Clean Harbors (CLH) 10-Q 3 Aug 16 2016 Q2 Quarterly report Financial data

DOCUMENT AND ENTITY INFORMATION

DOCUMENT AND ENTITY INFORMATION - shares	6 Months Ended
	Jun. 30, 2016	Jul. 29, 2016
Document and Entity Information [Abstract]
Entity Registrant Name	CLEAN HARBORS INC
Entity Central Index Key	822,818
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Jun. 30, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q2
Amendment Flag	false
Entity Common Stock, Shares Outstanding		57,495,468

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 352,923	$ 184,708
Accounts receivable, net of allowances aggregating $28,436 and $31,426, respectively	503,749	496,004
Unbilled accounts receivable	29,119	25,940
Deferred costs	21,261	18,758
Inventories and supplies	162,404	149,521
Prepaid expenses and other current assets	49,678	46,265
Total current assets	1,119,134	921,196
Property, plant and equipment, net	1,594,987	1,532,467
Other assets:
Deferred financing costs	1,412	1,847
Goodwill	461,491	453,105
Permits and other intangibles, net	492,224	506,818
Other	23,133	15,995
Total other assets	978,260	977,765
Total assets	3,692,381	3,431,428
Current liabilities:
Accounts payable	222,302	241,183
Deferred revenue	70,263	61,882
Accrued expenses	203,813	193,660
Current portion of closure, post-closure and remedial liabilities	24,043	20,395
Total current liabilities	520,421	517,120
Other liabilities:
Closure and post-closure liabilities, less current portion of $8,043 and $7,229, respectively	51,143	49,020
Remedial liabilities, less current portion of $16,000 and $13,166, respectively	114,291	118,826
Long-term obligations	1,631,881	1,382,543
Deferred taxes, unrecognized tax benefits and other long-term liabilities	258,302	267,637
Total other liabilities	2,055,617	1,818,026
Commitments and contingent liabilities
Stockholders’ equity:
Common Stock, $.01 par value: Authorized 80,000,000; shares issued and outstanding 57,495,095 and 57,593,201 shares, respectively	575	576
Shares held under employee participation plan	(469)	(469)
Additional paid-in capital	730,709	738,401
Accumulated other comprehensive loss	(210,233)	(254,892)
Accumulated earnings	595,761	612,666
Total stockholders’ equity	1,116,343	1,096,282
Total liabilities and stockholders’ equity	$ 3,692,381	$ 3,431,428

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Account Receivable, allowances aggregating	$ 28,436	$ 31,426
Closure and post-closure liabilities, current portion	8,043	7,229
Remedial liabilities, current portion	$ 16,000	$ 13,166
Common stock, par value (in USD per share)	$ 0.01	$ 0.01
Common stock, authorized shares (in shares)	80,000,000	80,000,000
Common stock, issued shares (in shares)	57,495,095	57,593,201
Common stock, outstanding shares (in shares)	57,495,095	57,593,201

UNAUDITED CONSOLIDATED STATEMEN

UNAUDITED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Revenues:
Service revenues	$ 584,562	$ 801,347	$ 1,114,793	$ 1,397,677
Product revenues	112,948	134,881	218,800	271,050
Total revenues	697,510	936,228	1,333,593	1,668,727
Cost of revenues (exclusive of items shown separately below)
Service revenues	388,684	544,870	762,670	961,260
Product revenues	91,318	107,818	181,611	237,935
Total cost of revenues	480,002	652,688	944,281	1,199,195
Selling, general and administrative expenses	107,063	120,418	211,547	228,133
Accretion of environmental liabilities	2,548	2,599	5,053	5,218
Depreciation and amortization	73,393	67,773	142,295	136,129
Goodwill impairment charge	0	31,992	0	31,992
Income (loss) from operations	34,504	60,758	30,417	68,060
Other expense	(189)	(660)	(539)	(251)
Interest expense, net of interest income of $225, $188, $375 and $339, respectively	(21,647)	(19,249)	(40,627)	(38,687)
Income (loss) before provision for income taxes	12,668	40,849	(10,749)	29,122
Provision for income taxes	8,702	30,454	6,156	25,816
Net income (loss)	$ 3,966	$ 10,395	$ (16,905)	$ 3,306
Earnings (loss) per share:
Basic (in USD per share)	$ 0.07	$ 0.18	$ (0.29)	$ 0.06
Diluted (in USD per share)	$ 0.07	$ 0.18	$ (0.29)	$ 0.06
Shares used to compute earnings (loss) per share - Basic (in shares)	57,549	58,590	57,599	58,732
Shares used to compute earnings (loss) per share - Diluted (in shares)	57,678	58,710	57,599	58,832

UNAUDITED CONSOLIDATED STATEME5

UNAUDITED CONSOLIDATED STATEMENTS OF OPERATIONS (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Income Statement [Abstract]
Interest expense	$ 225	$ 188	$ 375	$ 339

UNAUDITED CONSOLIDATED STATEME6

UNAUDITED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 3,966	$ 10,395	$ (16,905)	$ 3,306
Other comprehensive (loss) income:
Foreign currency translation adjustments	(1,178)	12,231	44,659	(65,172)
Other comprehensive (loss) income	(1,178)	12,231	44,659	(65,172)
Comprehensive income (loss)	$ 2,788	$ 22,626	$ 27,754	$ (61,866)

UNAUDITED CONSOLIDATED STATEME7

UNAUDITED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Cash flows from operating activities:
Net income (loss)	$ (16,905)	$ 3,306
Adjustments to reconcile net income to net cash from operating activities:
Depreciation and amortization	142,295	136,129
Goodwill impairment charge	0	31,992
Allowance for doubtful accounts	3,228	4,536
Amortization of deferred financing costs and debt discount	1,772	1,639
Accretion of environmental liabilities	5,053	5,218
Changes in environmental liability estimates	(315)	887
Deferred income taxes	(6,521)	(908)
Stock-based compensation	4,739	6,146
Excess tax benefit of stock-based compensation	(2)	(102)
Net tax deficiency on stock based awards	(603)	(72)
Other expense	1,049	251
Environmental expenditures	(6,454)	(11,532)
Changes in assets and liabilities, net of acquisitions
Accounts receivable and unbilled accounts receivable	993	(133,031)
Inventories and supplies	(1,113)	17,694
Other current assets	(4,789)	(816)
Accounts payable	(8,397)	108,639
Other current and long-term liabilities	6,021	23,839
Net cash from operating activities	120,051	193,815
Cash flows used in investing activities:
Additions to property, plant and equipment	(123,529)	(124,145)
Proceeds from sales of fixed assets	2,668	2,646
Acquisitions, net of cash acquired	(58,989)	(79,610)
Additions to intangible assets, including costs to obtain or renew permits	(973)	(3,088)
Purchases of available-for-sale securities	(598)	0
Net cash used in investing activities	(181,421)	(204,197)
Cash flows from (used in) financing activities:
Change in uncashed checks	(11,022)	(22,160)
Proceeds from exercise of stock options	184	397
Issuance of restricted shares, net of shares remitted	(1,879)	(1,837)
Repurchases of common stock	(10,134)	(32,203)
Deferred financing costs paid	(2,614)	0
Payments on capital leases	0	(471)
Excess tax benefit of stock-based compensation	2	102
Issuance of senior secured notes, including premium	250,625	0
Net cash from (used in) financing activities	225,162	(56,172)
Effect of exchange rate change on cash	4,423	(6,704)
Increase (decrease) in cash and cash equivalents	168,215	(73,258)
Cash and cash equivalents, beginning of period	184,708	246,879
Cash and cash equivalents, end of period	352,923	173,621
Cash payments for interest and income taxes:
Interest paid	44,275	37,411
Income taxes paid	23,872	3,068
Non-cash investing and financing activities:
Property, plant and equipment accrued	24,187	34,799
Receivable for estimated purchase price adjustment	$ 0	$ 2,518

UNAUDITED CONSOLIDATED STATEME8

UNAUDITED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - 6 months ended Jun. 30, 2016 - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Shares Held Under Employee Participation Plan	Additional Paid-in Capital	Accumulated Other Comprehensive Loss	Accumulated Earnings
Balance at beginning of period at Dec. 31, 2015	$ 1,096,282	$ 576	$ (469)	$ 738,401	$ (254,892)	$ 612,666
Balance beginning of period (in shares) at Dec. 31, 2015		57,593
Increase (Decrease) in Stockholders' Equity
Net income (loss)	(16,905)					(16,905)
Other comprehensive income	44,659				44,659
Stock-based compensation	4,739			4,739
Issuance of restricted shares, net of shares remitted	(1,879)	$ 1		(1,880)
Issuance of restricted shares, net of shares remitted (in shares)		97
Repurchases of common stock	$ (10,134)	$ (2)		(10,132)
Repurchases of common stock (in shares)	(200)	(203)
Exercise of stock options (in shares)		8
Exercise of stock options	$ 184			184
Net tax deficiency on stock based awards	(603)			(603)
Balance at end of period at Jun. 30, 2016	$ 1,116,343	$ 575	$ (469)	$ 730,709	$ (210,233)	$ 595,761
Balance ending of period (in shares) at Jun. 30, 2016		57,495

UNAUDITED CONSOLIDATED STATEME9

UNAUDITED CONSOLIDATED STATEMENTS OF STOCKHOLDERS'S EQUITY (PARENTHETICAL) - $ / shares	Jun. 30, 2016	Dec. 31, 2015
Statement of Stockholders' Equity [Abstract]
Common stock, par value (in USD per share)	$ 0.01	$ 0.01

BASIS OF PRESENTATION

BASIS OF PRESENTATION	6 Months Ended
	Jun. 30, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
BASIS OF PRESENTATION	BASIS OF PRESENTATION The accompanying consolidated interim financial statements are unaudited and include the accounts of Clean Harbors, Inc. and its subsidiaries (collectively, “Clean Harbors,” the “Company” or "we") and have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission (the “SEC”) and, in the opinion of management, include all adjustments which are of a normal recurring nature, necessary for a fair presentation of the financial position, results of operations, and cash flows for the periods presented. Management has made estimates and assumptions affecting the amounts reported in the Company's consolidated interim financial statements and accompanying footnotes, actual results could differ from those estimates and judgments. The results for interim periods are not necessarily indicative of results for the entire year or any other interim periods. The financial statements presented herein should be read in connection with the financial statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2015 , which includes the audited consolidated balance sheet as of December 31, 2015 from which the one presented herein was derived.

SIGNIFICANT ACCOUNTING POLICIES

SIGNIFICANT ACCOUNTING POLICIES	6 Months Ended
	Jun. 30, 2016
Accounting Policies [Abstract]
SIGNIFICANT ACCOUNTING POLICIES	SIGNIFICANT ACCOUNTING POLICIES The Company's significant accounting policies are described in Note 2, "Significant Accounting Policies," in the Company's Annual Report on Form 10-K for the year ended December 31, 2015 . There have been no material changes in these policies or their application. Recent Accounting Pronouncements Standards implemented In February 2015, the Financial Accounting Standards Board ("FASB") issued Accounting Standard Update ("ASU") 2015-02, Consolidation (Topic 810) . The amendment provides guidance regarding amendments to the consolidation analysis. The adoption of ASU 2015-02 as of January 1, 2016 did not have an impact on the Company's consolidated financial statements. In September 2015, FASB issued ASU 2015-16, Business Combinations (Topic 805) . The amendment provides guidance to simplify the accounting for adjustments made to provisional amounts recognized in a business combination. This amendment eliminates the requirement to retrospectively account for those adjustments. ASU 2015-16 should be applied prospectively to adjustments to provisional amounts that occur after the effective date of this update. The adoption of ASU 2015-16 as of January 1, 2016 did not have an impact on the Company's consolidated financial statements. Standards to be implemented The Company is currently evaluating the impact that the below standards to be implemented will have on the Company's consolidated financial statements. In February 2016, FASB issued ASU 2016-02, Leases (Topic 842) . The amendment increases transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet and disclosing key information about leasing arrangements. ASU 2016-02 should be applied using a modified retrospective approach and early adoption is permitted. The amendments in this update are effective for annual reporting periods (including interim reporting periods within those periods) beginning after December 15, 2018. In March 2016, FASB issued ASU 2016-08, Revenue from Contracts with Customers (Topic 606) . ASU 2016-08 reduces the potential for diversity in practice arising from inconsistent application of the principal versus agent guidance, as well as the cost and complexity of applying Topic 606 both at transition and on an ongoing basis. The effective date and transition requirements for the amendments in this update are the same as the effective date and transition requirements of Update 2014-09, Revenue from Contracts with Customers (Topic 606) . In March 2016, FASB issued ASU 2016-09, Compensation - Stock Compensation (Topic 718) . The amendment simplifies several aspects of the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities and classification on the statement of cash flows. ASU 2016-09 allows for retrospective or prospective application and early adoption is permitted. The amendments in this update are effective for annual reporting periods (including interim reporting periods within those periods) beginning after December 15, 2016. In April 2016, FASB issued ASU 2016-10, Revenue from Contracts with Customers (Topic 606) . ASU 2016-10 reduces the potential for diversity in initial application, as well as the cost and complexity of applying Topic 606 both at transition and on an ongoing basis. The effective date and transition requirements for the amendments in this update are the same as the effective date and transition requirements of Update 2014-09, Revenue from Contracts with Customers (Topic 606) . In May 2016, FASB issued ASU 2016-12, Revenue from Contracts with Customers (Topic 606) . ASU 2016-12 provided narrow scope improvements and practical expedients on assessing collectability, presentation of sales taxes, noncash consideration, and completed contracts and contract modifications at transition. The effective date and transition requirements for the amendments in this update are the same as the effective date and transition requirements of Update 2014-09, Revenue from Contracts with Customers (Topic 606) .

