating lease liabilities	37,991	28,477
Other long-term liabilities	12,947	13,907
Deferred income taxes, net	123,702	123,482
Total liabilities	1,187,435	1,181,074
Commitments and contingencies (See Note 15)
Stockholders' Equity:
Common stock $0.01 par value per share, 50,000 authorized; 31,512 shares issued and outstanding	315	315
Additional paid-in capital	818,707	821,970
Retained deficit	(192,136)	(183,115)
Treasury stock, at cost, 141 and 242 shares, respectively	(6,177)	(10,652)
Accumulated other comprehensive income (loss)	10,529	(4,194)
Total stockholders' equity	631,238	624,324
Total liabilities and stockholders' equity	$ 1,818,673	$ 1,805,398

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares shares in Thousands	Mar. 31, 2022	Dec. 31, 2021
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	31,512	31,512
Common stock, shares outstanding	31,512	31,512
Treasury stock, shares	141	242

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
CONSOLIDATED STATEMENTS OF OPERATIONS
Revenue	$ 240,980	$ 228,619
Direct operating costs	187,567	175,746
Gross profit	53,413	52,873
Selling, general and administrative expenses	57,336	51,368
Operating (loss) income	(3,923)	1,505
Other income (expense):
Interest income	229	273
Interest expense	(6,821)	(7,357)
Foreign currency loss	(698)	(371)
Other	177	3,710
Total other expense	(7,113)	(3,745)
Loss before income taxes	(11,036)	(2,240)
Income tax benefit	(2,014)	(1,444)
Net loss	$ (9,022)	$ (796)
Loss per share:
Basic	$ (0.29)	$ (0.03)
Diluted	$ (0.29)	$ (0.03)
Shares used in loss per share calculation:
Basic	31,208	31,104
Diluted	31,208	31,104

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME
Net loss	$ (9,022)	$ (796)
Other comprehensive income:
Foreign currency translation gain	1,469	1,439
Net changes in interest rate hedge, net of taxes of $3,523 and $2,450, respectively	13,254	9,217
Comprehensive income, net of tax	$ 5,701	$ 9,860

CONSOLIDATED STATEMENTS OF CO_2

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Other comprehensive income:
Net changes in interest rate hedge, tax	$ 3,523	$ 2,450

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Cash flows from operating activities:
Net loss	$ (9,022)	$ (796)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization of property and equipment	16,900	18,234
Amortization of intangible assets	7,872	9,135
Accretion of closure and post-closure obligations	1,227	1,182
Unrealized foreign currency gain	(852)	(315)
Deferred income taxes	(3,467)	(3,781)
Share-based compensation expense	1,948	1,928
Share-based payments of business development and integration expenses	120	163
Unrecognized tax benefits	13	12
Net gain on disposition of assets	(245)	(221)
Amortization of debt issuance costs	589	577
Amortization of debt discount	40	40
Change in fair value of minority interest investment		(3,509)
Changes in assets and liabilities:
Receivables	3,865	(680)
Income taxes receivable	6,514	1,276
Other assets	1,106	1,114
Accounts payable and accrued liabilities	(4,155)	(3,647)
Deferred revenue	3,917	2,214
Accrued salaries and benefits	(3,407)	(3,028)
Income taxes payable	(329)	(98)
Closure and post-closure obligations	(517)	(337)
Net cash provided by operating activities	22,117	19,463
Cash flows from investing activities:
Purchases of property and equipment	(16,180)	(9,614)
Proceeds from sale of property and equipment	438	1,623
Minority interest investment		(712)
Proceeds from sale of short-term investments	1,932
Purchases of restricted investments		(913)
Proceeds from sale of restricted investments		934
Net cash used in investing activities	(13,810)	(8,682)
Cash flows from financing activities:
Proceeds from short-term borrowings	1,959	3,227
Payments on short-term borrowings	(1,959)	(2,950)
Payments on long-term debt	(1,125)	(1,125)
Payment of equipment financing obligations	(1,218)	(1,461)
Repurchase of common stock	(12)	(465)
Net cash used in financing activities	(2,355)	(2,774)
Effect of foreign exchange rate changes on cash	712	708
Increase in Cash and cash equivalents and restricted cash	6,664	8,715
Cash and cash equivalents and restricted cash at beginning of period	69,054	75,104
Cash and cash equivalents and restricted cash at end of period	$ 75,718	$ 83,819

CONSOLIDATED STATEMENTS OF CA_2

CONSOLIDATED STATEMENTS OF CASH FLOWS (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Supplemental Disclosures:
Income taxes (received) paid, net	$ (4,746)	$ 1,270
Interest paid	6,198	6,404
Non-cash investing and financing activities:
Capital expenditures in accounts payable	6,789	4,569
Restricted common stock and common stock issued from treasury shares	$ 4,487	$ 4,127

CONSOLIDATED STATEMENTS OF CA_3

CONSOLIDATED STATEMENTS OF CASH FLOWS - (Restricted cash and investments) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021	Dec. 31, 2020
Reconciliation of Cash and cash equivalents and restricted cash:
Cash and cash equivalents	$ 74,186	$ 67,487	$ 82,354	$ 73,848
Restricted cash	1,532	1,567	1,465	1,256
Cash and cash equivalents and restricted cash	$ 75,718	$ 69,054	$ 83,819	$ 75,104

CONSOLIDATED STATEMENTS OF STOC

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Common Stock	Additional Paid-In Capital	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Income (Loss)	Total
Beginning balances at Dec. 31, 2020	$ 315	$ 820,567	$ (188,452)	$ (15,841)	$ (14,658)	$ 601,931
Increase (Decrease) in Stockholders' Equity
Net loss			(796)			(796)
Other comprehensive income					10,656
Share-based compensation		1,928
Share-based payments of business development and integration expenses		161
Other			(1)
Repurchase of common stock				(465)
Issuance of restricted common stock and common stock from treasury shares		(4,838)		4,127
Ending balances at Mar. 31, 2021	315	817,818	(189,249)	(12,179)	(4,002)	612,703
Beginning balances at Dec. 31, 2021	315	821,970	(183,115)	(10,652)	(4,194)	$ 624,324
Balance (in shares) at Dec. 31, 2021						31,512
Increase (Decrease) in Stockholders' Equity
Net loss			(9,022)			$ (9,022)
Other comprehensive income					14,723
Share-based compensation		1,948
Share-based payments of business development and integration expenses		120
Other			1
Repurchase of common stock				(12)
Issuance of restricted common stock and common stock from treasury shares		(5,331)		4,487
Ending balances at Mar. 31, 2022	$ 315	$ 818,707	$ (192,136)	$ (6,177)	$ 10,529	$ 631,238
Balance (in shares) at Mar. 31, 2022						31,512

GENERAL

GENERAL	3 Months Ended
	Mar. 31, 2022
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, 2021. The results of operations for the three months ended March 31, 2022 are not necessarily indicative of the results to be expected for the entire year ending December 31, 2022. ​ The Company’s consolidated balance sheet as of December 31, 2021 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 March 2020, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2020-04, “Facilitation of the Effects of Reference Rate Reform on Financial Reporting” (Topic 848). The ASU provides optional expedients and exceptions for applying GAAP to transactions affected by reference rate (e.g., LIBOR) reform if certain criteria are met, for a limited period of time to ease the potential burden in accounting for (or recognizing the effects of) reference rate reform on financial reporting. The ASU is effective as of March 12, 2020 through December 31, 2022. We will evaluate transactions or contract modifications occurring as a result of reference rate reform and determine whether to apply the optional guidance on an ongoing basis. The ASU is currently not expected to have a material impact on our consolidated financial statements. ​ Republic Services, Inc. Merger Agreement On February 8, 2022, we entered into the previously disclosed Agreement and Plan of Merger (the “Merger Agreement”) with Republic Services, Inc., a Delaware corporation (“Republic”) and Bronco Acquisition Corp., a Delaware corporation and a wholly-owned subsidiary of Republic (“Merger Sub”). The Merger Agreement provides that, upon the terms and subject to the conditions set forth in the Merger Agreement, Merger Sub will merge with and into the Company (the “Merger”), with the Company continuing as the surviving corporation and as a wholly-owned subsidiary of Republic. The foregoing description of the Merger Agreement is a summary only and is qualified in its entirety by reference to the complete text of the Merger Agreement filed as Exhibit 2.1 in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2021. On March 30, 2022 the waiting period under Hart Scott-Rodino Anitrust Improvements Act of 1976, as amended, expired with respect to the Merger, and on April 26, 2022 we held a Special Meeting of the stockholders of the Company wherein we received the necessary affirmative vote to consummate the Merger. The transaction is currently expected to close on May 2, 2022.

REVENUES

REVENUES	3 Months Ended
	Mar. 31, 2022
REVENUES
REVENUES	NOTE 2. REVENUES ​ Effective in the second quarter of 2021, we made changes to the manner in which we evaluate revenues associated with our various response-based services, including emergency response, standby services and remediation. As a result, revenues from Emergency Response and Domestic Standby Services, which were formerly presented as discrete service lines, are now combined and presented as a single “Emergency Response” service line and certain revenues formerly classified as Domestic Standby Services are now classified as Remediation. Throughout this Quarterly Report on Form 10-Q, our disaggregated revenues for all periods presented have been recast to reflect these changes. ​ The following table presents our revenue disaggregated by our reportable segments and service lines: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, 2022 ​ ​ Waste ​ Field ​ Energy ​ ​ ​ $s in thousands Solutions Services ​ Waste Total Treatment & Disposal Revenue (1) ​ $ 96,280 ​ $ 10,781 ​ $ 7,104 ​ $ 114,165 Services Revenue: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Transportation and Logistics (2) ​ ​ 18,486 ​ ​ 7,273 ​ ​ 4,384 ​ ​ 30,143 Industrial Services (3) ​ ​ — ​ ​ 28,870 ​ ​ 972 ​ ​ 29,842 Small Quantity Generation (4) ​ ​ — ​ ​ 15,039 ​ ​ — ​ ​ 15,039 Total Waste Management (5) ​ ​ — ​ ​ 10,589 ​ ​ — ​ ​ 10,589 Remediation (6) ​ ​ — ​ ​ 5,360 ​ ​ — ​ ​ 5,360 Emergency Response (7) ​ ​ — ​ ​ 31,416 ​ ​ — ​ ​ 31,416 Other (8) ​ ​ — ​ ​ 2,995 ​ ​ 1,431 ​ ​ 4,426 Revenue ​ $ 114,766 ​ $ 112,323 ​ $ 13,891 ​ $ 240,980 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, 2021 ​ ​ Waste ​ Field ​ Energy ​ ​ ​ $s in thousands Solutions Services ​ Waste Total Treatment & Disposal Revenue (1) ​ $ 88,060 ​ $ 9,977 ​ $ 3,783 ​ $ 101,820 Services Revenue: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Transportation and Logistics (2) ​ ​ 16,082 ​ ​ 6,329 ​ ​ 1,401 ​ ​ 23,812 Industrial Services (3) ​ ​ — ​ ​ 26,256 ​ ​ 409 ​ ​ 26,665 Small Quantity Generation (4) ​ ​ — ​ ​ 13,052 ​ ​ — ​ ​ 13,052 Total Waste Management (5) ​ ​ — ​ ​ 9,882 ​ ​ — ​ ​ 9,882 Remediation (6) ​ ​ — ​ ​ 11,975 ​ ​ — ​ ​ 11,975 Emergency Response (7) ​ ​ — ​ ​ 37,355 ​ ​ — ​ ​ 37,355 Other (8) ​ ​ — ​ ​ 3,423 ​ ​ 635 ​ ​ 4,058 Revenue ​ $ 104,142 ​ $ 118,249 ​ $ 6,228 ​ $ 228,619 (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, 2022 and 2021, 20% and 24% , respectively, of our treatment and disposal revenue was derived from Event Business projects. Base Business revenue accounted for 80% and 76% of our treatment and disposal revenue for the three months ended March 31, 2022 and 2021, 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 services such as spill response, waste analysis and treatment and disposal planning as well as government-mandated, commercial standby oil spill compliance solutions and services that we provide 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. (8) 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, 2022 ​ Three Months Ended March 31, 2021 ​ ​ Waste ​ Field ​ Energy ​ ​ ​ ​ Waste ​ Field ​ Energy ​ ​ ​ $s in thousands Solutions Services Waste Total Solutions Services Waste Total United States ​ $ 97,142 ​ $ 104,440 ​ $ 13,891 ​ $ 215,473 ​ $ 84,474 ​ $ 106,051 ​ $ 6,228 ​ $ 196,753 Canada ​ ​ 17,624 ​ ​ 592 ​ ​ — ​ ​ 18,216 ​ ​ 19,668 ​ ​ 579 ​ ​ — ​ ​ 20,247 EMEA ​ ​ — ​ ​ 6,264 ​ ​ — ​ ​ 6,264 ​ ​ — ​ ​ 10,018 ​ ​ — ​ ​ 10,018 Other (1) ​ — ​ 1,027 ​ — ​ 1,027 ​ — ​ 1,601 ​ — ​ 1,601 Total revenue ​ $ 114,766 ​ $ 112,323 ​ $ 13,891 ​ $ 240,980 ​ $ 104,142 ​ $ 118,249 ​ $ 6,228 ​ $ 228,619 (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. Revenue is recognized when these services are performed. During the three months ended March 31, 2022 and 2021, we recognized $13.5 million and $10.7 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.