BUSINESS COMBINATIONS

BUSINESS COMBINATIONS	6 Months Ended
	Jun. 30, 2016
Business Combinations [Abstract]
BUSINESS COMBINATIONS	BUSINESS COMBINATIONS 2016 Acquisitions During the first six months of 2016 , the Company acquired (i) an oil re-refinery facility located in Nevada from Vertex Energy, Inc. and (ii) a blending and packaging company with operations located in New Orleans and Toronto, Canada. The combined purchase price for the two acquisitions was approximately $59.0 million in cash, subject to customary post-closing adjustments . The acquisitions expand the Company's re-refinery network and blending and packaging capabilities within its Kleen Performance Products segment. The combined amount of revenue from the acquisitions included in the Company's results of operations for each of the three and six months ended June 30, 2016 was approximately $12.1 million , respectively. During the three and six months ended June 30, 2016 , the Company incurred acquisition-related costs of approximately $0.4 million and $0.5 million , respectively, in connection with the transactions which are included in selling, general and administrative expenses in the consolidated statements of income. Results of the acquired companies or assets are included within the Kleen Performance Products segment. The allocation of the purchase price was based on preliminary estimates of the fair value of assets acquired and liabilities assumed as of the acquisition dates. Given the recent timing of these transactions the Company is continuing to obtain information to complete its valuation of these accounts and the associated tax accounting. The components and preliminary allocation of the purchase price consist of the following amounts (in thousands): At Acquisition Dates Measurement Period Adjustments At Acquisition Dates As Reported Accounts receivable $ 9,186 $ — $ 9,186 Inventories and supplies 9,431 — 9,431 Prepaid and other current assets 433 — 433 Property, plant and equipment 45,781 (1,477 ) 44,304 Permits and other intangibles 1,205 900 2,105 Current liabilities (7,119 ) — (7,119 ) Deferred taxes, unrecognized tax benefits and other long-term liabilities (548 ) — (548 ) Total identifiable net assets 58,369 (577 ) 57,792 Goodwill 620 577 1,197 Total $ 58,989 $ — $ 58,989 Pro forma revenue and earnings amounts on a combined basis as if these acquisitions had been completed on January 1, 2015 are immaterial to the consolidated financial statements of the Company since that date. 2015 Acquisitions Thermo Fluids Inc. On April 11, 2015 , the Company completed the acquisition of Heckmann Environmental Services, Inc. (“HES”) and Thermo Fluids Inc. (“TFI”), a wholly-owned subsidiary of HES. The acquisition was accomplished through a purchase by Safety-Kleen, Inc., a wholly-owned subsidiary of the Company, of all of the issued and outstanding shares of HES from Nuverra Environmental Solutions, Inc. HES is a holding company that does not conduct any operations. TFI provides environmental services, including used oil recycling, used oil filter recycling, antifreeze products, parts washers and solvent recycling, and industrial waste management services, including vacuum services, remediation, lab pack and hazardous waste management. The Company acquired TFI for a purchase price of $79.3 million . The acquisition was financed with cash on hand and expands the Company’s environmental services customer base while also complimenting the SK Environmental Services network and presence in the western United States. Results of TFI since acquisition have been included within the SK Environmental Services segment. The allocation of the purchase price was based on estimates of the fair value of assets acquired and liabilities assumed as of April 11, 2015 . The Company believes that such information provides a reasonable basis for estimating the fair values of assets acquired and liabilities assumed. The Company has finalized the purchase accounting for the acquisition of TFI. The following table summarizes the recognized amounts of assets acquired and liabilities assumed at April 11, 2015 (in thousands): Preliminary Allocations Measurement Period Adjustments Final Allocations Accounts receivable $ 7,109 $ 192 $ 7,301 Inventories and supplies 1,791 — 1,791 Prepaid and other current assets 1,749 (1,084 ) 665 Property, plant and equipment 30,468 (2,827 ) 27,641 Permits and other intangibles 20,000 (1,900 ) 18,100 Current liabilities (5,859 ) (25 ) (5,884 ) Closure and post-closure liabilities (1,676 ) (657 ) (2,333 ) Deferred taxes, unrecognized tax benefits and other long-term liabilities (13,081 ) 3,907 (9,174 ) Total identifiable net assets 40,501 (2,394 ) 38,107 Goodwill 36,591 4,638 41,229 Total $ 77,092 $ 2,244 $ 79,336 Pro forma revenue and earnings amounts on a combined basis as if TFI had been acquired on January 1, 2015 are immaterial to the consolidated financial statements of the Company since that date. Other 2015 Acquisition In December 2015, the Company acquired certain assets and assumed certain defined liabilities of a privately owned company for approximately $14.7 million in cash. That company specializes in the collection and recycling of used oil filters and was a service provider to the SK Environmental Services segment prior to the acquisition. The acquired assets have been integrated into the SK Environmental Services segment. In connection with this acquisition a preliminary goodwill amount of $ 7.4 million was recognized.

INVENTORIES AND SUPPLIES

INVENTORIES AND SUPPLIES	6 Months Ended
	Jun. 30, 2016
Inventory Disclosure [Abstract]
INVENTORIES AND SUPPLIES	INVENTORIES AND SUPPLIES Inventories and supplies consisted of the following (in thousands): June 30, 2016 December 31, 2015 Oil and oil products $ 46,671 $ 33,603 Supplies and drums 78,168 78,132 Solvent and solutions 8,756 8,868 Modular camp accommodations 15,298 15,126 Other 13,511 13,792 Total inventories and supplies $ 162,404 $ 149,521 As of June 30, 2016 and December 31, 2015 , other inventories consisted primarily of cleaning fluids, such as absorbents and wipers, and automotive fluids, such as windshield washer fluid and antifreeze.

PROPERTY, PLANT AND EQUIPMENT

PROPERTY, PLANT AND EQUIPMENT	6 Months Ended
	Jun. 30, 2016
Property, Plant and Equipment [Abstract]
PROPERTY, PLANT AND EQUIPMENT	PROPERTY, PLANT AND EQUIPMENT Property, plant and equipment consisted of the following (in thousands): June 30, 2016 December 31, 2015 Land $ 104,533 $ 100,582 Asset retirement costs (non-landfill) 12,187 12,434 Landfill assets 144,540 136,624 Buildings and improvements 354,470 344,209 Camp equipment 158,394 149,361 Vehicles 538,170 500,619 Equipment 1,414,946 1,328,915 Furniture and fixtures 5,528 5,337 Construction in progress 146,199 113,657 2,878,967 2,691,738 Less - accumulated depreciation and amortization 1,283,980 1,159,271 Total property, plant and equipment, net $ 1,594,987 $ 1,532,467 Interest in the amount of $1.3 million and $2.5 million was capitalized to fixed assets during the three and six months ended June 30, 2016 , respectively. Interest in the amount of $0.4 million and $0.6 million was capitalized to fixed assets during the three and six months ended June 30, 2015 , respectively. Depreciation expense, inclusive of landfill amortization was $63.5 million and $122.8 million for the three and six months ended June 30, 2016 , respectively. Depreciation expense, inclusive of landfill amortization was $58.9 million and $116.3 million for the three and six months ended June 30, 2015 , respectively.

GOODWILL AND OTHER INTANGIBLE A

GOODWILL AND OTHER INTANGIBLE ASSETS	6 Months Ended
	Jun. 30, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
GOODWILL AND OTHER INTANGIBLE ASSETS	GOODWILL AND OTHER INTANGIBLE ASSETS The changes in goodwill for the six months ended June 30, 2016 were as follows (in thousands): Technical Services Industrial & Field Services Kleen Performance Products SK Environmental Services Lodging Services Oil and Gas Field Services Totals Balance at January 1, 2016 $ 49,267 $ 105,286 $ 49,755 $ 216,589 $ 32,208 $ — $ 453,105 Acquired from acquisitions — — 1,197 — — — 1,197 Measurement period adjustment from prior acquisitions — — — 2,095 — — 2,095 Foreign currency translation and other (579 ) 1,319 157 2,140 2,057 — 5,094 Balance at June 30, 2016 $ 48,688 $ 106,605 $ 51,109 $ 220,824 $ 34,265 $ — $ 461,491 The Company assesses goodwill for impairment on an annual basis as of December 31, or at an interim date when events or changes in the business environment would more likely than not reduce the fair value of a reporting unit below its carrying value. The Company conducted the annual impairment test of goodwill for all reporting units as of December 31, 2015 and determined that no adjustment to the carrying value of goodwill for any reporting units was necessary because the fair value of each of the reporting units exceeded that reporting unit's respective carrying value. The Company's next annual impairment assessment will be performed as of December 31, 2016 unless indicators arise that would require the Company to re-evaluate at an earlier date. As of June 30, 2016 and December 31, 2015 , the Company's finite-lived and indefinite-lived intangible assets consisted of the following (in thousands): June 30, 2016 December 31, 2015 Cost Accumulated Net Weighted Cost Accumulated Net Weighted Permits $ 162,611 $ 64,533 $ 98,078 20.7 $ 161,396 $ 61,142 $ 100,254 19.0 Customer and supplier relationships 379,236 115,500 263,736 9.5 374,866 99,463 275,403 10.1 Other intangible assets 33,984 26,517 7,467 1.2 31,416 22,581 8,835 1.5 Total amortizable permits and other intangible assets 575,831 206,550 369,281 9.3 567,678 183,186 384,492 10.0 Trademarks and trade names 122,943 — 122,943 Indefinite 122,326 — 122,326 Indefinite Total permits and other intangible assets $ 698,774 $ 206,550 $ 492,224 $ 690,004 $ 183,186 $ 506,818 Amortization expense of permits and other intangible assets was $9.9 million and $19.5 million for the three and six months ended June 30, 2016 , respectively. Amortization expense of permits and other intangible assets was $8.8 million and $19.8 million for the three and six months ended June 30, 2015 , respectively. The expected amortization of the net carrying amount of finite-lived intangible assets at June 30, 2016 was as follows (in thousands): Years Ending December 31, Expected Amortization 2016 (six months) $ 19,941 2017 35,033 2018 31,795 2019 28,897 2020 26,277 Thereafter 227,338 $ 369,281

ACCRUED EXPENSES

ACCRUED EXPENSES	6 Months Ended
	Jun. 30, 2016
Payables and Accruals [Abstract]
ACCRUED EXPENSES	ACCRUED EXPENSES Accrued expenses consisted of the following at June 30, 2016 and December 31, 2015 (in thousands): June 30, 2016 December 31, 2015 Insurance $ 57,273 $ 55,899 Interest 21,587 20,500 Accrued compensation and benefits 50,275 35,646 Income, real estate, sales and other taxes 39,623 37,095 Other 35,055 44,520 $ 203,813 $ 193,660

CLOSURE AND POST-CLOSURE LIABIL

CLOSURE AND POST-CLOSURE LIABILITIES	6 Months Ended
	Jun. 30, 2016
Asset Retirement Obligation Disclosure [Abstract]
CLOSURE AND POST-CLOSURE LIABILITIES	CLOSURE AND POST-CLOSURE LIABILITIES The changes to closure and post-closure liabilities (also referred to as “asset retirement obligations”) from January 1, 2016 through June 30, 2016 were as follows (in thousands): Landfill Non-Landfill Total Balance at January 1, 2016 $ 32,023 $ 24,226 $ 56,249 Adjustments during the measurement period related to acquisitions — 657 657 New asset retirement obligations 1,263 — 1,263 Accretion 1,384 1,150 2,534 Changes in estimates recorded to statement of operations (597 ) (91 ) (688 ) Expenditures (475 ) (570 ) (1,045 ) Currency translation and other 152 64 216 Balance at June 30, 2016 $ 33,750 $ 25,436 $ 59,186 All of the landfill facilities included in the above were active as of June 30, 2016 . There were no significant charges (benefits) in 2016 resulting from changes in estimates for closure and post-closure liabilities. New asset retirement obligations incurred during the first six months of 2016 were discounted at the credit-adjusted risk-free rate of 6.23% .