ACCUMULATED OTHER COMPREHENSIVE

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)	3 Months Ended
	Mar. 31, 2022
ACCUMULATED OTHER COMPREHENSIVE LOSS
ACCUMULATED OTHER COMPREHENSIVE LOSS	NOTE 3. 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, 2021 ​ $ (9,375) ​ $ 5,181 ​ $ (4,194) Other comprehensive income before reclassifications, net of tax ​ 1,469 ​ 12,746 ​ 14,215 Amounts reclassified out of AOCI, net of tax (1) ​ — ​ 508 ​ 508 Other comprehensive income, net ​ 1,469 ​ 13,254 ​ 14,723 Balance at March 31, 2022 ​ $ (7,906) ​ $ 18,435 ​ $ 10,529 (1) Before-tax reclassifications of $642,000 ($508,000 after-tax) for the three months ended March 31, 2022, 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 $1.2 million ($927,000 after-tax). ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Foreign ​ Unrealized Gain ​ ​ ​ ​ ​ Currency ​ (Loss) on Interest ​ ​ ​ $s in thousands Translation Rate Hedge Total Balance at December 31, 2020 ​ $ (7,870) ​ $ (6,788) ​ $ (14,658) Other comprehensive income before reclassifications, net of tax ​ 1,439 ​ 8,323 ​ 9,762 Amounts reclassified out of AOCI, net of tax (2) ​ — ​ 894 ​ 894 Other comprehensive income, net ​ 1,439 ​ 9,217 ​ 10,656 Balance at March 31, 2021 ​ $ (6,431) ​ $ 2,429 ​ $ (4,002) (2) Before-tax reclassifications of $1.1 million ($894,000 after-tax) for the three months ended March 31, 2021, 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.

CONCENTRATIONS AND CREDIT RISK

CONCENTRATIONS AND CREDIT RISK	3 Months Ended
	Mar. 31, 2022
CONCENTRATIONS AND CREDIT RISK
CONCENTRATIONS AND CREDIT RISK	NOTE 4. CONCENTRATIONS AND CREDIT RISK ​ Major Customers ​ No customer accounted for more than 10% of total revenue for the three months ended March 31, 2022 or 2021, respectively. No customer accounted for more than 10% of total trade receivables as of March 31, 2022 or December 31, 2021. ​ 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 may be 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. As of March 31, 2022, 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, 2022
RECEIVABLES
RECEIVABLES	NOTE 5. RECEIVABLES ​ Receivables consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, ​ December 31, $s in thousands ​ 2022 2021 Trade ​ $ 186,906 ​ $ 183,747 Unbilled revenue ​ 60,513 ​ 62,029 Other ​ 3,834 ​ 7,421 Total receivables ​ 251,253 ​ 253,197 Allowance for credit losses ​ (3,020) ​ (3,043) Receivables, net ​ $ 248,233 ​ $ 250,154 ​

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS	3 Months Ended
	Mar. 31, 2022
FAIR VALUE MEASUREMENTS
FAIR VALUE MEASUREMENTS	NOTE 6. 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 and interest rate swap agreements. 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. In each of September 2019 and March 2021, the Company invested $7.9 million and $712,000, respectively, in the preferred stock of a privately held company. 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. In March 2021, in connection with our incremental investment of $712,000, we observed that the fair value of our initial investment of $7.9 million increased by $3.5 million and, accordingly, recognized a gain on our minority interest investment of $3.5 million. The fair value of our minority interest investment is included in Other assets in the Company’s consolidated balance sheets. Changes in the fair value of our minority interest investment are included in Other income in the Company’s consolidated statements of operations. As of March 31, 2022, there have been no other 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, 2022, the fair value of the Company’s variable rate term loan was estimated to be $438.5 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’s assets and liabilities measured at fair value on a recurring basis consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, 2022 ​ ​ Quoted Prices in ​ Other Observable ​ Unobservable ​ ​ ​ ​ ​ Active Markets ​ Inputs ​ Inputs ​ ​ ​ $s in thousands (Level 1) (Level 2) (Level 3) Total Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Money market funds (2) ​ ​ 1,597 ​ ​ — ​ ​ — ​ ​ 1,597 Interest rate swap agreement (3) ​ ​ — ​ ​ 21,900 ​ ​ — ​ ​ 21,900 Total ​ $ 1,597 ​ $ 21,900 ​ $ — ​ $ 23,497 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2021 ​ ​ 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) ​ $ 1,695 ​ $ 255 ​ $ — ​ $ 1,950 Money market funds (2) ​ ​ 1,886 ​ ​ — ​ ​ — ​ ​ 1,886 Interest rate swap agreement (3) ​ ​ — ​ ​ 5,022 ​ ​ — ​ ​ 5,022 Total ​ $ 3,581 ​ $ 5,277 ​ $ — ​ $ 8,858 (1) We had short-term investments in fixed-income securities, including U.S. Treasury and U.S. agency securities as of December 31, 2021. We measured the fair value of U.S. Treasury securities using quoted prices for identical assets in active markets. We measured the fair value of U.S. agency securities using observable market activity for similar assets. The fair value of our fixed-income securities approximated 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-year and end-of-year 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 assets in the Company’s consolidated balance sheets as of March 31, 2022 and December 31, 2021, respectively.

PROPERTY AND EQUIPMENT

PROPERTY AND EQUIPMENT	3 Months Ended
	Mar. 31, 2022
PROPERTY AND EQUIPMENT
PROPERTY AND EQUIPMENT	NOTE 7. PROPERTY AND EQUIPMENT ​ Property and equipment consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, ​ December 31, $s in thousands ​ 2022 2021 Cell development costs ​ $ 204,067 ​ $ 203,217 Land and improvements ​ 74,524 ​ 74,298 Buildings and improvements ​ 137,204 ​ 138,659 Railcars ​ 17,299 ​ 17,299 Vehicles, vessels and other equipment ​ 352,925 ​ 350,950 Construction in progress ​ 65,798 ​ 54,609 Total property and equipment ​ 851,817 ​ 839,032 Accumulated depreciation and amortization ​ (396,776) ​ (382,648) Property and equipment, net ​ $ 455,041 ​ $ 456,384 ​ Depreciation and amortization expense for the three months ended March 31, 2022 and 2021 was $16.9 million and $18.2 million, respectively.

LEASES

LEASES	3 Months Ended
	Mar. 31, 2022
LEASES
LEASES	NOTE 8. 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 lease up ​ 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: ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, ​ December 31, $s in thousands 2022 2021 Assets: ​ ​ ​ ​ ​ ​ Operating right-of-use assets (1) ​ $ 54,884 ​ $ 43,607 Finance right-of-use assets (2) ​ ​ 15,788 ​ ​ 17,290 Total ​ $ 70,672 ​ $ 60,897 ​ ​ ​ ​ ​ ​ ​ Liabilities: ​ ​ ​ ​ ​ ​ Current: ​ ​ ​ ​ ​ ​ Operating (3) ​ $ 17,780 ​ $ 15,799 Finance (4) ​ ​ 4,778 ​ ​ 4,969 Long-term: ​ ​ ​ ​ ​ ​ Operating (5) ​ ​ 37,991 ​ ​ 28,477 Finance (6) ​ ​ 11,119 ​ ​ 12,108 Total ​ $ 71,668 ​ $ 61,353 (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 $14.6 million and $13.3 million as of March 31, 2022 and December 31, 2021, 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 2022 2021 Operating lease cost (1) ​ $ 5,123 ​ $ 5,296 Finance lease cost: ​ ​ ​ ​ ​ ​ Amortization of leased assets (2) ​ ​ 1,295 ​ ​ 1,334 Interest on lease liabilities (3) ​ ​ 265 ​ ​ 278 Total ​ $ 6,683 ​ $ 6,908 (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 2022 2021 Cash paid for amounts included in the measurement of lease liabilities: ​ ​ ​ ​ ​ ​ Operating cash flows from operating leases ​ $ 4,905 ​ $ 5,151 Operating cash flows from finance leases ​ $ 265 ​ $ 278 Financing cash flows from finance leases ​ $ 1,180 ​ $ 1,192 ​ ​ ​ ​ ​ ​ ​ Non-cash investing and financing activities: ​ ​ ​ ​ ​ ​ Right-of-use assets obtained in exchange for new operating lease liabilities ​ $ 16,054 ​ $ 2,074 ​

GOODWILL AND INTANGIBLE ASSETS

GOODWILL AND INTANGIBLE ASSETS	3 Months Ended
	Mar. 31, 2022
GOODWILL AND INTANGIBLE ASSETS
GOODWILL AND INTANGIBLE ASSETS	NOTE 9. GOODWILL AND INTANGIBLE ASSETS ​ Changes in goodwill for the three months ended March 31, 2022 consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Waste Solutions ​ Field Services ​ Energy Waste ​ ​ ​ ​ ​ ​ ​ Accumulated ​ ​ ​ Accumulated ​ ​ ​ Accumulated ​ ​ ​ $s in thousands Gross Impairment Gross Impairment Gross Impairment Total Balance at December 31, 2021 ​ $ 166,925 ​ $ (6,870) ​ $ 237,368 ​ $ (19,900) ​ $ 399,503 ​ $ (363,900) ​ $ 413,126 Foreign currency translation ​ 278 ​ ​ — ​ 122 ​ ​ — ​ ​ — ​ ​ — ​ 400 Balance at March 31, 2022 ​ $ 167,203 ​ $ (6,870) ​ $ 237,490 ​ $ (19,900) ​ $ 399,503 ​ $ (363,900) ​ $ 413,526 ​ Intangible assets, net consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, 2022 ​ December 31, 2021 ​ ​ ​ ​ ​ Accumulated ​ ​ ​ ​ ​ ​ ​ Accumulated ​ ​ ​ $s in thousands Cost Amortization Net Cost Amortization Net Amortizing intangible assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Permits, licenses and lease ​ $ 175,299 ​ $ (28,331) ​ $ 146,968 ​ $ 174,959 ​ $ (27,170) ​ $ 147,789 Customer relationships ​ ​ 340,215 ​ ​ (94,542) ​ ​ 245,673 ​ ​ 340,065 ​ ​ (87,952) ​ ​ 252,113 Technology - formulae and processes ​ 7,277 ​ (2,628) ​ 4,649 ​ 7,166 ​ (2,531) ​ 4,635 Customer backlog ​ 3,652 ​ (2,843) ​ 809 ​ 3,652 ​ (2,752) ​ 900 Tradename ​ 10,390 ​ ​ (10,390) ​ ​ — ​ 10,390 ​ ​ (10,390) ​ ​ — Developed software ​ ​ 2,907 ​ ​ (2,552) ​ ​ 355 ​ ​ 2,903 ​ ​ (2,475) ​ ​ 428 Non-compete agreements ​ 5,583 ​ (5,256) ​ 327 ​ 5,573 ​ (5,211) ​ 362 Internet domain and website ​ ​ 536 ​ ​ (220) ​ ​ 316 ​ ​ 536 ​ ​ (213) ​ ​ 323 Database ​ ​ 391 ​ ​ (241) ​ ​ 150 ​ ​ 390 ​ ​ (235) ​ ​ 155 Total amortizing intangible assets ​ 546,250 ​ (147,003) ​ 399,247 ​ 545,634 ​ (138,929) ​ 406,705 Non-amortizing intangible assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Permits and licenses ​ 82,744 ​ ​ — ​ 82,744 ​ 82,734 ​ ​ — ​ 82,734 Tradename ​ 136 ​ ​ — ​ ​ 136 ​ 134 ​ ​ — ​ ​ 134 Total intangible assets ​ $ 629,130 ​ $ (147,003) ​ $ 482,127 ​ $ 628,502 ​ $ (138,929) ​ $ 489,573 ​ Amortization expense for the three months ended March 31, 2022 and 2021 was $7.9 million and $9.1 million, respectively. Foreign intangible asset carrying amounts are affected by foreign currency translation.