REMEDIAL LIABILITIES

REMEDIAL LIABILITIES	6 Months Ended
	Jun. 30, 2016
Environmental Remediation Obligations [Abstract]
REMEDIAL LIABILITIES	REMEDIAL LIABILITIES The changes to remedial liabilities for the six months ended June 30, 2016 were as follows (in thousands): Remedial Liabilities for Landfill Sites Remedial Liabilities for Inactive Sites Remedial Liabilities (Including Superfund) for Non-Landfill Operations Total Balance at January 1, 2016 $ 2,327 $ 63,613 $ 66,052 $ 131,992 Accretion 54 1,364 1,101 2,519 Changes in estimates recorded to statement of operations 70 (116 ) 419 373 Expenditures (61 ) (2,092 ) (3,256 ) (5,409 ) Currency translation and other — 52 764 816 Balance at June 30, 2016 $ 2,390 $ 62,821 $ 65,080 $ 130,291 In the six months ended June 30, 2016 there were no significant charges (benefits) resulting from changes in estimates for remedial liabilities.

FINANCING ARRANGEMENTS

FINANCING ARRANGEMENTS	6 Months Ended
	Jun. 30, 2016
Debt Disclosure [Abstract]
FINANCING ARRANGEMENTS	FINANCING ARRANGEMENTS The following table is a summary of the Company’s financing arrangements (in thousands): June 30, 2016 December 31, 2015 Senior unsecured notes, at 5.25%, due August 1, 2020 ("2020 Notes") $ 800,000 $ 800,000 Senior unsecured notes, at 5.125%, due June 1, 2021 ("2021 Notes") 845,000 595,000 Long-term obligations, at par $ 1,645,000 $ 1,395,000 Unamortized debt issuance costs and premium, net (13,119 ) (12,457 ) Long-term obligations, at carrying value $ 1,631,881 $ 1,382,543 At June 30, 2016 and December 31, 2015 , the fair value of the Company's 2020 Notes was $819.0 million and $812.0 million , respectively, based on quoted market prices for the instrument. The fair value of the 2020 Notes is considered a Level 2 measure according to the fair value hierarchy. On March 14, 2016, the Company issued through a private placement $ 250.0 million aggregate principal amount as additional notes under the indenture pursuant to which the Company previously issued on December 7, 2012, through a private placement $ 600.0 million aggregate principal amount of 2021 Notes. Interest payments are paid semi-annually on June 1 and December 1 of each year. At June 30, 2016 and December 31, 2015 , the fair value of the Company's 2021 Notes was $859.8 million and $599.5 million , respectively, based on quoted market prices for the instrument. The fair value of the 2021 Notes is considered a Level 2 measure according to the fair value hierarchy. The Company also maintains a revolving credit facility which as of June 30, 2016 and December 31, 2015 had no outstanding loan balances. At June 30, 2016 , $190.0 million was available to borrow and outstanding letters of credit were $140.5 million . At December 31, 2015 , $178.5 million was available to borrow and outstanding letters of credit were $144.6 million . The revolving credit facility is guaranteed by all of Clean Harbors, Inc.'s ("Parent's") domestic subsidiaries and secured by substantially all of the Parent’s and its domestic subsidiaries’ assets. Available credit for Parent and its domestic subsidiaries is limited to 85% of their eligible accounts receivable and 100% of their cash deposited in a controlled account with the agent. Available credit for Parent’s Canadian subsidiaries is limited to 85% of their eligible accounts receivable and 100% of their cash deposited in a controlled account with the agent’s Canadian affiliate. The obligations of the Canadian subsidiaries under the revolving credit facility are guaranteed by all of Parent’s Canadian subsidiaries and secured by the accounts receivable of the Canadian subsidiaries, but the Canadian subsidiaries do not guarantee and are not otherwise responsible for the obligations of Parent or its domestic subsidiaries.

EARNINGS (LOSS) PER SHARE

EARNINGS (LOSS) PER SHARE	6 Months Ended
	Jun. 30, 2016
Earnings Per Share [Abstract]
EARNINGS (LOSS) PER SHARE	EARNINGS (LOSS) PER SHARE The following are computations of basic and diluted loss per share (in thousands except for per share amounts): Three Months Ended Six Months Ended June 30, June 30, 2016 2015 2016 2015 Numerator for basic and diluted earnings per share: Net income (loss) $ 3,966 $ 10,395 $ (16,905 ) $ 3,306 Denominator: Basic shares outstanding 57,549 58,590 57,599 58,732 Dilutive effect of equity-based compensation awards 129 120 — 100 Dilutive shares outstanding 57,678 58,710 57,599 58,832 Basic earnings (loss) per share: $ 0.07 $ 0.18 $ (0.29 ) $ 0.06 Diluted earnings (loss) per share: $ 0.07 $ 0.18 $ (0.29 ) $ 0.06 For the three months ended June 30, 2016 and 2015 , the dilutive effect of all then outstanding options, restricted stock and performance awards is included in the EPS calculations above except for 348,197 and 196,180 , respectively, of outstanding performance stock awards for which the performance criteria were not attained at that time and 9,537 and 11,075 , respectively, of restricted stock awards which were antidilutive at that time. As a result of the net loss reported for the six months ended June 30, 2016 , all then outstanding stock options, restricted stock awards and performance awards totaling 886,685 were excluded from the calculation of diluted earnings (loss) per share as their inclusion would have an antidilutive effect. For the six months ended June 30, 2015 , the dilutive effect of all then outstanding options, restricted stock and performance awards is included in the EPS calculations above except for 196,180 of outstanding performance stock awards for which the performance criteria were not attained at that time and 38,171 of restricted stock awards which were antidilutive at that time.

ACCUMULATED OTHER COMPREHENSIVE

ACCUMULATED OTHER COMPREHENSIVE LOSS	6 Months Ended
	Jun. 30, 2016
Equity [Abstract]
ACCUMULATED OTHER COMPREHENSIVE LOSS	ACCUMULATED OTHER COMPREHENSIVE LOSS The changes in accumulated other comprehensive loss by component and related tax effects for the six months ended June 30, 2016 were as follows (in thousands): Foreign Currency Translation Unfunded Pension Liability Total Balance at January 1, 2016 $ (252,939 ) $ (1,953 ) $ (254,892 ) Other comprehensive income before reclassifications 44,659 — 44,659 Other comprehensive income $ 44,659 $ — $ 44,659 Balance at June 30, 2016 $ (208,280 ) $ (1,953 ) $ (210,233 ) There were no reclassifications out of accumulated other comprehensive loss during the three and six months ended June 30, 2016 and 2015 .

STOCK-BASED COMPENSATION

STOCK-BASED COMPENSATION	6 Months Ended
	Jun. 30, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
STOCK-BASED COMPENSATION	STOCK-BASED COMPENSATION Total stock-based compensation cost charged to selling, general and administrative expenses for the three and six months ended June 30, 2016 was $2.6 million and $4.7 million , respectively. Total stock-based compensation cost charged to selling, general and administrative expenses for the three and six months ended June 30, 2015 was $4.3 million and $6.1 million , respectively. The total income tax benefit recognized in the consolidated statements of operations from stock-based compensation was $0.8 million and $1.4 million for the three and six months ended June 30, 2016 , respectively. The total income tax benefit recognized in the consolidated statements of operations from stock-based compensation was $0.6 million and $1.1 million for the three and six months ended June 30, 2015 , respectively. Restricted Stock Awards The following information relates to restricted stock awards that have been granted to employees and directors under the Company's equity incentive plans (the "Plans"). The restricted stock awards are not transferable until vested and the restrictions generally lapse upon the achievement of continued employment over a three -to- five -year period or service as a director until the following annual meeting of shareholders. The fair value of each restricted stock grant is based on the closing price of the Company's common stock on the date of grant and is amortized to expense over its vesting period. The following table summarizes information about restricted stock awards for the six months ended June 30, 2016 : Restricted Stock Number of Shares Weighted Average Grant-Date Fair Value Balance at January 1, 2016 362,618 $ 55.79 Granted 299,967 $ 51.02 Vested (128,895 ) $ 55.18 Forfeited (16,785 ) $ 57.22 Balance at June 30, 2016 516,905 $ 53.12 As of June 30, 2016 , there was $23.2 million of total unrecognized compensation cost arising from restricted stock awards under the Company's Plans. This cost is expected to be recognized over a weighted average period of 3.1 years. The total fair value of restricted stock vested during the three and six months ended June 30, 2016 was $2.3 million and $6.1 million , respectively. The total fair value of restricted stock vested during the three and six months ended June 30, 2015 was $3.0 million and $6.2 million , respectively. Performance Stock Awards The following information relates to performance stock awards that have been granted to employees under the Company's Plans. Performance stock awards are subject to performance criteria established by the compensation committee of the Company's board of directors prior to or at the date of grant. The vesting of the performance stock awards is based on achieving such targets typically based on revenue, Adjusted EBITDA margin, return on invested capital percentage and Total Recordable Incident Rate. In addition, performance stock awards include continued service conditions. The fair value of each performance stock award is based on the closing price of the Company's common stock on the date of grant and is amortized to expense over the service period if achievement of performance measures is considered probable. The following table summarizes information about performance stock awards for the six months ended June 30, 2016 : Performance Stock Number of Shares Weighted Average Grant-Date Fair Value Balance at January 1, 2016 187,274 $ 57.13 Granted 204,602 $ 54.30 Vested (8,420 ) $ 61.90 Forfeited (13,676 ) $ 57.23 Balance at June 30, 2016 369,780 $ 55.45 As of June 30, 2016 , there was $0.6 million of total unrecognized compensation cost arising from unvested performance stock awards deemed probable of vesting under the Company's Plans. No performance awards vested during the three months ended June 30, 2016 . The total fair value of performance awards vested during the six months ended June 30, 2016 was $0.4 million . The total fair value of performance awards vested during the six months ended June 30, 2015 was $0.3 million . No performance awards vested during the three months ended June 30, 2015 . Common Stock Repurchases On March 13, 2015, the Company's board of directors authorized the repurchase of up to $300 million of the Company's common stock. During the three and six months ended June 30, 2016 , the Company repurchased and retired a total of 0.1 million shares and 0.2 million shares, respectively, of the Company's common stock for a total cost of $5.1 million and $10.1 million , respectively. During the three and six months ended June 30, 2015, the Company repurchased and retired a total of 0.3 million shares and 0.6 million shares, respectively, of the Company's common stock for a total cost of $16.1 million and $32.2 million , respectively. Through June 30, 2016 , the Company has repurchased and retired a total of 3.6 million shares of the Company's common stock for a total cost of $187.8 million under this program. As of June 30, 2016 , an additional $112.2 million remains available for repurchase of shares under the current authorized program.

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	6 Months Ended
	Jun. 30, 2016
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES Legal and Administrative Proceedings The Company and its subsidiaries are subject to legal proceedings and claims arising in the ordinary course of business. Actions filed against the Company arise from commercial and employment-related claims including alleged class actions related to sales practices and wage and hour claims. The plaintiffs in these actions may be seeking damages or injunctive relief or both. These actions are in various jurisdictions and stages of proceedings, and some are covered in part by insurance. In addition, the Company’s waste management services operations are regulated by federal, state, provincial and local laws enacted to regulate discharge of materials into the environment, remediation of contaminated soil and groundwater or otherwise protect the environment. This ongoing regulation results in the Company frequently becoming a party to legal or administrative proceedings involving all levels of governmental authorities and other interested parties. The issues involved in such proceedings generally relate to alleged violations of existing permits and licenses or alleged responsibility under federal or state Superfund laws to remediate contamination at properties owned either by the Company or by other parties (“third party sites”) to which either the Company or the prior owners of certain of the Company’s facilities shipped wastes. At June 30, 2016 and December 31, 2015 , the Company had recorded reserves of $21.1 million and $21.9 million , respectively, in the Company's financial statements for actual or probable liabilities related to the legal and administrative proceedings in which the Company was then involved, the principal of which are described below. At June 30, 2016 and December 31, 2015 , the Company also believed that it was reasonably possible that the amount of these potential liabilities could be as much as $1.8 million and $1.9 million more, respectively. The Company periodically adjusts the aggregate amount of these reserves when actual or probable liabilities are paid or otherwise discharged, new claims arise, or additional relevant information about existing or probable claims becomes available. As of June 30, 2016 and December 31, 2015 , the $21.1 million and $21.9 million , respectively, of reserves consisted of (i) $18.7 million and $18.9 million , respectively, related to pending legal or administrative proceedings, including Superfund liabilities, which were included in remedial liabilities on the consolidated balance sheets, and (ii) $2.4 million and $3.0 million , respectively, primarily related to federal, state and provincial enforcement actions, which were included in accrued expenses on the consolidated balance sheets. As of June 30, 2016 , the principal legal and administrative proceedings in which the Company was involved, or which had been terminated during 2016 , were as follows: Ville Mercier. In September 2002, the Company acquired the stock of a subsidiary (the "Mercier Subsidiary") which owns a hazardous waste incinerator in Ville Mercier, Quebec (the "Mercier Facility"). The property adjacent to the Mercier Facility, which is also owned by the Mercier Subsidiary, is now contaminated as a result of actions dating back to 1968, when the Government of Quebec issued to a company unrelated to the Mercier Subsidiary two permits to dump organic liquids into lagoons on the property. In 1999, Ville Mercier and three neighboring municipalities filed separate legal proceedings against the Mercier Subsidiary and the Government of Quebec. In 2012, the municipalities amended their existing statement of claim to seek $2.9 million (Cdn) in general damages and $10.0 million (Cdn) in punitive damages, plus interest and costs, as well as injunctive relief. Both the Government of Quebec and the Company have filed summary judgment motions against the municipalities. The parties are currently attempting to negotiate a resolution and hearings on the motions have been delayed. In September 2007, the Quebec Minister of Sustainable Development, Environment and Parks issued a Notice pursuant to Section 115.1 of the Environment Quality Act, superseding Notices issued in 1992, which are the subject of the pending litigation. The more recent Notice notifies the Mercier Subsidiary that, if the Mercier Subsidiary does not take certain remedial measures at the site, the Minister intends to undertake those measures at the site and claim direct and indirect costs related to such measures. The Company has accrued for costs expected to be incurred relative to the resolution of this matter and believes this matter will not have a future material effect on its financial position or results of operations. Safety-Kleen Legal Proceedings. On December 28, 2012, the Company acquired Safety-Kleen, Inc. ("Safety-Kleen") and thereby became subject to the legal proceedings in which Safety-Kleen was a party on that date. In addition to certain Superfund proceedings in which Safety-Kleen has been named as a potentially responsible party as described below under “Superfund Proceedings,” the principal such legal proceedings involving Safety-Kleen which were outstanding as of June 30, 2016 were as follows: Product Liability Cases. Safety-Kleen has been named as a defendant in various lawsuits that are currently pending in various courts and jurisdictions throughout the United States, including approximately 62 proceedings (excluding cases which have been settled but not formally dismissed) as of June 30, 2016 , wherein persons claim personal injury resulting from the use of Safety-Kleen's parts cleaning equipment or cleaning products. These proceedings typically involve allegations that the solvent used in Safety-Kleen's parts cleaning equipment contains contaminants and/or that Safety-Kleen's recycling process does not effectively remove the contaminants that become entrained in the solvent during their use. In addition, certain claimants assert that Safety-Kleen failed to warn adequately the product user of potential risks, including an historic failure to warn that solvent contains trace amounts of toxic or hazardous substances such as benzene. Safety-Kleen maintains insurance that it believes will provide coverage for these product liability claims (over amounts accrued for self-insured retentions and deductibles in certain limited cases), except for punitive damages to the extent not insurable under state law or excluded from insurance coverage. Safety-Kleen also believes that these claims lack merit and has historically vigorously defended, and intends to continue to vigorously defend, itself and the safety of its products against all of these claims. Such matters are subject to many uncertainties and outcomes are not predictable with assurance. Consequently, Safety-Kleen is unable to ascertain the ultimate aggregate amount of monetary liability or financial impact with respect to these matters as of June 30, 2016 . From January 1, 2016 to June 30, 2016 , 14 product liability claims were settled or dismissed. Due to the nature of these claims and the related insurance, the Company did not incur any expense as Safety-Kleen's insurance provided coverage in full for all such claims. Safety-Kleen may be named in similar, additional lawsuits in the future, including claims for which insurance coverage may not be available. Superfund Proceedings The Company has been notified that either the Company (which, since December 28, 2012, includes Safety-Kleen) or the prior owners of certain of the Company's facilities for which the Company may have certain indemnification obligations have been identified as potentially responsible parties ("PRPs") or potential PRPs in connection with 129 sites which are subject to or are proposed to become subject to proceedings under federal or state Superfund laws. Of the 129 sites, two (the Wichita Facility and the BR Facility described below) involve facilities that are now owned by the Company and 127 involve third party sites to which either the Company or the prior owners of certain of the Company’s facilities shipped wastes. Of the 127 third party sites, 32 are now settled, 15 are currently requiring expenditures on remediation and 80 are not currently requiring expenditures on remediation. In connection with each site, the Company has estimated the extent, if any, to which it may be subject, either directly or as a result of any indemnification obligations, for cleanup and remediation costs, related legal and consulting costs associated with PRP investigations, settlements, and related legal and administrative proceedings. The amount of such actual and potential liability is inherently difficult to estimate because of, among other relevant factors, uncertainties as to the legal liability (if any) of the Company or the prior owners of certain of the Company's facilities to contribute a portion of the cleanup costs, the assumptions that must be made in calculating the estimated cost and timing of remediation, the identification of other PRPs and their respective capability and obligation to contribute to remediation efforts, and the existence and legal standing of indemnification agreements (if any) with prior owners, which may either benefit the Company or subject the Company to potential indemnification obligations. In addition to the Wichita Property and the BR Facility described below, Clean Harbors believes its potential liability could exceed $100,000 at 11 of the 127 third party sites. Wichita Property. The Company acquired in 2002 as part of the CSD assets a service center located in Wichita, Kansas (the "Wichita Property"). The Wichita Property is one of several properties located within the boundaries of a 1,400 acre state-designated Superfund site in an old industrial section of Wichita known as the North Industrial Corridor Site. Along with numerous other PRPs, the former owner executed a consent decree relating to such site with the U.S. Environmental Protection Agency (the "EPA"), and the Company is continuing an ongoing remediation program for the Wichita Property in accordance with that consent decree. The Company also acquired rights under an indemnification agreement between the former owner and an earlier owner of the Wichita Property. The Company filed suit against the earlier owner in July of 2015 to recover costs incurred during the cleanup of the property. BR Facility. The Company acquired in 2002 a former hazardous waste incinerator and landfill in Baton Rouge (the "BR Facility"), for which operations had been previously discontinued by the prior owner. In September 2007, the EPA issued a special notice letter to the Company related to the Devil's Swamp Lake Site ("Devil's Swamp") in East Baton Rouge Parish, Louisiana. Devil's Swamp includes a lake located downstream of an outfall ditch where wastewater and stormwater have been discharged, and Devil's Swamp is proposed to be included on the National Priorities List due to the presence of Contaminants of Concern ("COC") cited by the EPA. These COCs include substances of the kind found in wastewater and storm water discharged from the BR Facility in past operations. The EPA originally requested COC generators to submit a good faith offer to conduct a remedial investigation feasibility study directed towards the eventual remediation of the site. The Company is currently performing corrective actions at the BR Facility under an order issued by the Louisiana Department of Environmental Quality, and has begun conducting the remedial investigation and feasibility study under an order issued by the EPA. The Company cannot presently estimate the potential additional liability for the Devil's Swamp cleanup until a final remedy is selected by the EPA. Third Party Sites. Of the 127 third party sites at which the Company has been notified it is a PRP or potential PRP or may have indemnification obligations, Clean Harbors has an indemnification agreement at 11 of these sites with ChemWaste, a former subsidiary of Waste Management, Inc., and at six additional of these third party sites, Safety-Kleen has a similar indemnification agreement with McKesson Corporation. These agreements indemnify the Company (which now includes Safety-Kleen) with respect to any liability at the 17 sites for waste disposed prior to the Company's (or Safety-Kleen's) acquisition of the former subsidiaries of Waste Management or McKesson which had shipped wastes to those sites. Accordingly, Waste Management or McKesson are paying all costs of defending those subsidiaries in those 17 cases, including legal fees and settlement costs. However, there can be no guarantee that the Company's ultimate liabilities for those sites will not exceed the amount recorded or that indemnities applicable to any of these sites will be available to pay all or a portion of related costs. Except for the indemnification agreements which the Company holds from ChemWaste and McKesson, the Company does not have an indemnity agreement with respect to any of the 127 third party sites discussed above. Federal, State and Provincial Enforcement Actions From time to time, the Company pays fines or penalties in regulatory proceedings relating primarily to waste treatment, storage or disposal facilities. As of June 30, 2016 and December 31, 2015 , there were four and six proceedings, respectively, for which the Company reasonably believed that the sanctions could equal or exceed $100,000 . The Company believes that the fines or other penalties in these or any of the other regulatory proceedings will, individually or in the aggregate, not have a material effect on its financial condition, results of operations or cash flows.

INCOME TAXES

INCOME TAXES	6 Months Ended
	Jun. 30, 2016
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXES The Company records a tax provision or benefit on an interim basis using an estimated annual effective tax rate. This rate is applied to the current period ordinary income or loss to determine the income tax provision or benefit allocated to the interim period. Losses from jurisdictions for which no benefit can be recognized and the income tax effects of unusual or infrequent items are excluded from the estimated annual effective tax rate and are recognized in the impacted interim period. The estimated annual effective tax rate may be significantly impacted by projected earnings mix by tax jurisdiction. Adjustments to the estimated annual effective income tax rate are recognized in the period when such estimates are revised. The Company's effective tax rate for the three and six months ended June 30, 2016 was 68.7% and (57.3)% compared to 74.6% and 88.6% for the same periods in 2015. The variations in the effective income tax rates for the three and six months ended June 30, 2016 as compared to more customary relationships between pre-tax income and the provision for income taxes was primarily due to not recognizing income tax benefits from current operating losses related to certain Canadian entities. Such variations in the three and six month periods ended June 30, 2015 were due to the lack of any tax benefit associated with the goodwill impairment charge recorded in the second quarter of 2015. As of June 30, 2016 and December 31, 2015 , the Company had recorded $2.1 million of liabilities for unrecognized tax benefits and $0.4 million of interest, respectively. Due to expiring statute of limitation periods, the Company believes that total unrecognized tax benefits will decrease by approximately $0.5 million within the next 12 months. This is the result of a pre-acquisition audit settlement for one of the Company's foreign entities.