DEBT

DEBT	3 Months Ended
	Mar. 31, 2022
DEBT
DEBT	NOTE 10. DEBT ​ Long-term debt consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, ​ December 31, $s in thousands 2022 2021 Revolving credit facility ​ $ 303,000 ​ $ 303,000 Term loan ​ ​ 439,875 ​ ​ 441,000 Unamortized term loan discount and debt issuance costs ​ ​ (5,231) ​ ​ (5,516) Total debt ​ ​ 737,644 ​ ​ 738,484 Current portion of long-term debt ​ ​ (3,359) ​ ​ (3,359) Long-term debt ​ $ 734,285 ​ $ 735,125 ​ 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 (as amended, restated, supplemented or otherwise modified through the date hereof, 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 initially provided for a $500.0 million, five-year revolving credit facility (the “Revolving Credit Facility”). ​ On August 6, 2019, Predecessor US Ecology entered into the first amendment (the “First Amendment”) to the Credit Agreement. 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 (as defined in the Credit Agreement) 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 London Inter-Bank Offered Rate (“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, 2022, the effective interest rate on the term loan, including the impact of the amortization of debt issuance costs, was 2.91%. ​ On June 26, 2020, Predecessor US Ecology entered into the third amendment (the “Third Amendment”) to the Credit Agreement. Among other things, the Third Amendment amended the Credit Agreement to provide a covenant relief period through the earlier of March 31, 2022 and the date Predecessor US Ecology elects to end such covenant relief period pursuant to the terms therein. During the covenant relief period, the Third Amendment increased Predecessor US Ecology’s consolidated total net leverage ratio requirement as of the end of each fiscal quarter to certain ratios above the 4.00 to 1.00 ratio in effect immediately before giving effect to the Third Amendment, subject to compliance with certain restrictions on restricted payments and permitted acquisitions during such covenant relief period. ​ On June 29, 2021, Predecessor US Ecology entered into the fourth amendment (the “Fourth Amendment”) to the Credit Agreement. Among other things, the Fourth Amendment amended the Credit Agreement to extend the maturity date for the existing revolving credit facility to June 29, 2026 (or such earlier date as the revolving credit facility may otherwise terminate pursuant to the terms of the Credit Agreement). The Fourth Amendment also amended the Credit Agreement (i) to extend the existing covenant relief period to end on the earlier of December 31, 2022 and the date Predecessor US Ecology elects to end such covenant relief period pursuant to the terms therein and (ii) to permanently increase Predecessor US Ecology’s consolidated total net leverage ratio requirement as of the end of each fiscal quarter ending on and after December 31, 2022 to 4.50 to 1.00. During the covenant relief period until the fiscal quarter ending December 31, 2022, the Fourth Amendment increased Predecessor US Ecology’s consolidated total net leverage ratio requirement as of the end of each fiscal quarter to certain ratios above the 4.50 to 1.00 ratio otherwise in effect after giving effect to the Fourth Amendment, subject to compliance with certain restrictions on restricted payments and permitted acquisitions during such covenant relief period. Furthermore, after giving effect to the Fourth Amendment and whether or not the covenant relief period is in effect, (i) if the Borrower’s consolidated total net leverage ratio is equal to or greater than 4.00 to 1.00 but less than 4.50 to 1.00, the interest rate on all outstanding borrowings of revolving credit loans under the Credit Agreement will step-up to the LIBOR plus 2.25% or a base rate plus 1.25% and the commitment fee will step-up to 0.375% and (ii) if Predecessor US Ecology’s consolidated total net leverage ratio is greater than 4.50 to 1.00, the interest rate on all outstanding borrowings of revolving credit loans under the Credit Agreement will step-up to LIBOR plus 2.50% or a base rate plus 1.50% and the commitment fee will step-up to 0.40%, in each case, pursuant to the terms of the Credit Agreement. The Fourth Amendment also reset any outstanding usage of certain negative covenant baskets, including baskets in connection with the indebtedness, liens, investments, asset dispositions, restricted payments and affiliate transactions negative covenants. ​ 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). As modified by the Fourth Amendment, under the Revolving Credit Facility, revolving credit loans are available based on a base rate (as defined in the Credit Agreement) or 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 EBITDA (as defined in the Credit Agreement), as set forth in the table below: ​ ​ ​ ​ Consolidated Total Net Leverage Ratio LIBOR Rate Loans Interest Margin Base Rate Loans Interest Margin Equal to or greater than 4.50 to 1.00 2.50% 1.50% Equal to or greater than 4.00 to 1.00, but less than 4.50 to 1.00 2.25% 1.25% Equal to or greater than 3.25 to 1.00, but less than 4.00 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, 2022, 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 3.94%. Interest only payments are due either quarterly or on the last day of any interest period, as applicable. ​ As modified by the Fourth Amendment, Predecessor US Ecology is required to pay a commitment fee ranging from 0.175% to 0.40% on the average daily unused portion of the Revolving Credit Facility, with such commitment fee to be based upon Predecessor US Ecology’s total net leverage ratio (as defined in the Credit Agreement). At March 31, 2022, there were $303.0 million of revolving credit loans outstanding on the Revolving Credit Facility, which 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, 2022, there were no borrowings outstanding subject to the Sweep Arrangement. ​ As of March 31, 2022, the availability under the Revolving Credit Facility was $27.7 million, subject to our leverage covenant limitation, with $12.2 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 Outstandings exceed 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. ​ 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 as financial maintenance covenants a maximum consolidated total net leverage ratio and a consolidated interest coverage ratio. Except as further modified by the Third Amendment and Fourth Amendment as described above, our consolidated total net leverage ratio as of the last day of each fiscal quarter may not exceed 4.50:1:00. Our consolidated interest coverage ratio as of the last day of any fiscal quarter may not be less than 3.00 to 1.00. At March 31, 2022, we were in compliance with all of the financial covenants in the Credit Agreement. It is currently expected that all outstanding borrowings under the Credit Agreement will be repaid and the Credit Agreement will be terminated in connection with the consummation of the Merger. ​ Interest Rate Swap ​ In March 2020, the Company entered into an interest rate swap agreement with Wells Fargo, effectively fixing the interest rate on $430.0 million, or approximately 58%, of the Revolving Credit Facility and term loan borrowings outstanding as of March 31, 2022. 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) remained probable, the $1.8 million net loss related to the terminated swap reported in AOCI at the termination date was amortized as additional interest expense over its original maturity.

CLOSURE AND POST-CLOSURE OBLIGA

CLOSURE AND POST-CLOSURE OBLIGATIONS	3 Months Ended
	Mar. 31, 2022
CLOSURE AND POST-CLOSURE OBLIGATIONS
CLOSURE AND POST-CLOSURE OBLIGATIONS	NOTE 11. CLOSURE AND POST-CLOSURE OBLIGATIONS ​ Our accrued closure and post-closure liability represent 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, 2022 Closure and post-closure obligations, beginning of period ​ $ 98,920 Accretion expense ​ 1,227 Payments ​ (517) Foreign currency translation ​ 24 Closure and post-closure obligations, end of period ​ 99,654 Less current portion ​ (6,322) Long-term portion ​ $ 93,332 ​

INCOME TAXES

INCOME TAXES	3 Months Ended
	Mar. 31, 2022
INCOME TAXES
INCOME TAXES	NOTE 12. INCOME TAXES ​ We have historically calculated the provision for income taxes during interim reporting periods by applying an estimate of the Annual Effective Tax Rate (“AETR”) for the full fiscal year to “ordinary” income or loss (pretax income or loss excluding unusual or infrequently occurring discrete items) for the reporting period. We used a discrete effective tax rate method to calculate taxes for the three months ended March 31, 2022. We determined that since relatively small changes in estimated “ordinary” income would result in significant changes in the estimated AETR, that the historical method would not provide a reliable estimate for the three months ended March 31, 2022. ​ Income tax benefit for the three months ended March 31, 2022 was $2.0 million, resulting in an effective tax rate of 18.2%. Income tax benefit for the three months ended March 31, 2021 was $1.4 million resulting in an effective tax rate of 64.5%. The decrease in our effective tax rate for the three months ended March 31, 2022 compared to the three months ended March 31, 2021 was primarily due to non-deductible business development costs for the three months ended March 31, 2022, partially offset by a reduction in our state income taxes due to legislation enacted during the three months ended March 31, 2022. ​ Gross unrecognized tax benefits, included in Other long-term liabilities in the consolidated balance sheets, were $269,000 and $256,000 as of March 31, 2022 and December 31, 2021, respectively. The gross unrecognized tax benefits, if recognized by the Company, will result in a reduction of approximately $269,000 to the provision for income taxes. 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 in Interest expense and Selling, general and administrative expenses, respectively. The total accrued interest related to unrecognized tax benefits as of March 31, 2022 and December 31, 2021 were not significant. There is no accrual for penalties. ​ The Company files income tax returns in the U.S. Federal and various state, local and foreign jurisdictions. The Company is subject to examination by the Internal Revenue Service for tax years beginning in 2018. The 2017 through 2021 state tax returns are subject to examination by state tax authorities. Stablex Canada, Inc. is currently under examination by the Canadian Revenue Agency for years 2018 through 2020. The tax years 2017 through 2021 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. ​ ​

LOSS PER SHARE

LOSS PER SHARE	3 Months Ended
	Mar. 31, 2022
LOSS PER SHARE
LOSS PER SHARE	NOTE 13. LOSS PER SHARE ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, ​ ​ 2022 ​ 2021 $s and shares in thousands, except per share amounts Basic Diluted Basic Diluted Net loss ​ $ (9,022) ​ $ (9,022) ​ $ (796) ​ $ (796) Weighted average basic shares outstanding ​ 31,208 ​ 31,208 ​ 31,104 ​ 31,104 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Dilutive effect of share-based awards and warrants ​ ​ ​ ​ — ​ ​ ​ ​ — Weighted average diluted shares outstanding ​ ​ ​ ​ 31,208 ​ ​ ​ ​ 31,104 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Loss per share ​ $ (0.29) ​ $ (0.29) ​ $ (0.03) ​ $ (0.03) Anti-dilutive shares excluded from calculation ​ ​ ​ ​ 4,207 ​ ​ ​ ​ 4,369 ​

EQUITY

EQUITY	3 Months Ended
	Mar. 31, 2022
EQUITY
EQUITY	NOTE 14. EQUITY ​ Stock Repurchase Program ​ On June 6, 2020, the Company’s Board of Directors’ authorization to repurchase the Company’s outstanding shares of common stock and warrants under the share repurchase program expired. In the future, the Board of Directors may consider reauthorizing the repurchase program at any time, and the timing of any future 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. ​ Omnibus Incentive Plan ​ On May 27, 2015, the stockholders of Predecessor US Ecology approved the Omnibus Incentive Plan (as amended, “Pre-Merger 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 Pre-Merger Omnibus Plan, amended and restated such plan and renamed it the Amended and Restated US Ecology, Inc. Omnibus Incentive Plan (the “Omnibus Plan”) for the purpose of issuing replacement awards to award recipients under the Omnibus Plan pursuant to the NRC 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, consultants and non-employee 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 employees, consultants and non-employee directors. The Omnibus Plan expires on March 31, 2031 and authorizes 3,272,000 shares of common stock for grant over the life of the Omnibus Plan. As of March 31, 2022, 1,885,810 shares of common stock remain available for grant under the Omnibus Plan. Subsequent to the approval of the Pre-Merger Omnibus Plan by Predecessor US Ecology in May 2015, we stopped granting equity awards under the American Ecology Corporation 2008 Stock Option Incentive Plan (“Pre-Merger 2008 Stock Option Plan”). However, in connection with the closing of the NRC Merger, the Company assumed the Pre-Merger 2008 Stock Option Plan, amended and restated such plan and renamed it in the Amended and Restated US Ecology, Inc. 2008 Stock Option Incentive Plan (the “2008 Stock Option Plan”) solely for the purpose of issuing replacement awards to award recipients thereunder and remains in effect solely for the settlement of awards granted under such plan and no future grants may be made 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 solely for the purpose of issuing replacement awards to award recipients thereunder pursuant to the NRC Merger Agreement, and no future grants may be made under such plan. ​ Performance Stock Units (“PSUs”), Restricted Stock and Restricted Stock Units (“RSUs”) ​ On January 3, 2022, the Company granted 62,178 PSUs to certain employees. Each PSU represents the right to receive, on the settlement date, one share of the Company’s common stock. The total number of PSUs each participant is eligible to earn ranges from 0% to 250% of the target number of PSUs granted. The actual number of PSUs that will vest and be settled in shares is determined based on achievement of certain Company financial performance metrics over a one-year performance period beginning January 1, 2022, further adjusted based on total shareholder return relative to a set of peer companies at the end of a three-year performance period beginning January 1, 2022. The fair value of the PSUs estimated on the grant date using a Monte Carlo simulation was $34.65 per unit. Compensation expense is recorded over the awards’ vesting period. ​ Assumptions used in the Monte Carlo simulation to calculate the fair value of the PSUs granted on January 3, 2022 are as follows: ​ ​ ​ ​ ​ ​ ​ 2022 Stock price on grant date ​ $ 31.86 ​ Expected term ​ 3.0 years Expected volatility ​ ​ 40.1 % Risk-free interest rate ​ 1.0 % ​ ​ A summary of our PSU, restricted stock and RSU activity for the three months ended March 31, 2022 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, 2021 53,385 ​ $ 42.79 110,564 ​ $ 41.85 ​ 126,549 ​ $ 36.78 Granted 62,178 ​ ​ 34.65 62,178 ​ ​ 31.86 ​ 81,495 ​ ​ 31.86 Vested (589) ​ ​ 54.55 (35,935) ​ 46.65 ​ (57,840) ​ 37.90 Cancelled, expired or forfeited — ​ ​ — — ​ — ​ (2,655) ​ 34.30 Outstanding as of March 31, 2022 114,974 ​ $ 38.33 136,807 ​ $ 36.05 ​ 147,549 ​ $ 33.67 ​ During the three months ended March 31, 2022, 589 PSUs vested and PSU holders earned 589 shares of the Company’s common stock. ​ Stock Options ​ A summary of our stock option activity for the three months ended March 31, 2022 is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ Average ​ ​ ​ ​ Exercise ​ Shares Price Outstanding as of December 31, 2021 546,594 ​ $ 44.59 Outstanding as of March 31, 2022 546,594 ​ $ 44.59 Exercisable as of March 31, 2022 386,763 ​ $ 47.16 ​ Treasury Stock ​ During the three months ended March 31, 2022, the Company repurchased 379 shares of the Company’s common stock in connection with the net share settlement of employee withholding taxes due on vested equity awards at an average cost of $31.89 per share and issued 102,193 shares of common stock from our treasury stock in connection with employee equity awards at an average cost of $43.91 per share ​ Warrants ​ At March 31, 2022, there were a total of 3,772,753 warrants outstanding. Each warrant entitles the holder thereof to purchase one share of common stock at a price of $58.67 per share, subject to certain adjustments. The warrants may be exercised only for a whole number of shares of common stock. No fractional shares will be issued upon exercise of the warrants. The warrants will expire at 5:00 p.m. New York City time on October 17, 2023, or earlier upon redemption or liquidation. The warrants are listed on the Nasdaq Capital Market under the symbol “ECOLW”. The Company may call the warrants for redemption, in whole and not in part, at a price of $0.01 per warrant, upon not less than 30 days’ prior written notice of redemption to each warrant holder, if, and only if, the reported last sale price of common stock equals or exceeds $91.84 per share on each of 20 trading days within the 30 trading-day period ending on the business day prior to the date on which notice of the redemption is given and provided that there is an effective registration statement covering the shares of common stock issuable on exercise of the warrants and subject to the satisfaction of certain other requirements. The warrants were determined to be equity classified in accordance with ASC 815, Derivatives and Hedging Distinguishing Liabilities from Equity ​ Dividends ​ The Company did not pay any dividends during the three months ended March 31, 2022 or the three months ended March 31, 2021.