SEGMENT REPORTING

SEGMENT REPORTING	6 Months Ended
	Jun. 30, 2016
Segment Reporting [Abstract]
SEGMENT REPORTING	SEGMENT REPORTING Segment reporting is prepared on the same basis that the Company's chief executive officer, who is the Company's chief operating decision maker, manages the business, makes operating decisions and assesses performance. As of June 30, 2016 , the Company's operations were managed in six reportable segments based primarily upon the nature of the various operations and services provided: Technical Services, Industrial and Field Services which consists of the Industrial Services and Field Services operating segments, Kleen Performance Products, SK Environmental Services, Lodging Services and Oil and Gas Field Services. Third party revenue is revenue billed to outside customers by a particular segment. Direct revenue is revenue allocated to the segment providing the product or service. Intersegment revenues represent the sharing of third party revenues among the segments based on products and services provided by each segment as if the products and services were sold directly to the third party. The intersegment revenues are shown net. The negative intersegment revenues are due to more transfers out of customer revenues to other segments than transfers in of customer revenues from other segments. The operations not managed through the Company’s six reportable segments are recorded as “Corporate Items.” Corporate Items revenues consist of certain operations for which the revenues are insignificant and not allocated to the segments for internal reporting purposes. Corporate Items cost of revenues represents certain central services that are not allocated to the six segments for internal reporting purposes. Corporate Items selling, general and administrative expenses include typical corporate items such as legal, accounting and other items of a general corporate nature that are not allocated to the Company’s six reportable segments. Performance of the segments is evaluated on several factors, of which the primary financial measure is “Adjusted EBITDA,” which consists of net income (loss) plus accretion of environmental liabilities, depreciation and amortization, net interest expense, provision for income taxes, other non-cash charges not deemed representative of fundamental segment results and excludes other expense. Transactions between the segments are accounted for at the Company’s best estimate based on similar transactions with outside customers. The following table reconciles third party revenues to direct revenues for the three and six months ended June 30, 2016 and 2015 (in thousands): For the Three Months Ended June 30, 2016 For the Three Months Ended June 30, 2015 Third party revenues Intersegment revenues, net Corporate Items, net Direct revenues Third party revenues Intersegment revenues, net Corporate Items, net Direct revenues Technical Services $ 229,130 $ 35,578 $ 667 $ 265,375 $ 248,025 $ 38,314 $ 1,083 $ 287,422 Industrial and Field Services 153,851 (9,055 ) (286 ) 144,510 353,329 (11,230 ) (401 ) 341,698 Kleen Performance Products 86,711 (7,600 ) — 79,111 99,104 (21,428 ) (1 ) 77,675 SK Environmental Services 191,004 (21,492 ) 1 169,513 175,876 (8,802 ) 3 167,077 Lodging Services 16,418 137 14 16,569 21,171 992 80 22,243 Oil and Gas Field Services 19,232 2,432 48 21,712 38,617 2,154 40 40,811 Corporate Items 1,164 — (444 ) 720 106 — (804 ) (698 ) Total $ 697,510 $ — $ — $ 697,510 $ 936,228 $ — $ — $ 936,228 For the Six Months Ended June 30, 2016 For the Six Months Ended June 30, 2015 Third party revenues Intersegment revenues, net Corporate Items, net Direct revenues Third party revenues Intersegment revenues, net Corporate Items, net Direct revenues Technical Services $ 448,235 $ 70,422 $ 1,055 $ 519,712 $ 488,350 $ 73,218 $ 2,380 $ 563,948 Industrial and Field Services 275,428 (16,521 ) (303 ) 258,604 500,197 (17,791 ) (323 ) 482,083 Kleen Performance Products 154,254 (17,007 ) (1 ) 137,246 195,911 (39,685 ) (2 ) 156,224 SK Environmental Services 370,422 (40,606 ) 368 330,184 336,560 (20,384 ) 3 316,179 Lodging Services 32,063 401 35 32,499 55,275 1,156 97 56,528 Oil and Gas Field Services 51,248 3,311 135 54,694 92,204 3,486 49 95,739 Corporate Items 1,943 — (1,289 ) 654 230 — (2,204 ) (1,974 ) Total $ 1,333,593 $ — $ — $ 1,333,593 $ 1,668,727 $ — $ — $ 1,668,727 The following table presents Adjusted EBITDA information used by management by reported segment (in thousands). The Company does not allocate interest expense, income taxes, depreciation, amortization, accretion of environmental liabilities, other non-cash charges not deemed representative of fundamental segment results, and other expense (income) to its segments. For the Three Months Ended For the Six Months Ended June 30, June 30, 2016 2015 2016 2015 Adjusted EBITDA: Technical Services $ 68,891 $ 76,808 $ 129,289 $ 140,209 Industrial and Field Services 19,946 73,081 22,064 83,390 Kleen Performance Products 9,995 15,824 14,555 11,348 SK Environmental Services 45,239 41,195 80,734 68,444 Lodging Services 3,022 3,852 4,041 10,762 Oil and Gas Field Services (4,207 ) (2,182 ) (5,601 ) (779 ) Corporate Items (32,441 ) (45,456 ) (67,317 ) (71,975 ) Total $ 110,445 $ 163,122 $ 177,765 $ 241,399 Reconciliation to Consolidated Statements of Operations: Accretion of environmental liabilities 2,548 2,599 5,053 5,218 Depreciation and amortization 73,393 67,773 142,295 136,129 Goodwill impairment charge — 31,992 — 31,992 Income from operations 34,504 60,758 30,417 68,060 Other expense 189 660 539 251 Interest expense, net of interest income 21,647 19,249 40,627 38,687 Income (loss) before provision for income taxes $ 12,668 $ 40,849 $ (10,749 ) $ 29,122 The following table presents certain assets by reportable segment and in the aggregate (in thousands): June 30, 2016 Technical Industrial and Field Kleen Performance Products SK Environmental Services Lodging Services Oil and Gas Field Corporate Totals Property, plant and equipment, net $ 507,996 $ 231,334 $ 211,082 $ 302,260 $ 104,386 $ 146,423 $ 91,506 $ 1,594,987 Goodwill 48,688 106,605 51,109 220,824 34,265 — — 461,491 Permits and other intangibles, net 69,683 13,587 139,867 251,087 6,495 11,505 — 492,224 Total assets $ 823,881 $ 375,796 $ 520,943 $ 852,082 $ 181,031 $ 235,775 $ 702,873 $ 3,692,381 December 31, 2015 Technical Industrial and Field Kleen Performance Products SK Environmental Services Lodging Services Oil and Gas Field Corporate Totals Property, plant and equipment, net $ 483,425 $ 237,660 $ 193,855 $ 264,539 $ 105,208 $ 156,286 $ 91,494 $ 1,532,467 Goodwill 49,267 105,286 49,755 216,589 32,208 — — 453,105 Permits and other intangibles, net 73,601 14,649 140,410 256,251 7,045 14,862 — 506,818 Total assets $ 800,060 $ 368,858 $ 492,483 $ 805,488 $ 181,357 $ 244,210 $ 538,972 $ 3,431,428 The following table presents total assets by geographical area (in thousands): June 30, 2016 December 31, 2015 United States $ 2,837,201 $ 2,575,746 Canada 850,355 851,949 Other foreign 4,825 3,733 Total $ 3,692,381 $ 3,431,428

GUARANTOR AND NON-GUARANTOR SUB

GUARANTOR AND NON-GUARANTOR SUBSIDIARIES FINANCIAL INFORMATION	6 Months Ended
	Jun. 30, 2016
Guarantor and Non-Guarantor Subsidiaries Financial Information [Abstract]
GUARANTOR AND NON-GUARANTOR SUBSIDIARIES FINANCIAL INFORMATION	GUARANTOR AND NON-GUARANTOR SUBSIDIARIES FINANCIAL INFORMATION The 2020 Notes and the 2021 Notes are guaranteed by substantially all of the Company's subsidiaries organized in the United States (the "U.S. Guarantor Subsidiaries"). Each U.S. Guarantor Subsidiary is a 100% owned subsidiary of Clean Harbors, Inc. ("Parent") and its guarantee is both full and unconditional and joint and several. The guarantees, are however, subject to customary release provisions under which, in particular, the guarantee of any U.S. Guarantor Subsidiary will be released if we sell such subsidiary to an unrelated third party in accordance with the terms of the indenture which governs the notes. The 2020 Notes and the 2021 Notes are not guaranteed by Parent's Canadian or other foreign subsidiaries (the "Foreign Non-Guarantor Subsidiaries"). The following presents supplemental condensed consolidating financial information for Parent, the U.S. Guarantor Subsidiaries and the Foreign Non-Guarantor Subsidiaries, respectively. As discussed further in Note 10, “Financing Arrangements,” to our consolidated financial statements included herein, on March 14, 2016, Parent issued through a private placement, $ 250.0 million aggregate principal amount as additional notes under the 2021 Notes. In connection with this offering the proceeds were then transferred to the US Guarantor Subsidiaries and are reflected as an investment of Parent in the U.S. Guarantor Subsidiaries for the period ending June 30, 2016. Following is the condensed consolidating balance sheet at June 30, 2016 (in thousands): Clean Harbors, Inc. U.S. Guarantor Subsidiaries Foreign Non-Guarantor Subsidiaries Consolidating Adjustments Total Assets: Cash and cash equivalents $ 51,291 $ 224,493 $ 77,139 $ — $ 352,923 Intercompany receivables 181,741 302,354 30,741 (514,836 ) — Accounts receivable, net — 407,601 96,148 — 503,749 Other current assets 378 198,612 63,472 — 262,462 Property, plant and equipment, net — 1,138,285 456,702 — 1,594,987 Investments in subsidiaries 2,833,394 514,708 — (3,348,102 ) — Intercompany debt receivable — 277,623 3,701 (281,324 ) — Goodwill — 369,978 91,513 — 461,491 Permits and other intangibles, net — 423,932 68,292 — 492,224 Other long-term assets 1,412 9,559 13,574 — 24,545 Total assets $ 3,068,216 $ 3,867,145 $ 901,282 $ (4,144,262 ) $ 3,692,381 Liabilities and Stockholders’ Equity: Current liabilities $ 21,852 $ 427,367 $ 71,202 $ — $ 520,421 Intercompany payables 294,439 217,430 2,967 (514,836 ) — Closure, post-closure and remedial liabilities, net — 150,182 15,252 — 165,434 Long-term obligations 1,631,881 — — — 1,631,881 Intercompany debt payable 3,701 — 277,623 (281,324 ) — Other long-term liabilities — 238,772 19,530 — 258,302 Total liabilities 1,951,873 1,033,751 386,574 (796,160 ) 2,576,038 Stockholders’ equity 1,116,343 2,833,394 514,708 (3,348,102 ) 1,116,343 Total liabilities and stockholders’ equity $ 3,068,216 $ 3,867,145 $ 901,282 $ (4,144,262 ) $ 3,692,381 Following is the condensed consolidating balance sheet at December 31, 2015 (in thousands): Clean Harbors, Inc. U.S. Guarantor Subsidiaries Foreign Non-Guarantor Subsidiaries Consolidating Adjustments Total Assets: Cash and cash equivalents $ 11,017 $ 83,479 $ 90,212 $ — $ 184,708 Intercompany receivables 164,709 213,243 39,804 (417,756 ) — Accounts receivables, net — 404,580 91,424 — 496,004 Other current assets — 179,969 60,515 — 240,484 Property, plant and equipment, net — 1,082,466 450,001 — 1,532,467 Investments in subsidiaries 2,547,307 522,067 — (3,069,374 ) — Intercompany debt receivable — 260,957 3,701 (264,658 ) — Goodwill — 367,306 85,799 — 453,105 Permits and other intangibles, net — 435,080 71,738 — 506,818 Other long-term assets 1,068 10,274 6,500 — 17,842 Total assets $ 2,724,101 $ 3,559,421 $ 899,694 $ (3,751,788 ) $ 3,431,428 Liabilities and Stockholders’ Equity: Current liabilities $ 20,813 $ 424,588 $ 71,719 $ — $ 517,120 Intercompany payables 220,762 195,287 1,707 (417,756 ) — Closure, post-closure and remedial liabilities, net — 153,190 14,656 — 167,846 Long-term obligations 1,382,543 — — — 1,382,543 Intercompany debt payable 3,701 — 260,957 (264,658 ) — Other long-term liabilities — 239,049 28,588 — 267,637 Total liabilities 1,627,819 1,012,114 377,627 (682,414 ) 2,335,146 Stockholders’ equity 1,096,282 2,547,307 522,067 (3,069,374 ) 1,096,282 Total liabilities and stockholders’ equity $ 2,724,101 $ 3,559,421 $ 899,694 $ (3,751,788 ) $ 3,431,428 Following is the consolidating statement of operations for the three months ended June 30, 2016 (in thousands): Clean Harbors, Inc. U.S. Guarantor Subsidiaries Foreign Non-Guarantor Subsidiaries Consolidating Adjustments Total Revenues Service revenues $ — $ 456,013 $ 139,413 $ (10,864 ) $ 584,562 Product revenues — 95,648 19,391 (2,091 ) 112,948 Total revenues — 551,661 158,804 (12,955 ) 697,510 Cost of revenues (exclusive of items shown separately below) Service cost of revenues (587 ) 292,343 107,792 (10,864 ) 388,684 Product cost of revenues — 79,108 14,301 (2,091 ) 91,318 Total cost of revenues (587 ) 371,451 122,093 (12,955 ) 480,002 Selling, general and administrative expenses 37 83,882 23,144 — 107,063 Accretion of environmental liabilities — 2,313 235 — 2,548 Depreciation and amortization — 50,696 22,697 — 73,393 Income (loss) from operations 550 43,319 (9,365 ) — 34,504 Other expense (income) — 400 (589 ) — (189 ) Interest (expense) income (22,962 ) 1,284 31 — (21,647 ) Equity in earnings of subsidiaries, net of taxes 17,413 (9,195 ) — (8,218 ) — Intercompany interest income (expense) — 5,497 (5,497 ) — — (Loss) income before (benefit) provision for income taxes (4,999 ) 41,305 (15,420 ) (8,218 ) 12,668 (Benefit) provision for income taxes (8,965 ) 23,892 (6,225 ) — 8,702 Net income (loss) 3,966 17,413 (9,195 ) (8,218 ) 3,966 Other comprehensive loss (1,178 ) (1,178 ) (597 ) 1,775 (1,178 ) Comprehensive income (loss) $ 2,788 $ 16,235 $ (9,792 ) $ (6,443 ) $ 2,788 Following is the consolidating statement of operations for the three months ended June 30, 2015 (in thousands): Clean Harbors, Inc. U.S. Guarantor Subsidiaries Foreign Non-Guarantor Subsidiaries Consolidating Adjustments Total Revenues Service revenues $ — $ 628,408 $ 190,657 $ (17,718 ) $ 801,347 Product revenues — 115,335 22,444 (2,898 ) 134,881 Total revenues — 743,743 213,101 (20,616 ) 936,228 Cost of revenues (exclusive of items shown separately below) Service cost of revenues — 415,111 147,477 (17,718 ) 544,870 Product cost of revenues — 98,258 12,458 (2,898 ) 107,818 Total cost of revenues — 513,369 159,935 (20,616 ) 652,688 Selling, general and administrative expenses 25 93,677 26,716 — 120,418 Accretion of environmental liabilities — 2,287 312 — 2,599 Depreciation and amortization — 44,602 23,171 — 67,773 Goodwill impairment charge — 4,164 27,828 — 31,992 (Loss) income from operations (25 ) 85,644 (24,861 ) — 60,758 Other income (expense) — 168 (828 ) — (660 ) Interest (expense) income (19,652 ) 324 79 — (19,249 ) Equity in earnings of subsidiaries, net of taxes 22,201 (29,550 ) — 7,349 — Intercompany interest income (expense) — 6,036 (6,036 ) — — Income (loss) before (benefit) provision for income taxes 2,524 62,622 (31,646 ) 7,349 40,849 (Benefit) provision for income taxes (7,871 ) 40,421 (2,096 ) — 30,454 Net income (loss) 10,395 22,201 (29,550 ) 7,349 10,395 Other comprehensive income 12,231 12,231 8,061 (20,292 ) 12,231 Comprehensive income (loss) $ 22,626 $ 34,432 $ (21,489 ) $ (12,943 ) $ 22,626 Following is the consolidating statement of operations for the six months ended June 30, 2016 (in thousands): Clean Harbors, Inc. U.S. Guarantor Subsidiaries Foreign Non-Guarantor Subsidiaries Consolidating Adjustments Total Revenues Service revenues $ — $ 884,490 $ 253,436 $ (23,133 ) $ 1,114,793 Product revenues — 185,236 38,104 (4,540 ) 218,800 Total revenues — 1,069,726 291,540 (27,673 ) 1,333,593 Cost of revenues (exclusive of items shown separately below) Service cost of revenues (587 ) 575,307 211,083 (23,133 ) 762,670 Product cost of revenues — 158,462 27,689 (4,540 ) 181,611 Total cost of revenues (587 ) 733,769 238,772 (27,673 ) 944,281 Selling, general and administrative expenses 61 164,537 46,949 — 211,547 Accretion of environmental liabilities — 4,603 450 — 5,053 Depreciation and amortization — 99,391 42,904 — 142,295 Income (loss) from operations 526 67,426 (37,535 ) — 30,417 Other income (expense) — 312 (851 ) — (539 ) Interest (expense) income (43,105 ) 2,395 83 — (40,627 ) Equity in earnings of subsidiaries, net of taxes 8,642 (35,690 ) — 27,048 — Intercompany interest income (expense) — 10,656 (10,656 ) — — (Loss) income before (benefit) provision for income taxes (33,937 ) 45,099 (48,959 ) 27,048 (10,749 ) (Benefit) provision for income taxes (17,032 ) 36,457 (13,269 ) — 6,156 Net (loss) income (16,905 ) 8,642 (35,690 ) 27,048 (16,905 ) Other comprehensive gain 44,659 44,659 28,330 (72,989 ) 44,659 Comprehensive gain (loss) $ 27,754 $ 53,301 $ (7,360 ) $ (45,941 ) $ 27,754 Following is the consolidating statement of operations for the six months ended June 30, 2015 (in thousands): Clean Harbors, Inc. U.S. Guarantor Subsidiaries Foreign Non-Guarantor Subsidiaries Consolidating Adjustments Total Revenues Service revenues $ — $ 1,046,925 $ 384,110 $ (33,358 ) $ 1,397,677 Product revenues — 231,871 45,648 (6,469 ) 271,050 Total revenues — 1,278,796 429,758 (39,827 ) 1,668,727 Cost of revenues (exclusive of items shown separately below) Service cost of revenues — 692,713 301,905 (33,358 ) 961,260 Product cost of revenues — 213,544 30,860 (6,469 ) 237,935 Total cost of revenues — 906,257 332,765 (39,827 ) 1,199,195 Selling, general and administrative expenses 50 174,661 53,422 — 228,133 Accretion of environmental liabilities — 4,593 625 — 5,218 Depreciation and amortization — 90,403 45,726 — 136,129 Goodwill impairment charge — 4,164 27,828 — 31,992 (Loss) income from operations (50 ) 98,718 (30,608 ) — 68,060 Other income (expense) — 279 (530 ) — (251 ) Interest (expense) income (39,291 ) 502 102 — (38,687 ) Equity in earnings of subsidiaries, net of taxes 26,910 (36,579 ) — 9,669 — Intercompany interest income (expense) — 12,013 (12,013 ) — — (Loss) income before (benefit) provision for income taxes (12,431 ) 74,933 (43,049 ) 9,669 29,122 (Benefit) provision for income taxes (15,737 ) 48,023 (6,470 ) — 25,816 Net income (loss) 3,306 26,910 (36,579 ) 9,669 3,306 Other comprehensive loss (65,172 ) (65,172 ) (42,574 ) 107,746 (65,172 ) Comprehensive loss $ (61,866 ) $ (38,262 ) $ (79,153 ) $ 117,415 $ (61,866 ) Following is the condensed consolidating statement of cash flows for the six months ended June 30, 2016 (in thousands): Clean Harbors, Inc. U.S. Guarantor Subsidiaries Foreign Non-Guarantor Subsidiaries Consolidating Adjustments Total Net cash from (used in) operating activities $ 42,990 $ 65,860 $ 11,201 $ — $ 120,051 Cash flows used in investing activities: Additions to property, plant and equipment — (105,175 ) (18,354 ) — (123,529 ) Proceeds from sales of fixed assets — 694 1,974 — 2,668 Acquisitions, net of cash acquired — (48,989 ) (10,000 ) — (58,989 ) Costs to obtain or renew permits — (908 ) (65 ) — (973 ) Purchase of available-for-sale securities (102 ) — (496 ) — (598 ) Investment in subsidiaries (250,625 ) — — 250,625 — Intercompany — (11,827 ) — 11,827 — Net cash used in investing activities (250,727 ) (166,205 ) (26,941 ) 262,452 (181,421 ) Cash flows from (used in) financing activities: Change in uncashed checks — (9,266 ) (1,756 ) — (11,022 ) Exercise of stock options 184 — — — 184 Issuance of restricted shares, net of shares remitted (1,879 ) — — — (1,879 ) Repurchases of common stock (10,134 ) — — — (10,134 ) Excess tax benefit of stock-based compensation 2 — — — 2 Deferred financing costs paid (2,614 ) — — — (2,614 ) Issuance of senior secured notes, including premium 250,625 250,625 — (250,625 ) 250,625 Intercompany 11,827 — — (11,827 ) — Net cash from (used in) financing activities 248,011 241,359 (1,756 ) (262,452 ) 225,162 Effect of exchange rate change on cash — — 4,423 — 4,423 Increase (decrease) in cash and cash equivalents 40,274 141,014 (13,073 ) — 168,215 Cash and cash equivalents, beginning of period 11,017 83,479 90,212 — 184,708 Cash and cash equivalents, end of period $ 51,291 $ 224,493 $ 77,139 $ — $ 352,923 Following is the condensed consolidating statement of cash flows for the six months ended June 30, 2015 (in thousands): Clean Harbors, Inc. U.S. Guarantor Subsidiaries Foreign Non-Guarantor Subsidiaries Consolidating Adjustments Total Net cash from operating activities $ 4,913 $ 158,241 $ 30,661 $ — $ 193,815 Cash flows used in investing activities: Additions to property, plant and equipment — (104,068 ) (20,077 ) — (124,145 ) Proceeds from sale of fixed assets — 368 2,278 — 2,646 Acquisitions, net of cash acquired — (79,610 ) — — (79,610 ) Costs to obtain or renew permits — (4 ) (3,084 ) — (3,088 ) Intercompany — (31,830 ) — 31,830 — Net cash used in investing activities — (215,144 ) (20,883 ) 31,830 (204,197 ) Cash flows used in financing activities: Change in uncashed checks — (16,474 ) (5,686 ) — (22,160 ) Proceeds from exercise of stock options 397 — — — 397 Issuance of restricted shares, net of shares remitted (1,837 ) — — — (1,837 ) Repurchases of common stock (32,203 ) — — — (32,203 ) Excess tax benefit of stock-based compensation 102 — — — 102 Payments of capital leases — (193 ) (278 ) — (471 ) Intercompany 31,830 — — (31,830 ) — Net cash used in financing activities (1,711 ) (16,667 ) (5,964 ) (31,830 ) (56,172 ) Effect of exchange rate change on cash — — (6,704 ) — (6,704 ) Decrease in cash and cash equivalents 3,202 (73,570 ) (2,890 ) — (73,258 ) Cash and cash equivalents, beginning of period 1,006 154,147 91,726 — 246,879 Cash and cash equivalents, end of period $ 4,208 $ 80,577 $ 88,836 $ — $ 173,621

SUBSEQUENT EVENTS

SUBSEQUENT EVENTS	6 Months Ended
	Jun. 30, 2016
Subsequent Events [Abstract]
SUBSEQUENT EVENTS	SUBSEQUENT EVENTS During July 2016, the Company completed two acquisitions as follows: i. A privately owned company with operations primarily in the northwest region of the United States which specializes in recycling and waste management as well as operating an oil re-refinery. This site operates with a Part B permit and will be integrated across the Technical Services, Industrial and Field Services, Kleen Performance Products and SK Environmental Services segments of Clean Harbors. ii. A privately owned operating facility located in southern California which will expand the Company’s capabilities for the storage and handling of used oils and other waste. This site operates with a Part B permit and will be integrated into the SK Environmental segment of Clean Harbors. These acquisitions expand the Company's geographic footprint and presence on the west coast of the United States while also increasing capabilities across its waste network and supporting growth initiatives in the SK Environmental and Kleen Performance Products segments. The aggregate purchase price of these acquisitions was approximately $101.0 million paid in cash and subject to customary post-closing adjustments. During July 2016, the Company also entered into purchase and sale agreements for three potential acquisitions for an aggregate purchase price of approximately $50.0 million . These acquisitions are expected to be completed in August of 2016. These acquisitions will be integrated across the Kleen Performance Products and SK Environmental Services segments of Clean Harbors. On August 2, 2016 the Company entered into an agreement to sell a non-core line of business within its Industrial and Field Services segment. Proceeds are expected to be approximately $50.0 million with the sale expected to be completed during the third quarter of 2016.