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	3 Months Ended
	Mar. 31, 2022
COMMITMENTS AND CONTINGENCIES
COMMITMENTS AND CONTINGENCIES	NOTE 15. 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 out of or related to BP’s indemnity claims, such liability would be covered by an indemnity by SEACOR Holdings Inc., the former owner of National Response Corporation, in favor of National Response Corporation and its affiliates. On November 17, 2018, an explosion occurred at our Grand View, Idaho facility. 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 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. In November 2020, we commenced a lawsuit against the generator and broker of the waste, the treatment of which we believe contributed to the Grand View explosion, seeking damages in connection with the losses suffered as a result of the incident. 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 September 2021, Robert Dell, a Marine Technician for NRC from June 2021 to September 2021, filed a class action complaint against US Ecology in the Alameda Superior Court for the State of California (Robert Dell et. al. v. US Ecology Illinois, Inc., US Ecology, Inc., and US Ecology Vernon, Inc.) alleging the failure by the defendants to pay wages and/or overtime, failure to provide accurate itemized wage statements, and failure to provide meal and rest breaks as required by California law. Further, Mr. Dell has put the Labor & Workforce Development Agency on notice in an effort to exhaust administrative remedies and enable him to bring an additional claim under the California Labor Code Private Attorneys General Act, which permits an employee to assert a claim for violations of certain California Labor Code provisions on behalf of all aggrieved employees to recover statutory penalties. Given the recency of the filing, the Company has not yet filed a response to Mr. Dell’s complaint. The Company believes that Mr. Dell’s claims lack merit and intends to vigorously defend this action. The Company is currently unable to estimate the range of possible losses associated with this proceeding. ​ Commencing on March 15, 2022, purported individual stockholders of US Ecology filed complaints in the United States District Courts for the Southern District of New York, for the Eastern District of New York, and for the Eastern District of Pennsylvania, in the matters captioned Ryan O’Dell v. US Ecology, Inc., et al, No. 22-cv-2131 (S.D.N.Y., filed Mar. 15, 2022) (“O’Dell”), Ray Pizzaro v. US Ecology, Inc., et al, No. 22-cv-02144 (S.D.N.Y., filed Mar. 15, 2022) (“Pizzaro”), Matthew Whitfield v. US Ecology, Inc., et al, No. 22-cv-01515 (E.D.N.Y., filed Mar. 18, 2022) (“Whitfield”), Lewis D. Baker v. US Ecology, Inc., et al, No. 22-cv-01053 (E.D. Pa., filed Mar. 18, 2022) (“Baker”), and Teresa McCurdy v. US Ecology, Inc. et al, No. 22-cv-01685 (E.D.N.Y., filed Mar. 25, 2022) (“McCurdy,” and together, the “Transaction Litigation”). The complaints in the Transaction Litigation named as defendants the Company and the members of the Board. In addition to the Transaction Litigation, the Company received letters from four purported stockholders of the Company demanding additional disclosures related to the sale process leading to the proposed transaction, the Company's financial projections and the analyses performed by the Co-Financial Advisors. ​ The complaints in the Transaction Litigation generally alleged that the preliminary proxy statement filed by US Ecology with the SEC on March 11, 2022, in connection with the Merger Agreement was materially incomplete and misleading by allegedly failing to disclose purportedly material information relating to the sale process leading to the proposed transaction, the Company’s financial projections, and the analyses performed by Barclays Capital, Inc. and Houlihan Lokey Capital, Inc. (collectively, the “Co-Financial Advisors”). Each of the Complaints asserted violations of Section 14(a) of the Exchange Act, Rule 14a-9 promulgated thereunder, and Section 20(a) of the Exchange Act. In addition, the complaint in the Pizzaro action also asserted a claim for breach of fiduciary duty by the members of the Board in connection with the approval of the Merger Agreement and the disclosures in the preliminary proxy statement, and a claim against US Ecology for aiding and abetting the alleged breaches of fiduciary duty. The Transaction Litigation sought, among other things, an injunction of the proposed transaction, rescission of the Merger Agreement, a declaratory judgment that the Company and the Board violated the Exchange Act and Rule 14a-9 promulgated thereunder, damages, plaintiff’s attorneys’ fees and expenses, and any other relief the court may deem just and proper. As of April 25, 2022, plaintiffs in each of the Transaction Litigation matters filed voluntary dismissals of their complaints. ​ It is possible that additional similar complaints could be filed in connection with the proposed transaction. If additional similar complaints are filed, absent new or significantly different allegations, US Ecology will not necessarily disclose such additional complaints or filings ​ Other than as described herein, as of March 31, 2022, we were not a party to any material pending legal proceedings and are not aware of any other claims that could, individually or in the aggregate, have a materially adverse effect on our financial position, results of operations or cash flows. The decision to accrue costs or write-off assets is based on the pertinent facts and our evaluation of present circumstances.

OPERATING SEGMENTS

OPERATING SEGMENTS	3 Months Ended
	Mar. 31, 2022
OPERATING SEGMENTS
OPERATING SEGMENTS	NOTE 16. OPERATING SEGMENTS ​ Financial Information by Segment ​ Our operations are managed in three reportable segments reflecting our internal management reporting structure and nature of services offered as follows: ​ Waste Solutions (formerly “Environmental Services”) ​ Field Services (formerly “Field & Industrial Services”) ​ Energy Waste ​ The operations not managed through our three reportable segments are recorded as “Corporate.” Corporate selling, general and administrative expenses include typical corporate items of a general nature such as certain labor, information technology, legal, accounting and other expenses not associated with a specific reportable segment. 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, 2022 ​ ​ Waste ​ Field ​ Energy ​ ​ ​ ​ ​ ​ $s in thousands Solutions Services Waste Corporate Total Revenue ​ $ 114,766 ​ $ 112,323 ​ $ 13,891 ​ $ — ​ $ 240,980 Depreciation, amortization and accretion ​ $ 10,154 ​ $ 10,592 ​ $ 4,434 ​ $ 819 ​ $ 25,999 Capital expenditures ​ $ 11,274 ​ $ 3,480 ​ $ 581 ​ $ 845 ​ $ 16,180 Total assets ​ $ 808,976 ​ $ 725,894 ​ $ 215,495 ​ $ 68,308 ​ $ 1,818,673 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, 2021 ​ ​ Waste ​ Field ​ Energy ​ ​ ​ ​ ​ ​ $s in thousands Solutions Services Waste Corporate Total Revenue ​ $ 104,142 ​ $ 118,249 ​ $ 6,228 ​ $ — ​ $ 228,619 Depreciation, amortization and accretion ​ $ 11,431 ​ $ 11,371 ​ $ 4,965 ​ $ 784 ​ $ 28,551 Capital expenditures ​ $ 8,145 ​ $ 931 ​ $ 283 ​ $ 255 ​ $ 9,614 Total assets ​ $ 789,277 ​ $ 753,209 ​ $ 228,689 ​ $ 51,977 ​ $ 1,823,152 ​ 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 loss before interest expense, interest income, income tax expense/benefit, depreciation, amortization, share-based compensation, accretion of closure and post-closure liabilities, foreign currency gain/loss, business development and integration expenses and other income/expense. 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 loss to Adjusted EBITDA is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, $s in thousands 2022 2021 Net loss ​ $ (9,022) ​ $ (796) Income tax benefit ​ ​ (2,014) ​ ​ (1,444) Interest expense ​ ​ 6,821 ​ ​ 7,357 Interest income ​ ​ (229) ​ ​ (273) Foreign currency loss ​ ​ 698 ​ ​ 371 Other income ​ ​ (177) ​ ​ (3,710) Depreciation and amortization of plant and equipment ​ ​ 16,900 ​ ​ 18,234 Amortization of intangible assets ​ ​ 7,872 ​ ​ 9,135 Share-based compensation ​ ​ 1,948 ​ ​ 1,928 Accretion and non-cash adjustment of closure & post-closure liabilities ​ ​ 1,227 ​ ​ 1,182 Business development and integration expenses ​ ​ 5,859 ​ ​ 1,220 Adjusted EBITDA ​ $ 29,883 ​ $ 33,204 ​ Adjusted EBITDA, by operating segment, is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, $s in thousands ​ 2022 2021 Waste Solutions $ 41,418 ​ $ 40,136 Field Services 10,922 ​ 17,137 Energy Waste ​ ​ 4,725 ​ ​ 1,258 Corporate (27,182) ​ (25,327) Total $ 29,883 ​ $ 33,204 ​ 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 ​ 2022 2021 United States ​ $ 846,701 ​ $ 855,200 Canada ​ 66,360 ​ 65,437 EMEA ​ ​ 14,802 ​ ​ 15,604 Other (1) ​ ​ 9,305 ​ ​ 9,716 Total long-lived assets, net ​ $ 937,168 ​ $ 945,957 (1) Includes Mexico, Asia Pacific, and Latin America and Caribbean geographical regions.

GENERAL (Policies)

GENERAL (Policies)	3 Months Ended
	Mar. 31, 2022
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, 2021. The results of operations for the three months ended March 31, 2022 are not necessarily indicative of the results to be expected for the entire year ending December 31, 2022. ​ The Company’s consolidated balance sheet as of December 31, 2021 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 March 2020, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2020-04, “Facilitation of the Effects of Reference Rate Reform on Financial Reporting” (Topic 848). The ASU provides optional expedients and exceptions for applying GAAP to transactions affected by reference rate (e.g., LIBOR) reform if certain criteria are met, for a limited period of time to ease the potential burden in accounting for (or recognizing the effects of) reference rate reform on financial reporting. The ASU is effective as of March 12, 2020 through December 31, 2022. We will evaluate transactions or contract modifications occurring as a result of reference rate reform and determine whether to apply the optional guidance on an ongoing basis. The ASU is currently not expected to have a material impact on our consolidated financial statements.
Republic Services, Inc. Merger Agreement	Republic Services, Inc. Merger Agreement On February 8, 2022, we entered into the previously disclosed Agreement and Plan of Merger (the “Merger Agreement”) with Republic Services, Inc., a Delaware corporation (“Republic”) and Bronco Acquisition Corp., a Delaware corporation and a wholly-owned subsidiary of Republic (“Merger Sub”). The Merger Agreement provides that, upon the terms and subject to the conditions set forth in the Merger Agreement, Merger Sub will merge with and into the Company (the “Merger”), with the Company continuing as the surviving corporation and as a wholly-owned subsidiary of Republic. The foregoing description of the Merger Agreement is a summary only and is qualified in its entirety by reference to the complete text of the Merger Agreement filed as Exhibit 2.1 in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2021. On March 30, 2022 the waiting period under Hart Scott-Rodino Anitrust Improvements Act of 1976, as amended, expired with respect to the Merger, and on April 26, 2022 we held a Special Meeting of the stockholders of the Company wherein we received the necessary affirmative vote to consummate the Merger. The transaction is currently expected to close on May 2, 2022.