SIGNIFICANT ACCOUNTING POLICI28

SIGNIFICANT ACCOUNTING POLICIES (Policies)	6 Months Ended
	Jun. 30, 2016
Accounting Policies [Abstract]
Recent Accounting Pronouncements	Recent Accounting Pronouncements Standards implemented In February 2015, the Financial Accounting Standards Board ("FASB") issued Accounting Standard Update ("ASU") 2015-02, Consolidation (Topic 810) . The amendment provides guidance regarding amendments to the consolidation analysis. The adoption of ASU 2015-02 as of January 1, 2016 did not have an impact on the Company's consolidated financial statements. In September 2015, FASB issued ASU 2015-16, Business Combinations (Topic 805) . The amendment provides guidance to simplify the accounting for adjustments made to provisional amounts recognized in a business combination. This amendment eliminates the requirement to retrospectively account for those adjustments. ASU 2015-16 should be applied prospectively to adjustments to provisional amounts that occur after the effective date of this update. The adoption of ASU 2015-16 as of January 1, 2016 did not have an impact on the Company's consolidated financial statements. Standards to be implemented The Company is currently evaluating the impact that the below standards to be implemented will have on the Company's consolidated financial statements. In February 2016, FASB issued ASU 2016-02, Leases (Topic 842) . The amendment increases transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet and disclosing key information about leasing arrangements. ASU 2016-02 should be applied using a modified retrospective approach and early adoption is permitted. The amendments in this update are effective for annual reporting periods (including interim reporting periods within those periods) beginning after December 15, 2018. In March 2016, FASB issued ASU 2016-08, Revenue from Contracts with Customers (Topic 606) . ASU 2016-08 reduces the potential for diversity in practice arising from inconsistent application of the principal versus agent guidance, as well as the cost and complexity of applying Topic 606 both at transition and on an ongoing basis. The effective date and transition requirements for the amendments in this update are the same as the effective date and transition requirements of Update 2014-09, Revenue from Contracts with Customers (Topic 606) . In March 2016, FASB issued ASU 2016-09, Compensation - Stock Compensation (Topic 718) . The amendment simplifies several aspects of the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities and classification on the statement of cash flows. ASU 2016-09 allows for retrospective or prospective application and early adoption is permitted. The amendments in this update are effective for annual reporting periods (including interim reporting periods within those periods) beginning after December 15, 2016. In April 2016, FASB issued ASU 2016-10, Revenue from Contracts with Customers (Topic 606) . ASU 2016-10 reduces the potential for diversity in initial application, as well as the cost and complexity of applying Topic 606 both at transition and on an ongoing basis. The effective date and transition requirements for the amendments in this update are the same as the effective date and transition requirements of Update 2014-09, Revenue from Contracts with Customers (Topic 606) . In May 2016, FASB issued ASU 2016-12, Revenue from Contracts with Customers (Topic 606) . ASU 2016-12 provided narrow scope improvements and practical expedients on assessing collectability, presentation of sales taxes, noncash consideration, and completed contracts and contract modifications at transition. The effective date and transition requirements for the amendments in this update are the same as the effective date and transition requirements of Update 2014-09, Revenue from Contracts with Customers (Topic 606) .

BUSINESS COMBINATIONS (Tables)

BUSINESS COMBINATIONS (Tables)	6 Months Ended
	Jun. 30, 2016
Business Combinations [Abstract]
Schedule of Business Acquisitions, by Acquisition	The following table summarizes the recognized amounts of assets acquired and liabilities assumed at April 11, 2015 (in thousands): Preliminary Allocations Measurement Period Adjustments Final Allocations Accounts receivable $ 7,109 $ 192 $ 7,301 Inventories and supplies 1,791 — 1,791 Prepaid and other current assets 1,749 (1,084 ) 665 Property, plant and equipment 30,468 (2,827 ) 27,641 Permits and other intangibles 20,000 (1,900 ) 18,100 Current liabilities (5,859 ) (25 ) (5,884 ) Closure and post-closure liabilities (1,676 ) (657 ) (2,333 ) Deferred taxes, unrecognized tax benefits and other long-term liabilities (13,081 ) 3,907 (9,174 ) Total identifiable net assets 40,501 (2,394 ) 38,107 Goodwill 36,591 4,638 41,229 Total $ 77,092 $ 2,244 $ 79,336 The components and preliminary allocation of the purchase price consist of the following amounts (in thousands): At Acquisition Dates Measurement Period Adjustments At Acquisition Dates As Reported Accounts receivable $ 9,186 $ — $ 9,186 Inventories and supplies 9,431 — 9,431 Prepaid and other current assets 433 — 433 Property, plant and equipment 45,781 (1,477 ) 44,304 Permits and other intangibles 1,205 900 2,105 Current liabilities (7,119 ) — (7,119 ) Deferred taxes, unrecognized tax benefits and other long-term liabilities (548 ) — (548 ) Total identifiable net assets 58,369 (577 ) 57,792 Goodwill 620 577 1,197 Total $ 58,989 $ — $ 58,989

INVENTORIES AND SUPPLIES (Table

INVENTORIES AND SUPPLIES (Tables)	6 Months Ended
	Jun. 30, 2016
Inventory Disclosure [Abstract]
Schedule of Inventory	Inventories and supplies consisted of the following (in thousands): June 30, 2016 December 31, 2015 Oil and oil products $ 46,671 $ 33,603 Supplies and drums 78,168 78,132 Solvent and solutions 8,756 8,868 Modular camp accommodations 15,298 15,126 Other 13,511 13,792 Total inventories and supplies $ 162,404 $ 149,521

PROPERTY, PLANT AND EQUIPMENT (

PROPERTY, PLANT AND EQUIPMENT (Tables)	6 Months Ended
	Jun. 30, 2016
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	Property, plant and equipment consisted of the following (in thousands): June 30, 2016 December 31, 2015 Land $ 104,533 $ 100,582 Asset retirement costs (non-landfill) 12,187 12,434 Landfill assets 144,540 136,624 Buildings and improvements 354,470 344,209 Camp equipment 158,394 149,361 Vehicles 538,170 500,619 Equipment 1,414,946 1,328,915 Furniture and fixtures 5,528 5,337 Construction in progress 146,199 113,657 2,878,967 2,691,738 Less - accumulated depreciation and amortization 1,283,980 1,159,271 Total property, plant and equipment, net $ 1,594,987 $ 1,532,467

GOODWILL AND OTHER INTANGIBLE32

GOODWILL AND OTHER INTANGIBLE ASSETS (Tables)	6 Months Ended
	Jun. 30, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of changes to goodwill	The changes in goodwill for the six months ended June 30, 2016 were as follows (in thousands): Technical Services Industrial & Field Services Kleen Performance Products SK Environmental Services Lodging Services Oil and Gas Field Services Totals Balance at January 1, 2016 $ 49,267 $ 105,286 $ 49,755 $ 216,589 $ 32,208 $ — $ 453,105 Acquired from acquisitions — — 1,197 — — — 1,197 Measurement period adjustment from prior acquisitions — — — 2,095 — — 2,095 Foreign currency translation and other (579 ) 1,319 157 2,140 2,057 — 5,094 Balance at June 30, 2016 $ 48,688 $ 106,605 $ 51,109 $ 220,824 $ 34,265 $ — $ 461,491
Summary of amortizable other intangible assets	As of June 30, 2016 and December 31, 2015 , the Company's finite-lived and indefinite-lived intangible assets consisted of the following (in thousands): June 30, 2016 December 31, 2015 Cost Accumulated Net Weighted Cost Accumulated Net Weighted Permits $ 162,611 $ 64,533 $ 98,078 20.7 $ 161,396 $ 61,142 $ 100,254 19.0 Customer and supplier relationships 379,236 115,500 263,736 9.5 374,866 99,463 275,403 10.1 Other intangible assets 33,984 26,517 7,467 1.2 31,416 22,581 8,835 1.5 Total amortizable permits and other intangible assets 575,831 206,550 369,281 9.3 567,678 183,186 384,492 10.0 Trademarks and trade names 122,943 — 122,943 Indefinite 122,326 — 122,326 Indefinite Total permits and other intangible assets $ 698,774 $ 206,550 $ 492,224 $ 690,004 $ 183,186 $ 506,818
Schedule of expected amortization for the net carrying amount of finite lived intangible assets	The expected amortization of the net carrying amount of finite-lived intangible assets at June 30, 2016 was as follows (in thousands): Years Ending December 31, Expected Amortization 2016 (six months) $ 19,941 2017 35,033 2018 31,795 2019 28,897 2020 26,277 Thereafter 227,338 $ 369,281

ACCRUED EXPENSES (Tables)

ACCRUED EXPENSES (Tables)	6 Months Ended
	Jun. 30, 2016
Payables and Accruals [Abstract]
Accrued expenses	Accrued expenses consisted of the following at June 30, 2016 and December 31, 2015 (in thousands): June 30, 2016 December 31, 2015 Insurance $ 57,273 $ 55,899 Interest 21,587 20,500 Accrued compensation and benefits 50,275 35,646 Income, real estate, sales and other taxes 39,623 37,095 Other 35,055 44,520 $ 203,813 $ 193,660

CLOSURE AND POST-CLOSURE LIAB34

CLOSURE AND POST-CLOSURE LIABILITIES (Tables)	6 Months Ended
	Jun. 30, 2016
Asset Retirement Obligation Disclosure [Abstract]
Schedule of closure and post-closure liabilities	The changes to closure and post-closure liabilities (also referred to as “asset retirement obligations”) from January 1, 2016 through June 30, 2016 were as follows (in thousands): Landfill Non-Landfill Total Balance at January 1, 2016 $ 32,023 $ 24,226 $ 56,249 Adjustments during the measurement period related to acquisitions — 657 657 New asset retirement obligations 1,263 — 1,263 Accretion 1,384 1,150 2,534 Changes in estimates recorded to statement of operations (597 ) (91 ) (688 ) Expenditures (475 ) (570 ) (1,045 ) Currency translation and other 152 64 216 Balance at June 30, 2016 $ 33,750 $ 25,436 $ 59,186

REMEDIAL LIABILITIES (Tables)

REMEDIAL LIABILITIES (Tables)	6 Months Ended
	Jun. 30, 2016
Environmental Remediation Obligations [Abstract]
Changes to remedial liabilities	The changes to remedial liabilities for the six months ended June 30, 2016 were as follows (in thousands): Remedial Liabilities for Landfill Sites Remedial Liabilities for Inactive Sites Remedial Liabilities (Including Superfund) for Non-Landfill Operations Total Balance at January 1, 2016 $ 2,327 $ 63,613 $ 66,052 $ 131,992 Accretion 54 1,364 1,101 2,519 Changes in estimates recorded to statement of operations 70 (116 ) 419 373 Expenditures (61 ) (2,092 ) (3,256 ) (5,409 ) Currency translation and other — 52 764 816 Balance at June 30, 2016 $ 2,390 $ 62,821 $ 65,080 $ 130,291

FINANCING ARRANGEMENTS (Tables)

FINANCING ARRANGEMENTS (Tables)	6 Months Ended
	Jun. 30, 2016
Debt Disclosure [Abstract]
Summary of the entity's financial arrangements	The following table is a summary of the Company’s financing arrangements (in thousands): June 30, 2016 December 31, 2015 Senior unsecured notes, at 5.25%, due August 1, 2020 ("2020 Notes") $ 800,000 $ 800,000 Senior unsecured notes, at 5.125%, due June 1, 2021 ("2021 Notes") 845,000 595,000 Long-term obligations, at par $ 1,645,000 $ 1,395,000 Unamortized debt issuance costs and premium, net (13,119 ) (12,457 ) Long-term obligations, at carrying value $ 1,631,881 $ 1,382,543

EARNINGS (LOSS) PER SHARE (Tabl

EARNINGS (LOSS) PER SHARE (Tables)	6 Months Ended
	Jun. 30, 2016
Earnings Per Share [Abstract]
Reconciliation of basic and diluted earnings per share computations	The following are computations of basic and diluted loss per share (in thousands except for per share amounts): Three Months Ended Six Months Ended June 30, June 30, 2016 2015 2016 2015 Numerator for basic and diluted earnings per share: Net income (loss) $ 3,966 $ 10,395 $ (16,905 ) $ 3,306 Denominator: Basic shares outstanding 57,549 58,590 57,599 58,732 Dilutive effect of equity-based compensation awards 129 120 — 100 Dilutive shares outstanding 57,678 58,710 57,599 58,832 Basic earnings (loss) per share: $ 0.07 $ 0.18 $ (0.29 ) $ 0.06 Diluted earnings (loss) per share: $ 0.07 $ 0.18 $ (0.29 ) $ 0.06