REVENUES (Tables)

REVENUES (Tables)	3 Months Ended
	Mar. 31, 2022
REVENUES
Schedule of disaggregation of revenues	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, 2022 ​ ​ Waste ​ Field ​ Energy ​ ​ ​ $s in thousands Solutions Services ​ Waste Total Treatment & Disposal Revenue (1) ​ $ 96,280 ​ $ 10,781 ​ $ 7,104 ​ $ 114,165 Services Revenue: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Transportation and Logistics (2) ​ ​ 18,486 ​ ​ 7,273 ​ ​ 4,384 ​ ​ 30,143 Industrial Services (3) ​ ​ — ​ ​ 28,870 ​ ​ 972 ​ ​ 29,842 Small Quantity Generation (4) ​ ​ — ​ ​ 15,039 ​ ​ — ​ ​ 15,039 Total Waste Management (5) ​ ​ — ​ ​ 10,589 ​ ​ — ​ ​ 10,589 Remediation (6) ​ ​ — ​ ​ 5,360 ​ ​ — ​ ​ 5,360 Emergency Response (7) ​ ​ — ​ ​ 31,416 ​ ​ — ​ ​ 31,416 Other (8) ​ ​ — ​ ​ 2,995 ​ ​ 1,431 ​ ​ 4,426 Revenue ​ $ 114,766 ​ $ 112,323 ​ $ 13,891 ​ $ 240,980 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, 2021 ​ ​ Waste ​ Field ​ Energy ​ ​ ​ $s in thousands Solutions Services ​ Waste Total Treatment & Disposal Revenue (1) ​ $ 88,060 ​ $ 9,977 ​ $ 3,783 ​ $ 101,820 Services Revenue: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Transportation and Logistics (2) ​ ​ 16,082 ​ ​ 6,329 ​ ​ 1,401 ​ ​ 23,812 Industrial Services (3) ​ ​ — ​ ​ 26,256 ​ ​ 409 ​ ​ 26,665 Small Quantity Generation (4) ​ ​ — ​ ​ 13,052 ​ ​ — ​ ​ 13,052 Total Waste Management (5) ​ ​ — ​ ​ 9,882 ​ ​ — ​ ​ 9,882 Remediation (6) ​ ​ — ​ ​ 11,975 ​ ​ — ​ ​ 11,975 Emergency Response (7) ​ ​ — ​ ​ 37,355 ​ ​ — ​ ​ 37,355 Other (8) ​ ​ — ​ ​ 3,423 ​ ​ 635 ​ ​ 4,058 Revenue ​ $ 104,142 ​ $ 118,249 ​ $ 6,228 ​ $ 228,619 (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, 2022 and 2021, 20% and 24% , respectively, of our treatment and disposal revenue was derived from Event Business projects. Base Business revenue accounted for 80% and 76% of our treatment and disposal revenue for the three months ended March 31, 2022 and 2021, 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 services such as spill response, waste analysis and treatment and disposal planning as well as government-mandated, commercial standby oil spill compliance solutions and services that we provide 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. (8) Includes equipment rental and other miscellaneous services. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, 2022 ​ Three Months Ended March 31, 2021 ​ ​ Waste ​ Field ​ Energy ​ ​ ​ ​ Waste ​ Field ​ Energy ​ ​ ​ $s in thousands Solutions Services Waste Total Solutions Services Waste Total United States ​ $ 97,142 ​ $ 104,440 ​ $ 13,891 ​ $ 215,473 ​ $ 84,474 ​ $ 106,051 ​ $ 6,228 ​ $ 196,753 Canada ​ ​ 17,624 ​ ​ 592 ​ ​ — ​ ​ 18,216 ​ ​ 19,668 ​ ​ 579 ​ ​ — ​ ​ 20,247 EMEA ​ ​ — ​ ​ 6,264 ​ ​ — ​ ​ 6,264 ​ ​ — ​ ​ 10,018 ​ ​ — ​ ​ 10,018 Other (1) ​ — ​ 1,027 ​ — ​ 1,027 ​ — ​ 1,601 ​ — ​ 1,601 Total revenue ​ $ 114,766 ​ $ 112,323 ​ $ 13,891 ​ $ 240,980 ​ $ 104,142 ​ $ 118,249 ​ $ 6,228 ​ $ 228,619 (1) Includes Mexico, Asia Pacific, and Latin America and Caribbean geographical regions. ​

ACCUMULATED OTHER COMPREHENSI_2

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Tables)	3 Months Ended
	Mar. 31, 2022
ACCUMULATED OTHER COMPREHENSIVE 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, 2021 ​ $ (9,375) ​ $ 5,181 ​ $ (4,194) Other comprehensive income before reclassifications, net of tax ​ 1,469 ​ 12,746 ​ 14,215 Amounts reclassified out of AOCI, net of tax (1) ​ — ​ 508 ​ 508 Other comprehensive income, net ​ 1,469 ​ 13,254 ​ 14,723 Balance at March 31, 2022 ​ $ (7,906) ​ $ 18,435 ​ $ 10,529 (1) Before-tax reclassifications of $642,000 ($508,000 after-tax) for the three months ended March 31, 2022, 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 $1.2 million ($927,000 after-tax). ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Foreign ​ Unrealized Gain ​ ​ ​ ​ ​ Currency ​ (Loss) on Interest ​ ​ ​ $s in thousands Translation Rate Hedge Total Balance at December 31, 2020 ​ $ (7,870) ​ $ (6,788) ​ $ (14,658) Other comprehensive income before reclassifications, net of tax ​ 1,439 ​ 8,323 ​ 9,762 Amounts reclassified out of AOCI, net of tax (2) ​ — ​ 894 ​ 894 Other comprehensive income, net ​ 1,439 ​ 9,217 ​ 10,656 Balance at March 31, 2021 ​ $ (6,431) ​ $ 2,429 ​ $ (4,002) (2) Before-tax reclassifications of $1.1 million ($894,000 after-tax) for the three months ended March 31, 2021, 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.

RECEIVABLES (Tables)

RECEIVABLES (Tables)	3 Months Ended
	Mar. 31, 2022
RECEIVABLES
Schedule of receivables	​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, ​ December 31, $s in thousands ​ 2022 2021 Trade ​ $ 186,906 ​ $ 183,747 Unbilled revenue ​ 60,513 ​ 62,029 Other ​ 3,834 ​ 7,421 Total receivables ​ 251,253 ​ 253,197 Allowance for credit losses ​ (3,020) ​ (3,043) Receivables, net ​ $ 248,233 ​ $ 250,154

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	3 Months Ended
	Mar. 31, 2022
FAIR VALUE MEASUREMENTS
Schedule of assets and liabilities measured at fair value on a recurring basis	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, 2022 ​ ​ Quoted Prices in ​ Other Observable ​ Unobservable ​ ​ ​ ​ ​ Active Markets ​ Inputs ​ Inputs ​ ​ ​ $s in thousands (Level 1) (Level 2) (Level 3) Total Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Money market funds (2) ​ ​ 1,597 ​ ​ — ​ ​ — ​ ​ 1,597 Interest rate swap agreement (3) ​ ​ — ​ ​ 21,900 ​ ​ — ​ ​ 21,900 Total ​ $ 1,597 ​ $ 21,900 ​ $ — ​ $ 23,497 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2021 ​ ​ 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) ​ $ 1,695 ​ $ 255 ​ $ — ​ $ 1,950 Money market funds (2) ​ ​ 1,886 ​ ​ — ​ ​ — ​ ​ 1,886 Interest rate swap agreement (3) ​ ​ — ​ ​ 5,022 ​ ​ — ​ ​ 5,022 Total ​ $ 3,581 ​ $ 5,277 ​ $ — ​ $ 8,858 (1) We had short-term investments in fixed-income securities, including U.S. Treasury and U.S. agency securities as of December 31, 2021. We measured the fair value of U.S. Treasury securities using quoted prices for identical assets in active markets. We measured the fair value of U.S. agency securities using observable market activity for similar assets. The fair value of our fixed-income securities approximated 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-year and end-of-year 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 assets in the Company’s consolidated balance sheets as of March 31, 2022 and December 31, 2021, respectively.

PROPERTY AND EQUIPMENT (Tables)

PROPERTY AND EQUIPMENT (Tables)	3 Months Ended
	Mar. 31, 2022
PROPERTY AND EQUIPMENT
Schedule of property and equipment	​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, ​ December 31, $s in thousands ​ 2022 2021 Cell development costs ​ $ 204,067 ​ $ 203,217 Land and improvements ​ 74,524 ​ 74,298 Buildings and improvements ​ 137,204 ​ 138,659 Railcars ​ 17,299 ​ 17,299 Vehicles, vessels and other equipment ​ 352,925 ​ 350,950 Construction in progress ​ 65,798 ​ 54,609 Total property and equipment ​ 851,817 ​ 839,032 Accumulated depreciation and amortization ​ (396,776) ​ (382,648) Property and equipment, net ​ $ 455,041 ​ $ 456,384

LEASES (Tables)

LEASES (Tables)	3 Months Ended
	Mar. 31, 2022
LEASES
Summary of leased assets and liabilities	​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, ​ December 31, $s in thousands 2022 2021 Assets: ​ ​ ​ ​ ​ ​ Operating right-of-use assets (1) ​ $ 54,884 ​ $ 43,607 Finance right-of-use assets (2) ​ ​ 15,788 ​ ​ 17,290 Total ​ $ 70,672 ​ $ 60,897 ​ ​ ​ ​ ​ ​ ​ Liabilities: ​ ​ ​ ​ ​ ​ Current: ​ ​ ​ ​ ​ ​ Operating (3) ​ $ 17,780 ​ $ 15,799 Finance (4) ​ ​ 4,778 ​ ​ 4,969 Long-term: ​ ​ ​ ​ ​ ​ Operating (5) ​ ​ 37,991 ​ ​ 28,477 Finance (6) ​ ​ 11,119 ​ ​ 12,108 Total ​ $ 71,668 ​ $ 61,353 (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 $14.6 million and $13.3 million as of March 31, 2022 and December 31, 2021, 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 2022 2021 Operating lease cost (1) ​ $ 5,123 ​ $ 5,296 Finance lease cost: ​ ​ ​ ​ ​ ​ Amortization of leased assets (2) ​ ​ 1,295 ​ ​ 1,334 Interest on lease liabilities (3) ​ ​ 265 ​ ​ 278 Total ​ $ 6,683 ​ $ 6,908 (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 2022 2021 Cash paid for amounts included in the measurement of lease liabilities: ​ ​ ​ ​ ​ ​ Operating cash flows from operating leases ​ $ 4,905 ​ $ 5,151 Operating cash flows from finance leases ​ $ 265 ​ $ 278 Financing cash flows from finance leases ​ $ 1,180 ​ $ 1,192 ​ ​ ​ ​ ​ ​ ​ Non-cash investing and financing activities: ​ ​ ​ ​ ​ ​ Right-of-use assets obtained in exchange for new operating lease liabilities ​ $ 16,054 ​ $ 2,074

GOODWILL AND INTANGIBLE ASSETS

GOODWILL AND INTANGIBLE ASSETS (Tables)	3 Months Ended
	Mar. 31, 2022
GOODWILL AND INTANGIBLE ASSETS
Schedule of changes in goodwill	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Waste Solutions ​ Field Services ​ Energy Waste ​ ​ ​ ​ ​ ​ ​ Accumulated ​ ​ ​ Accumulated ​ ​ ​ Accumulated ​ ​ ​ $s in thousands Gross Impairment Gross Impairment Gross Impairment Total Balance at December 31, 2021 ​ $ 166,925 ​ $ (6,870) ​ $ 237,368 ​ $ (19,900) ​ $ 399,503 ​ $ (363,900) ​ $ 413,126 Foreign currency translation ​ 278 ​ ​ — ​ 122 ​ ​ — ​ ​ — ​ ​ — ​ 400 Balance at March 31, 2022 ​ $ 167,203 ​ $ (6,870) ​ $ 237,490 ​ $ (19,900) ​ $ 399,503 ​ $ (363,900) ​ $ 413,526
Schedule of intangible assets, net	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, 2022 ​ December 31, 2021 ​ ​ ​ ​ ​ Accumulated ​ ​ ​ ​ ​ ​ ​ Accumulated ​ ​ ​ $s in thousands Cost Amortization Net Cost Amortization Net Amortizing intangible assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Permits, licenses and lease ​ $ 175,299 ​ $ (28,331) ​ $ 146,968 ​ $ 174,959 ​ $ (27,170) ​ $ 147,789 Customer relationships ​ ​ 340,215 ​ ​ (94,542) ​ ​ 245,673 ​ ​ 340,065 ​ ​ (87,952) ​ ​ 252,113 Technology - formulae and processes ​ 7,277 ​ (2,628) ​ 4,649 ​ 7,166 ​ (2,531) ​ 4,635 Customer backlog ​ 3,652 ​ (2,843) ​ 809 ​ 3,652 ​ (2,752) ​ 900 Tradename ​ 10,390 ​ ​ (10,390) ​ ​ — ​ 10,390 ​ ​ (10,390) ​ ​ — Developed software ​ ​ 2,907 ​ ​ (2,552) ​ ​ 355 ​ ​ 2,903 ​ ​ (2,475) ​ ​ 428 Non-compete agreements ​ 5,583 ​ (5,256) ​ 327 ​ 5,573 ​ (5,211) ​ 362 Internet domain and website ​ ​ 536 ​ ​ (220) ​ ​ 316 ​ ​ 536 ​ ​ (213) ​ ​ 323 Database ​ ​ 391 ​ ​ (241) ​ ​ 150 ​ ​ 390 ​ ​ (235) ​ ​ 155 Total amortizing intangible assets ​ 546,250 ​ (147,003) ​ 399,247 ​ 545,634 ​ (138,929) ​ 406,705 Non-amortizing intangible assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Permits and licenses ​ 82,744 ​ ​ — ​ 82,744 ​ 82,734 ​ ​ — ​ 82,734 Tradename ​ 136 ​ ​ — ​ ​ 136 ​ 134 ​ ​ — ​ ​ 134 Total intangible assets ​ $ 629,130 ​ $ (147,003) ​ $ 482,127 ​ $ 628,502 ​ $ (138,929) ​ $ 489,573

DEBT (Tables)

DEBT (Tables)	3 Months Ended
	Mar. 31, 2022
DEBT
Schedule of long-term debt	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, ​ December 31, $s in thousands 2022 2021 Revolving credit facility ​ $ 303,000 ​ $ 303,000 Term loan ​ ​ 439,875 ​ ​ 441,000 Unamortized term loan discount and debt issuance costs ​ ​ (5,231) ​ ​ (5,516) Total debt ​ ​ 737,644 ​ ​ 738,484 Current portion of long-term debt ​ ​ (3,359) ​ ​ (3,359) Long-term debt ​ $ 734,285 ​ $ 735,125
Schedule of interest margins based on the total net leverage ratio	​ ​ ​ ​ Consolidated Total Net Leverage Ratio LIBOR Rate Loans Interest Margin Base Rate Loans Interest Margin Equal to or greater than 4.50 to 1.00 2.50% 1.50% Equal to or greater than 4.00 to 1.00, but less than 4.50 to 1.00 2.25% 1.25% Equal to or greater than 3.25 to 1.00, but less than 4.00 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, 2022
CLOSURE AND POST-CLOSURE OBLIGATIONS
Schedule of changes to reported closure and post closure obligations	​ ​ ​ ​ ​ ​ ​ Three Months Ended $s in thousands March 31, 2022 Closure and post-closure obligations, beginning of period ​ $ 98,920 Accretion expense ​ 1,227 Payments ​ (517) Foreign currency translation ​ 24 Closure and post-closure obligations, end of period ​ 99,654 Less current portion ​ (6,322) Long-term portion ​ $ 93,332

LOSS PER SHARE (Tables)

LOSS PER SHARE (Tables)	3 Months Ended
	Mar. 31, 2022
LOSS PER SHARE
Schedule of loss per share	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, ​ ​ 2022 ​ 2021 $s and shares in thousands, except per share amounts Basic Diluted Basic Diluted Net loss ​ $ (9,022) ​ $ (9,022) ​ $ (796) ​ $ (796) Weighted average basic shares outstanding ​ 31,208 ​ 31,208 ​ 31,104 ​ 31,104 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Dilutive effect of share-based awards and warrants ​ ​ ​ ​ — ​ ​ ​ ​ — Weighted average diluted shares outstanding ​ ​ ​ ​ 31,208 ​ ​ ​ ​ 31,104 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Loss per share ​ $ (0.29) ​ $ (0.29) ​ $ (0.03) ​ $ (0.03) Anti-dilutive shares excluded from calculation ​ ​ ​ ​ 4,207 ​ ​ ​ ​ 4,369

EQUITY (Tables)

EQUITY (Tables)	3 Months Ended
	Mar. 31, 2022
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, 2021 53,385 ​ $ 42.79 110,564 ​ $ 41.85 ​ 126,549 ​ $ 36.78 Granted 62,178 ​ ​ 34.65 62,178 ​ ​ 31.86 ​ 81,495 ​ ​ 31.86 Vested (589) ​ ​ 54.55 (35,935) ​ 46.65 ​ (57,840) ​ 37.90 Cancelled, expired or forfeited — ​ ​ — — ​ — ​ (2,655) ​ 34.30 Outstanding as of March 31, 2022 114,974 ​ $ 38.33 136,807 ​ $ 36.05 ​ 147,549 ​ $ 33.67
Summary of stock option activity	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ Average ​ ​ ​ ​ Exercise ​ Shares Price Outstanding as of December 31, 2021 546,594 ​ $ 44.59 Outstanding as of March 31, 2022 546,594 ​ $ 44.59 Exercisable as of March 31, 2022 386,763 ​ $ 47.16
PSUs
Schedule of assumptions for determining the fair value for PSU awards using Monte Carlo simulation models	​ ​ ​ ​ ​ ​ ​ 2022 Stock price on grant date ​ $ 31.86 ​ Expected term ​ 3.0 years Expected volatility ​ ​ 40.1 % Risk-free interest rate ​ 1.0 %

OPERATING SEGMENTS (Tables)

OPERATING SEGMENTS (Tables)	3 Months Ended
	Mar. 31, 2022
OPERATING SEGMENTS
Summary of financial information of our reportable segments	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, 2022 ​ ​ Waste ​ Field ​ Energy ​ ​ ​ ​ ​ ​ $s in thousands Solutions Services Waste Corporate Total Revenue ​ $ 114,766 ​ $ 112,323 ​ $ 13,891 ​ $ — ​ $ 240,980 Depreciation, amortization and accretion ​ $ 10,154 ​ $ 10,592 ​ $ 4,434 ​ $ 819 ​ $ 25,999 Capital expenditures ​ $ 11,274 ​ $ 3,480 ​ $ 581 ​ $ 845 ​ $ 16,180 Total assets ​ $ 808,976 ​ $ 725,894 ​ $ 215,495 ​ $ 68,308 ​ $ 1,818,673 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, 2021 ​ ​ Waste ​ Field ​ Energy ​ ​ ​ ​ ​ ​ $s in thousands Solutions Services Waste Corporate Total Revenue ​ $ 104,142 ​ $ 118,249 ​ $ 6,228 ​ $ — ​ $ 228,619 Depreciation, amortization and accretion ​ $ 11,431 ​ $ 11,371 ​ $ 4,965 ​ $ 784 ​ $ 28,551 Capital expenditures ​ $ 8,145 ​ $ 931 ​ $ 283 ​ $ 255 ​ $ 9,614 Total assets ​ $ 789,277 ​ $ 753,209 ​ $ 228,689 ​ $ 51,977 ​ $ 1,823,152
Reconciliation of Net loss to Adjusted EBITDA and adjusted EBITDA by operating segment	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, $s in thousands 2022 2021 Net loss ​ $ (9,022) ​ $ (796) Income tax benefit ​ ​ (2,014) ​ ​ (1,444) Interest expense ​ ​ 6,821 ​ ​ 7,357 Interest income ​ ​ (229) ​ ​ (273) Foreign currency loss ​ ​ 698 ​ ​ 371 Other income ​ ​ (177) ​ ​ (3,710) Depreciation and amortization of plant and equipment ​ ​ 16,900 ​ ​ 18,234 Amortization of intangible assets ​ ​ 7,872 ​ ​ 9,135 Share-based compensation ​ ​ 1,948 ​ ​ 1,928 Accretion and non-cash adjustment of closure & post-closure liabilities ​ ​ 1,227 ​ ​ 1,182 Business development and integration expenses ​ ​ 5,859 ​ ​ 1,220 Adjusted EBITDA ​ $ 29,883 ​ $ 33,204 ​ Adjusted EBITDA, by operating segment, is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, $s in thousands ​ 2022 2021 Waste Solutions $ 41,418 ​ $ 40,136 Field Services 10,922 ​ 17,137 Energy Waste ​ ​ 4,725 ​ ​ 1,258 Corporate (27,182) ​ (25,327) Total $ 29,883 ​ $ 33,204
Schedule of long-lived assets by geographic location	​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, ​ December 31, $s in thousands ​ 2022 2021 United States ​ $ 846,701 ​ $ 855,200 Canada ​ 66,360 ​ 65,437 EMEA ​ ​ 14,802 ​ ​ 15,604 Other (1) ​ ​ 9,305 ​ ​ 9,716 Total long-lived assets, net ​ $ 937,168 ​ $ 945,957 (1) Includes Mexico, Asia Pacific, and Latin America and Caribbean geographical regions.

REVENUES (Details)

REVENUES (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2022USD ($)segment	Mar. 31, 2021USD ($)
Disaggregation of revenue
Number of reportable segments | segment	3
Revenue	$ 240,980	$ 228,619
Treatment and disposal
Disaggregation of revenue
Revenue	114,165	101,820
Transportation and Logistics
Disaggregation of revenue
Revenue	30,143	23,812
Industrial Services
Disaggregation of revenue
Revenue	29,842	26,665
Small Quantity Generation
Disaggregation of revenue
Revenue	15,039	13,052
Total Waste Management
Disaggregation of revenue
Revenue	10,589	9,882
Remediation
Disaggregation of revenue
Revenue	5,360	11,975
Emergency Response
Disaggregation of revenue
Revenue	31,416	37,355
Other Services
Disaggregation of revenue
Revenue	4,426	4,058
Operating Segment | Environmental Services
Disaggregation of revenue
Revenue	114,766	104,142
Operating Segment | Field & Industrial Services
Disaggregation of revenue
Revenue	112,323	118,249
Operating Segment | Energy Waste
Disaggregation of revenue
Revenue	13,891	6,228
Operating Segment | Treatment and disposal | Environmental Services
Disaggregation of revenue
Revenue	96,280	88,060
Operating Segment | Treatment and disposal | Field & Industrial Services
Disaggregation of revenue
Revenue	10,781	9,977
Operating Segment | Treatment and disposal | Energy Waste
Disaggregation of revenue
Revenue	7,104	3,783
Operating Segment | Transportation and Logistics | Environmental Services
Disaggregation of revenue
Revenue	18,486	16,082
Operating Segment | Transportation and Logistics | Field & Industrial Services
Disaggregation of revenue
Revenue	7,273	6,329
Operating Segment | Transportation and Logistics | Energy Waste
Disaggregation of revenue
Revenue	4,384	1,401
Operating Segment | Industrial Services | Field & Industrial Services
Disaggregation of revenue
Revenue	28,870	26,256
Operating Segment | Industrial Services | Energy Waste
Disaggregation of revenue
Revenue	972	409
Operating Segment | Small Quantity Generation | Field & Industrial Services
Disaggregation of revenue
Revenue	15,039	13,052
Operating Segment | Total Waste Management | Field & Industrial Services
Disaggregation of revenue
Revenue	10,589	9,882
Operating Segment | Remediation | Field & Industrial Services
Disaggregation of revenue
Revenue	5,360	11,975
Operating Segment | Emergency Response | Field & Industrial Services
Disaggregation of revenue
Revenue	31,416	37,355
Operating Segment | Other Services | Field & Industrial Services
Disaggregation of revenue
Revenue	2,995	3,423
Operating Segment | Other Services | Energy Waste
Disaggregation of revenue
Revenue	$ 1,431	$ 635

REVENUES - Treatment and Dispos

REVENUES - Treatment and Disposal Revenue (Details) - Treatment and disposal - T	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Event Business
Disaggregation of revenue
Threshold Tons of Non-recurring projects	1,000
Revenue (in percent)	20.00%	24.00%
Base Business
Disaggregation of revenue
Revenue (in percent)	80.00%	76.00%

REVENUES - Geography (Details)

REVENUES - Geography (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Disaggregation of revenue
Revenue	$ 240,980	$ 228,619
United States
Disaggregation of revenue
Revenue	215,473	196,753
Canada
Disaggregation of revenue
Revenue	18,216	20,247
EMEA
Disaggregation of revenue
Revenue	6,264	10,018
Other
Disaggregation of revenue
Revenue	1,027	1,601
Operating Segment | Environmental Services
Disaggregation of revenue
Revenue	114,766	104,142
Operating Segment | Environmental Services | United States
Disaggregation of revenue
Revenue	97,142	84,474
Operating Segment | Environmental Services | Canada
Disaggregation of revenue
Revenue	17,624	19,668
Operating Segment | Field & Industrial Services
Disaggregation of revenue
Revenue	112,323	118,249
Operating Segment | Field & Industrial Services | United States
Disaggregation of revenue
Revenue	104,440	106,051
Operating Segment | Field & Industrial Services | Canada
Disaggregation of revenue
Revenue	592	579
Operating Segment | Field & Industrial Services | EMEA
Disaggregation of revenue
Revenue	6,264	10,018
Operating Segment | Field & Industrial Services | Other
Disaggregation of revenue
Revenue	1,027	1,601
Operating Segment | Energy Waste
Disaggregation of revenue
Revenue	13,891	6,228
Operating Segment | Energy Waste | United States
Disaggregation of revenue
Revenue	$ 13,891	$ 6,228

REVENUES - Practical Expedients

REVENUES - Practical Expedients (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2022	Dec. 31, 2021
REVENUES
Contract with Customer, Liability, Revenue Recognized	$ 13.5	$ 10.7
Revenue, Practical Expedient, Financing Component	true
Revenue, Practical Expedient, Initial Application and Transition, Nonrestatement of Modified Contract	true

ACCUMULATED OTHER COMPREHENSI_3

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) - Changes in AOCI (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Accumulated other comprehensive income (loss)
Beginning balances	$ 624,324	$ 601,931
Ending balances	631,238	612,703
Foreign Currency Translation
Accumulated other comprehensive income (loss)
Beginning balances	(9,375)	(7,870)
Other comprehensive income before reclassifications, net of tax	1,469	1,439
Other comprehensive income, net	1,469	1,439
Ending balances	(7,906)	(6,431)
Unrealized Gain (Loss) on Interest Rate Hedge
Accumulated other comprehensive income (loss)
Beginning balances	5,181	(6,788)
Other comprehensive income before reclassifications, net of tax	12,746	8,323
Amounts reclassified out of AOCI, net of tax	508	894
Other comprehensive income, net	13,254	9,217
Ending balances	18,435	2,429
Accumulated Other Comprehensive Income (Loss)
Accumulated other comprehensive income (loss)
Beginning balances	(4,194)	(14,658)
Other comprehensive income before reclassifications, net of tax	14,215	9,762
Amounts reclassified out of AOCI, net of tax	508	894
Other comprehensive income, net	14,723	10,656
Ending balances	$ 10,529	$ (4,002)

ACCUMULATED OTHER COMPREHENSI_4

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) -Reclassifications Line Items (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Reclassification adjustments
Interest expense	$ 6,821	$ 7,357
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	1,200
Amounts in AOCI expected to be recognized over the next 12 months, net of taxes	927
Unrealized Gain (Loss) on Interest Rate Hedge | Interest rate swap agreement | Reclassification out of accumulated other comprehensive income
Reclassification adjustments
Interest expense	642	1,100
Interest expense, net of tax	$ 508	$ 894

RECEIVABLES (Details)

RECEIVABLES (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
RECEIVABLES
Trade	$ 186,906	$ 183,747
Unbilled revenue	60,513	62,029
Other	3,834	7,421
Total receivables	251,253	253,197
Allowance for credit losses	(3,020)	(3,043)
Receivables, net	$ 248,233	$ 250,154

FAIR VALUE MEASUREMENTS (Detail

FAIR VALUE MEASUREMENTS (Details) - USD ($) $ in Thousands	1 Months Ended		3 Months Ended
	Mar. 31, 2021	Sep. 30, 2019	Mar. 31, 2021	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2020
Assets measured at fair value on a recurring basis
Minority interest investment			$ (712)
Initial notional amount						$ 500,000
Equity securities without readily determinable fair value
Investment in privately held company					$ 7,900
Variable rate				$ 438,500
Interest rate swap agreement
Assets measured at fair value on a recurring basis
Initial notional amount						$ 430,000
Preferred Stock
Equity securities without readily determinable fair value
Fair value change	$ 3,500
Gain on investment	3,500
Preferred Stock | Other Assets
Assets measured at fair value on a recurring basis
Minority interest investment	$ (712)	$ (7,900)
Recurring
Assets measured at fair value on a recurring basis
Assets fair value disclosure				23,497	8,858
Recurring | Interest rate swap agreement
Assets measured at fair value on a recurring basis
Assets fair value disclosure				21,900	5,022
Recurring | Fixed-income securities
Assets measured at fair value on a recurring basis
Assets fair value disclosure					1,950
Recurring | Money market funds
Assets measured at fair value on a recurring basis
Assets fair value disclosure				1,597	1,886
Recurring | Quoted Prices in Active Markets (Level 1)
Assets measured at fair value on a recurring basis
Assets fair value disclosure				1,597	3,581
Recurring | Quoted Prices in Active Markets (Level 1) | Fixed-income securities
Assets measured at fair value on a recurring basis
Assets fair value disclosure					1,695
Recurring | Quoted Prices in Active Markets (Level 1) | Money market funds
Assets measured at fair value on a recurring basis
Assets fair value disclosure				1,597	1,886
Recurring | Other Observable Inputs (Level 2)
Assets measured at fair value on a recurring basis
Assets fair value disclosure				21,900	5,277
Recurring | Other Observable Inputs (Level 2) | Interest rate swap agreement
Assets measured at fair value on a recurring basis
Assets fair value disclosure				$ 21,900	5,022
Recurring | Other Observable Inputs (Level 2) | Fixed-income securities
Assets measured at fair value on a recurring basis
Assets fair value disclosure					$ 255

PROPERTY AND EQUIPMENT (Details

PROPERTY AND EQUIPMENT (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
PROPERTY AND EQUIPMENT
Total property and equipment	$ 851,817		$ 839,032
Accumulated depreciation and amortization	(396,776)		(382,648)
Property and equipment, net	455,041		456,384
Depreciation and amortization of plant and equipment	16,900	$ 18,234
Cell development costs
PROPERTY AND EQUIPMENT
Total property and equipment	204,067		203,217
Land and improvements
PROPERTY AND EQUIPMENT
Total property and equipment	74,524		74,298
Buildings and improvements
PROPERTY AND EQUIPMENT
Total property and equipment	137,204		138,659
Railcars
PROPERTY AND EQUIPMENT
Total property and equipment	17,299		17,299
Vehicles, vessels and other equipment
PROPERTY AND EQUIPMENT
Total property and equipment	352,925		350,950
Construction in progress
PROPERTY AND EQUIPMENT
Total property and equipment	$ 65,798		$ 54,609

LEASES (Details)

LEASES (Details)	3 Months Ended
	Mar. 31, 2022
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, 2022	Dec. 31, 2021
Assets:
Operating right-of-use assets	$ 54,884	$ 43,607
Finance right-of-use lease assets	15,788	17,290
Total	70,672	60,897
Finance leased assets - accumulated amortization	14,600	13,300
Liabilities:
Operating lease, current	17,780	15,799
Finance lease, current	$ 4,778	$ 4,969
Finance Lease, Liability, Current	Accrued liabilities	Accrued liabilities
Long-term operating lease liabilities	$ 37,991	$ 28,477
Finance lease, long term	$ 11,119	$ 12,108
Finance Lease, Liability, Noncurrent	Other long-term liabilities	Other long-term liabilities
Total	$ 71,668	$ 61,353

LEASES - Lease cost (Details)

LEASES - Lease cost (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Lease cost
Operating lease cost	$ 5,123	$ 5,296
Amortization of leased assets	1,295	1,334
Interest on lease liabilities	265	278
Total	$ 6,683	$ 6,908

LEASES - Supplemental Cash Flow

LEASES - Supplemental Cash Flow information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
LEASES
Operating cash flows from operating leases	$ 4,905	$ 5,151
Operating cash flows from finance leases	265	278
Financing cash flows from finance leases	1,180	1,192
Right-of-use assets obtained in exchange for new operating lease liabilities	$ 16,054	$ 2,074

GOODWILL AND INTANGIBLE ASSET_2

GOODWILL AND INTANGIBLE ASSETS - Goodwill (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2022USD ($)
Changes in goodwill
Balance at the beginning of the period	$ 413,126
Foreign currency translation	400
Balance at the end of the period	413,526
Environmental Services
Changes in goodwill
Balance at the beginning of the period	166,925
Foreign currency translation	278
Balance at the end of the period	167,203
Accumulated Impairment
Accumulated impairment at the beginning	(6,870)
Accumulated impairment at the ending	(6,870)
Energy Waste
Changes in goodwill
Balance at the beginning of the period	399,503
Balance at the end of the period	399,503
Accumulated Impairment
Accumulated impairment at the beginning	(363,900)
Accumulated impairment at the ending	(363,900)
Field & Industrial Services
Changes in goodwill
Balance at the beginning of the period	237,368
Foreign currency translation	122
Balance at the end of the period	237,490
Accumulated Impairment
Accumulated impairment at the beginning	(19,900)
Accumulated impairment at the ending	$ (19,900)

GOODWILL AND INTANGIBLE ASSET_3

GOODWILL AND INTANGIBLE ASSETS - Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Intangible Assets
Amortizing intangible assets, Cost	$ 546,250		$ 545,634
Accumulated amortization	(147,003)		(138,929)
Amortizing intangible assets, Net	399,247		406,705
Total intangible assets, cost	629,130		628,502
Total intangible assets, net	482,127		489,573
Goodwill	413,526		413,126
Amortization of intangible assets	7,872	$ 9,135
Permits and license
Intangible Assets
Non-amortizing intangible assets	82,744		82,734
Tradename
Intangible Assets
Non-amortizing intangible assets	136		134
Permits, licenses and lease
Intangible Assets
Amortizing intangible assets, Cost	175,299		174,959
Accumulated amortization	(28,331)		(27,170)
Amortizing intangible assets, Net	146,968		147,789
Customer relationships
Intangible Assets
Amortizing intangible assets, Cost	340,215		340,065
Accumulated amortization	(94,542)		(87,952)
Amortizing intangible assets, Net	245,673		252,113
Technology - Formulae and processes
Intangible Assets
Amortizing intangible assets, Cost	7,277		7,166
Accumulated amortization	(2,628)		(2,531)
Amortizing intangible assets, Net	4,649		4,635
Customer backlog
Intangible Assets
Amortizing intangible assets, Cost	3,652		3,652
Accumulated amortization	(2,843)		(2,752)
Amortizing intangible assets, Net	809		900
Tradename
Intangible Assets
Amortizing intangible assets, Cost	10,390		10,390
Accumulated amortization	(10,390)		(10,390)
Developed software
Intangible Assets
Amortizing intangible assets, Cost	2,907		2,903
Accumulated amortization	(2,552)		(2,475)
Amortizing intangible assets, Net	355		428
Non-compete agreements
Intangible Assets
Amortizing intangible assets, Cost	5,583		5,573
Accumulated amortization	(5,256)		(5,211)
Amortizing intangible assets, Net	327		362
Internet domain and website
Intangible Assets
Amortizing intangible assets, Cost	536		536
Accumulated amortization	(220)		(213)
Amortizing intangible assets, Net	316		323
Database
Intangible Assets
Amortizing intangible assets, Cost	391		390
Accumulated amortization	(241)		(235)
Amortizing intangible assets, Net	150		155
Field & Industrial Services
Intangible Assets
Goodwill	$ 237,490		$ 237,368

DEBT - Schedule (Details)

DEBT - Schedule (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021	Aug. 06, 2019
Long-term debt
Unamortized term loan discount and debt issuance costs	$ (5,231)	$ (5,516)
Total debt	737,644	738,484
Current portion of long-term debt	(3,359)	(3,359)
Long-term debt	734,285	735,125
Credit agreement
Long-term debt
Loan amount	303,000	303,000
Term Loan
Long-term debt
Loan amount	$ 439,875	$ 441,000	$ 400,000

DEBT - Paragraph (Details)

DEBT - Paragraph (Details) $ in Thousands	Jun. 29, 2021	Jun. 26, 2020	Nov. 01, 2019USD ($)	Aug. 06, 2019USD ($)	Apr. 18, 2017USD ($)	Mar. 31, 2020USD ($)	Mar. 31, 2022USD ($)	Dec. 31, 2021USD ($)
DEBT
Notional amount						$ 500,000
Interest rate swap agreement
DEBT
Notional amount						$ 430,000
Percentage of outstanding debt						58.00%
Net loss related to terminated swap						$ 1,800
Credit agreement
DEBT
Maximum borrowing capacity					$ 500,000
Contractual term					5 years
Accordion feature			$ 250,000
Amount outstanding							$ 303,000
Effective interest rate (as a percent)							3.94%
Loan amount							$ 303,000	$ 303,000
Availability for borrowings under line of credit							$ 27,700
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%
Equity interest in domestic subsidiaries pledged as security (as a percent)					100.00%
Percentage of EBITDA plus certain additional amounts used to determine additional borrowing capacity			100.00%
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)							0.40%
Credit Agreement, Letter Of Credit
DEBT
Line of credit issued in the form of a standby letters of credit							$ 12,200
Credit Agreement, Swingline Loans
DEBT
Maximum borrowing capacity			$ 40,000
Credit Agreement, Swingline Loans | Sweep Arrangements
DEBT
Maximum borrowing capacity							40,000
Amount outstanding							0
Term Loan
DEBT
Maximum borrowing capacity			$ 450,000
Contractual term			7 years
Loan amount				$ 400,000			$ 439,875	$ 441,000
Increase in capacity			$ 50,000
Required annual principal repayment (as a percent)			1.00%
Effective interest rate (as a percent)							2.91%
Term Loan | Maximum
DEBT
Commitment fee (as a percent)	0.375%
Term Loan | LIBOR
DEBT
Percentage points added to the reference rate	2.25%		2.25%
Term Loan | Base rate
DEBT
Percentage points added to the reference rate	1.25%		1.25%

DEBT - Loan Interest Margin (De

DEBT - Loan Interest Margin (Details)	Jun. 29, 2021	Nov. 01, 2019	Apr. 18, 2017	Mar. 31, 2022
Credit agreement
DEBT
Minimum consolidated senior secured leverage ratio			3
Maximum consolidated senior secured leverage ratio			4.50
Credit agreement | Maximum
DEBT
Commitment fee (as a percent)				0.40%
Credit agreement | Equal to or greater than 4.50 to 1.00
DEBT
Minimum consolidated senior secured leverage ratio	4.50		4.50
Credit agreement | Equal to or greater than 4.00 to 1.00, but less than 4.50 to 1.00
DEBT
Minimum consolidated senior secured leverage ratio	4		4
Maximum consolidated senior secured leverage ratio	4.50		4.50
Credit agreement | Equal to or greater than 3.25 to 1.00, but less than 4.00 to 1.00
DEBT
Minimum consolidated senior secured leverage ratio			3.25
Maximum consolidated senior secured leverage ratio			4
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 4.50 to 1.00
DEBT
Percentage points added to the reference rate			2.50%
Credit agreement | LIBOR | Equal to or greater than 4.00 to 1.00, but less than 4.50 to 1.00
DEBT
Percentage points added to the reference rate			2.25%
Credit agreement | LIBOR | Equal to or greater than 3.25 to 1.00, but less than 4.00 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 4.50 to 1.00
DEBT
Percentage points added to the reference rate			1.50%
Credit agreement | Base rate | Equal to or greater than 4.00 to 1.00, but less than 4.50 to 1.00
DEBT
Percentage points added to the reference rate			1.25%
Credit agreement | Base rate | Equal to or greater than 3.25 to 1.00, but less than 4.00 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%
Term Loan | Maximum
DEBT
Commitment fee (as a percent)	0.375%
Term Loan | Equal to or greater than 4.50 to 1.00 | Maximum
DEBT
Commitment fee (as a percent)	0.40%
Term Loan | LIBOR
DEBT
Percentage points added to the reference rate	2.25%	2.25%
Term Loan | LIBOR | Equal to or greater than 4.50 to 1.00
DEBT
Percentage points added to the reference rate	2.50%
Term Loan | LIBOR | Step Up Rate Based On Credit Ratings
DEBT
Percentage points added to the reference rate		2.50%
Term Loan | Base rate
DEBT
Percentage points added to the reference rate	1.25%	1.25%
Term Loan | Base rate | Equal to or greater than 4.50 to 1.00
DEBT
Percentage points added to the reference rate	1.50%
Term Loan | Base rate | Step Up Rate Based On Credit Ratings
DEBT
Percentage points added to the reference rate		1.50%

DEBT - Leverage Ratio (Details)

DEBT - Leverage Ratio (Details)	Jun. 26, 2020	Aug. 06, 2019
Credit agreement
DEBT
Total leverage ratio	4	4

CLOSURE AND POST-CLOSURE OBLI_3

CLOSURE AND POST-CLOSURE OBLIGATIONS - Rollforward (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Changes to reported closure and post-closure obligations
Closure and post-closure obligations, beginning of year	$ 98,920
Accretion expense	1,227	$ 1,182
Payments	(517)
Foreign currency translation	24
Closure and post-closure obligations, end of year	99,654
Less current portion	(6,322)		$ (5,771)
Long-term portion	$ 93,332		$ 93,149

INCOME TAXES (Details)

INCOME TAXES (Details) - USD ($)	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
INCOME TAXES
Income tax benefit	$ (2,014,000)	$ (1,444,000)
Effective tax rate (as a percent)	18.20%	64.50%
Unrecognized Tax Benefits	$ 269,000		$ 256,000
Possible reduction in the provision for income taxes if the unrecognized tax benefits were recognized	269,000
Penalties accrued on unrecognized tax benefits	$ 0

LOSS PER SHARE (Details)

LOSS PER SHARE (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
LOSS PER SHARE
Net loss	$ (9,022)	$ (796)
Basic
Weighted average basic shares outstanding	31,208	31,104
Loss per share (in dollars per share)	$ (0.29)	$ (0.03)
Diluted
Net loss, diluted	$ (9,022)	$ (796)
Weighted average diluted shares outstanding	31,208	31,104
Loss per share (in dollars per share)	$ (0.29)	$ (0.03)
Anti-dilutive shares excluded from calculation	4,207	4,369

EQUITY - Omnibus Incentive Plan

EQUITY - Omnibus Incentive Plan (Details) - Omnibus Plan - shares	Mar. 31, 2022	May 27, 2015
Stock-Based Compensation Plans
Number of shares authorized for grant		3,272,000
Number of shares available for future grant	1,885,810
Number of shares outstanding	0

EQUITY - PSUs, Restricted Stock

EQUITY - PSUs, Restricted Stock and RSU (Details) - USD ($)	Jan. 03, 2022	Mar. 31, 2022	Dec. 31, 2021
Assumptions used in Monte Carlo simulation
Common stock, shares issued		31,512,000	31,512,000
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)		53,385
Granted (in shares)	62,178	62,178
Vested (in shares)		(589)
Outstanding at the end of the year (in shares)		114,974
Weighted Average Grant Date Fair Value
Outstanding at the beginning of the period (in dollars per share)		$ 42.79
Granted (in dollars per share)		34.65
Vested (in dollars per share)		54.55
Outstanding at the end of the period (in dollars per share)		$ 38.33
Additional disclosures
Total fair value of restricted stock vested	$ 34.65
Assumptions used in Monte Carlo simulation
Stock price on grant date		$ 31.86
Expected term (years)		3 years
Expected volatility (as a percent)		40.10%
Risk-free interest rate (as a percent)		1.00%
Common stock, shares issued		589
PSUs | Minimum
Stock-Based Compensation Plans
Percentage payout rate	0.00%
PSUs | Maximum
Stock-Based Compensation Plans
Percentage payout rate	250.00%
PSUs | Performance requirement one
Stock-Based Compensation Plans
Vesting period	1 year
PSUs | Performance requirement two
Stock-Based Compensation Plans
Vesting period	3 years
Restricted stock
Shares
Outstanding at the beginning of the year (in shares)		110,564
Granted (in shares)		62,178
Vested (in shares)		(35,935)
Outstanding at the end of the year (in shares)		136,807
Weighted Average Grant Date Fair Value
Outstanding at the beginning of the period (in dollars per share)		$ 41.85
Granted (in dollars per share)		31.86
Vested (in dollars per share)		46.65
Outstanding at the end of the period (in dollars per share)		$ 36.05
RSUs
Shares
Outstanding at the beginning of the year (in shares)		126,549
Granted (in shares)		81,495
Vested (in shares)		(57,840)
Cancelled, expired or forfeited (in shares)		(2,655)
Outstanding at the end of the year (in shares)		147,549
Weighted Average Grant Date Fair Value
Outstanding at the beginning of the period (in dollars per share)		$ 36.78
Granted (in dollars per share)		31.86
Vested (in dollars per share)		37.90
Cancelled, expired or forfeited (in dollars per share)		34.30
Outstanding at the end of the period (in dollars per share)		$ 33.67

EQUITY - Stock Options (Details

EQUITY - Stock Options (Details) - Stock options - $ / shares	Mar. 31, 2022	Dec. 31, 2021
Shares
Outstanding (in shares)	546,594	546,594
Exercisable at the end of the period (in shares)	386,763
Weighted Average Exercise Price
Outstanding (in dollars per share)	$ 44.59	$ 44.59
Exercisable at the end of the period (in dollars per share)	$ 47.16

EQUITY - Treasury Stock (Detail

EQUITY - Treasury Stock (Details) - $ / shares	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Dividends
Dividends paid per share (in dollars per share)	$ 0	$ 0
Share repurchase program related to net share settlement
Treasury Stock
Repurchase of common stock (in shares)	379
Average cost of repurchase (in dollars per share)	$ 31.89
Restricted stock | Omnibus Plan
Treasury Stock
Issuance of restricted stock from treasury stock (in shares)	102,193
Average cost (in dollars per share)	$ 43.91

EQUITY - Warrants (Details)

EQUITY - Warrants (Details)	3 Months Ended
	Mar. 31, 2022$ / sharesshares
Warrants
Number of warrants (in shares) | shares	3,772,753
Number of shares each warrant is entitled to purchase | shares	1
Exercise price	$ 58.67
Redemption price of warrants	$ 0.01
Minimum number of day for written prior notice for redemption	30 days
Share price of common stock required for redemption	$ 91.84
Number of trading days share price equals or exceeds required price within 30 consecutive trading days for redemption	20 days
Number of consecutive trading days	30 days

COMMITMENTS AND CONTINGENCIES -

COMMITMENTS AND CONTINGENCIES - Litigation and Regulatory Proceedings (Details)	Jan. 10, 2020USD ($)
Occupational Safety and Health Review Commission
Litigation and Regulatory Proceedings
Settlement	$ 50,000

OPERATING SEGMENTS - Summarized

OPERATING SEGMENTS - Summarized Financial Information (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2022USD ($)segment	Mar. 31, 2021USD ($)	Dec. 31, 2021USD ($)
OPERATING SEGMENTS
Number of reportable segments | segment	3
Revenue	$ 240,980	$ 228,619
Depreciation, amortization and accretion	25,999	28,551
Capital expenditures	16,180	9,614
Total assets	1,818,673	1,823,152	$ 1,805,398
Corporate
OPERATING SEGMENTS
Depreciation, amortization and accretion	819	784
Capital expenditures	845	255
Total assets	68,308	51,977
Environmental Services | Operating Segment
OPERATING SEGMENTS
Revenue	114,766	104,142
Depreciation, amortization and accretion	10,154	11,431
Capital expenditures	11,274	8,145
Total assets	808,976	789,277
Field & Industrial Services | Operating Segment
OPERATING SEGMENTS
Revenue	112,323	118,249
Depreciation, amortization and accretion	10,592	11,371
Capital expenditures	3,480	931
Total assets	725,894	753,209
Energy Waste | Operating Segment
OPERATING SEGMENTS
Revenue	13,891	6,228
Depreciation, amortization and accretion	4,434	4,965
Capital expenditures	581	283
Total assets	$ 215,495	$ 228,689

OPERATING SEGMENTS - Reconcilia

OPERATING SEGMENTS - Reconciliation of EBITDA (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Reconciliation of Net Income to Adjusted EBITDA
Net loss	$ (9,022)	$ (796)
Income tax benefit	(2,014)	(1,444)
Interest expense	6,821	7,357
Interest income	(229)	(273)
Foreign currency loss	698	371
Other income	(177)	(3,710)
Depreciation and amortization of plant and equipment	16,900	18,234
Amortization of intangibles assets	7,872	9,135
Share-based compensation	1,948	1,928
Accretion and non-cash adjustment of closure & post-closure liabilities	1,227	1,182
Business development and integration expenses	5,859	1,220
Adjusted EBITDA	29,883	33,204
Operating Segment | Environmental Services
Reconciliation of Net Income to Adjusted EBITDA
Adjusted EBITDA	41,418	40,136
Operating Segment | Field & Industrial Services
Reconciliation of Net Income to Adjusted EBITDA
Adjusted EBITDA	10,922	17,137
Operating Segment | Energy Waste
Reconciliation of Net Income to Adjusted EBITDA
Adjusted EBITDA	4,725	1,258
Corporate
Reconciliation of Net Income to Adjusted EBITDA
Adjusted EBITDA	$ (27,182)	$ (25,327)

OPERATING SEGMENTS - Revenue an

OPERATING SEGMENTS - Revenue and Long-lived Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Revenue and Long-Lived Assets Outside of the United States
Total long- lived assets	$ 937,168	$ 945,957
United States
Revenue and Long-Lived Assets Outside of the United States
Total long- lived assets	846,701	855,200
Canada
Revenue and Long-Lived Assets Outside of the United States
Total long- lived assets	66,360	65,437
EMEA
Revenue and Long-Lived Assets Outside of the United States
Total long- lived assets	14,802	15,604
Other
Revenue and Long-Lived Assets Outside of the United States
Total long- lived assets	$ 9,305	$ 9,716