ACCUMULATED OTHER COMPREHENSI38

ACCUMULATED OTHER COMPREHENSIVE LOSS (Tables)	6 Months Ended
	Jun. 30, 2016
Equity [Abstract]
Schedule of accumulated other comprehensive loss	The changes in accumulated other comprehensive loss by component and related tax effects for the six months ended June 30, 2016 were as follows (in thousands): Foreign Currency Translation Unfunded Pension Liability Total Balance at January 1, 2016 $ (252,939 ) $ (1,953 ) $ (254,892 ) Other comprehensive income before reclassifications 44,659 — 44,659 Other comprehensive income $ 44,659 $ — $ 44,659 Balance at June 30, 2016 $ (208,280 ) $ (1,953 ) $ (210,233 )

STOCK-BASED COMPENSATION (Table

STOCK-BASED COMPENSATION (Tables)	6 Months Ended
	Jun. 30, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary of total number, weighted-average grant-date fair value, and types of awards granted	The following table summarizes information about restricted stock awards for the six months ended June 30, 2016 : Restricted Stock Number of Shares Weighted Average Grant-Date Fair Value Balance at January 1, 2016 362,618 $ 55.79 Granted 299,967 $ 51.02 Vested (128,895 ) $ 55.18 Forfeited (16,785 ) $ 57.22 Balance at June 30, 2016 516,905 $ 53.12
Summary of performance stock awards	The following table summarizes information about performance stock awards for the six months ended June 30, 2016 : Performance Stock Number of Shares Weighted Average Grant-Date Fair Value Balance at January 1, 2016 187,274 $ 57.13 Granted 204,602 $ 54.30 Vested (8,420 ) $ 61.90 Forfeited (13,676 ) $ 57.23 Balance at June 30, 2016 369,780 $ 55.45

SEGMENT REPORTING (Tables)

SEGMENT REPORTING (Tables)	6 Months Ended
	Jun. 30, 2016
Segment Reporting [Abstract]
Reconciliation of third party revenues to direct revenues	The following table reconciles third party revenues to direct revenues for the three and six months ended June 30, 2016 and 2015 (in thousands): For the Three Months Ended June 30, 2016 For the Three Months Ended June 30, 2015 Third party revenues Intersegment revenues, net Corporate Items, net Direct revenues Third party revenues Intersegment revenues, net Corporate Items, net Direct revenues Technical Services $ 229,130 $ 35,578 $ 667 $ 265,375 $ 248,025 $ 38,314 $ 1,083 $ 287,422 Industrial and Field Services 153,851 (9,055 ) (286 ) 144,510 353,329 (11,230 ) (401 ) 341,698 Kleen Performance Products 86,711 (7,600 ) — 79,111 99,104 (21,428 ) (1 ) 77,675 SK Environmental Services 191,004 (21,492 ) 1 169,513 175,876 (8,802 ) 3 167,077 Lodging Services 16,418 137 14 16,569 21,171 992 80 22,243 Oil and Gas Field Services 19,232 2,432 48 21,712 38,617 2,154 40 40,811 Corporate Items 1,164 — (444 ) 720 106 — (804 ) (698 ) Total $ 697,510 $ — $ — $ 697,510 $ 936,228 $ — $ — $ 936,228 For the Six Months Ended June 30, 2016 For the Six Months Ended June 30, 2015 Third party revenues Intersegment revenues, net Corporate Items, net Direct revenues Third party revenues Intersegment revenues, net Corporate Items, net Direct revenues Technical Services $ 448,235 $ 70,422 $ 1,055 $ 519,712 $ 488,350 $ 73,218 $ 2,380 $ 563,948 Industrial and Field Services 275,428 (16,521 ) (303 ) 258,604 500,197 (17,791 ) (323 ) 482,083 Kleen Performance Products 154,254 (17,007 ) (1 ) 137,246 195,911 (39,685 ) (2 ) 156,224 SK Environmental Services 370,422 (40,606 ) 368 330,184 336,560 (20,384 ) 3 316,179 Lodging Services 32,063 401 35 32,499 55,275 1,156 97 56,528 Oil and Gas Field Services 51,248 3,311 135 54,694 92,204 3,486 49 95,739 Corporate Items 1,943 — (1,289 ) 654 230 — (2,204 ) (1,974 ) Total $ 1,333,593 $ — $ — $ 1,333,593 $ 1,668,727 $ — $ — $ 1,668,727
Reconciliation to consolidated statements of income to adjusted EBITDA	The following table presents Adjusted EBITDA information used by management by reported segment (in thousands). The Company does not allocate interest expense, income taxes, depreciation, amortization, accretion of environmental liabilities, other non-cash charges not deemed representative of fundamental segment results, and other expense (income) to its segments. For the Three Months Ended For the Six Months Ended June 30, June 30, 2016 2015 2016 2015 Adjusted EBITDA: Technical Services $ 68,891 $ 76,808 $ 129,289 $ 140,209 Industrial and Field Services 19,946 73,081 22,064 83,390 Kleen Performance Products 9,995 15,824 14,555 11,348 SK Environmental Services 45,239 41,195 80,734 68,444 Lodging Services 3,022 3,852 4,041 10,762 Oil and Gas Field Services (4,207 ) (2,182 ) (5,601 ) (779 ) Corporate Items (32,441 ) (45,456 ) (67,317 ) (71,975 ) Total $ 110,445 $ 163,122 $ 177,765 $ 241,399 Reconciliation to Consolidated Statements of Operations: Accretion of environmental liabilities 2,548 2,599 5,053 5,218 Depreciation and amortization 73,393 67,773 142,295 136,129 Goodwill impairment charge — 31,992 — 31,992 Income from operations 34,504 60,758 30,417 68,060 Other expense 189 660 539 251 Interest expense, net of interest income 21,647 19,249 40,627 38,687 Income (loss) before provision for income taxes $ 12,668 $ 40,849 $ (10,749 ) $ 29,122
PP&E, intangible assets and total assets by segment	The following table presents certain assets by reportable segment and in the aggregate (in thousands): June 30, 2016 Technical Industrial and Field Kleen Performance Products SK Environmental Services Lodging Services Oil and Gas Field Corporate Totals Property, plant and equipment, net $ 507,996 $ 231,334 $ 211,082 $ 302,260 $ 104,386 $ 146,423 $ 91,506 $ 1,594,987 Goodwill 48,688 106,605 51,109 220,824 34,265 — — 461,491 Permits and other intangibles, net 69,683 13,587 139,867 251,087 6,495 11,505 — 492,224 Total assets $ 823,881 $ 375,796 $ 520,943 $ 852,082 $ 181,031 $ 235,775 $ 702,873 $ 3,692,381 December 31, 2015 Technical Industrial and Field Kleen Performance Products SK Environmental Services Lodging Services Oil and Gas Field Corporate Totals Property, plant and equipment, net $ 483,425 $ 237,660 $ 193,855 $ 264,539 $ 105,208 $ 156,286 $ 91,494 $ 1,532,467 Goodwill 49,267 105,286 49,755 216,589 32,208 — — 453,105 Permits and other intangibles, net 73,601 14,649 140,410 256,251 7,045 14,862 — 506,818 Total assets $ 800,060 $ 368,858 $ 492,483 $ 805,488 $ 181,357 $ 244,210 $ 538,972 $ 3,431,428
Total assets by geographical area	The following table presents total assets by geographical area (in thousands): June 30, 2016 December 31, 2015 United States $ 2,837,201 $ 2,575,746 Canada 850,355 851,949 Other foreign 4,825 3,733 Total $ 3,692,381 $ 3,431,428

GUARANTOR AND NON-GUARANTOR S41

GUARANTOR AND NON-GUARANTOR SUBSIDIARIES FINANCIAL INFORMATION (Tables)	6 Months Ended
	Jun. 30, 2016
Guarantor and Non-Guarantor Subsidiaries Financial Information [Abstract]
Schedule of condensed consolidating balance sheet	Following is the condensed consolidating balance sheet at June 30, 2016 (in thousands): Clean Harbors, Inc. U.S. Guarantor Subsidiaries Foreign Non-Guarantor Subsidiaries Consolidating Adjustments Total Assets: Cash and cash equivalents $ 51,291 $ 224,493 $ 77,139 $ — $ 352,923 Intercompany receivables 181,741 302,354 30,741 (514,836 ) — Accounts receivable, net — 407,601 96,148 — 503,749 Other current assets 378 198,612 63,472 — 262,462 Property, plant and equipment, net — 1,138,285 456,702 — 1,594,987 Investments in subsidiaries 2,833,394 514,708 — (3,348,102 ) — Intercompany debt receivable — 277,623 3,701 (281,324 ) — Goodwill — 369,978 91,513 — 461,491 Permits and other intangibles, net — 423,932 68,292 — 492,224 Other long-term assets 1,412 9,559 13,574 — 24,545 Total assets $ 3,068,216 $ 3,867,145 $ 901,282 $ (4,144,262 ) $ 3,692,381 Liabilities and Stockholders’ Equity: Current liabilities $ 21,852 $ 427,367 $ 71,202 $ — $ 520,421 Intercompany payables 294,439 217,430 2,967 (514,836 ) — Closure, post-closure and remedial liabilities, net — 150,182 15,252 — 165,434 Long-term obligations 1,631,881 — — — 1,631,881 Intercompany debt payable 3,701 — 277,623 (281,324 ) — Other long-term liabilities — 238,772 19,530 — 258,302 Total liabilities 1,951,873 1,033,751 386,574 (796,160 ) 2,576,038 Stockholders’ equity 1,116,343 2,833,394 514,708 (3,348,102 ) 1,116,343 Total liabilities and stockholders’ equity $ 3,068,216 $ 3,867,145 $ 901,282 $ (4,144,262 ) $ 3,692,381 Following is the condensed consolidating balance sheet at December 31, 2015 (in thousands): Clean Harbors, Inc. U.S. Guarantor Subsidiaries Foreign Non-Guarantor Subsidiaries Consolidating Adjustments Total Assets: Cash and cash equivalents $ 11,017 $ 83,479 $ 90,212 $ — $ 184,708 Intercompany receivables 164,709 213,243 39,804 (417,756 ) — Accounts receivables, net — 404,580 91,424 — 496,004 Other current assets — 179,969 60,515 — 240,484 Property, plant and equipment, net — 1,082,466 450,001 — 1,532,467 Investments in subsidiaries 2,547,307 522,067 — (3,069,374 ) — Intercompany debt receivable — 260,957 3,701 (264,658 ) — Goodwill — 367,306 85,799 — 453,105 Permits and other intangibles, net — 435,080 71,738 — 506,818 Other long-term assets 1,068 10,274 6,500 — 17,842 Total assets $ 2,724,101 $ 3,559,421 $ 899,694 $ (3,751,788 ) $ 3,431,428 Liabilities and Stockholders’ Equity: Current liabilities $ 20,813 $ 424,588 $ 71,719 $ — $ 517,120 Intercompany payables 220,762 195,287 1,707 (417,756 ) — Closure, post-closure and remedial liabilities, net — 153,190 14,656 — 167,846 Long-term obligations 1,382,543 — — — 1,382,543 Intercompany debt payable 3,701 — 260,957 (264,658 ) — Other long-term liabilities — 239,049 28,588 — 267,637 Total liabilities 1,627,819 1,012,114 377,627 (682,414 ) 2,335,146 Stockholders’ equity 1,096,282 2,547,307 522,067 (3,069,374 ) 1,096,282 Total liabilities and stockholders’ equity $ 2,724,101 $ 3,559,421 $ 899,694 $ (3,751,788 ) $ 3,431,428
Schedule of condensed consolidating statement of income	Following is the consolidating statement of operations for the three months ended June 30, 2016 (in thousands): Clean Harbors, Inc. U.S. Guarantor Subsidiaries Foreign Non-Guarantor Subsidiaries Consolidating Adjustments Total Revenues Service revenues $ — $ 456,013 $ 139,413 $ (10,864 ) $ 584,562 Product revenues — 95,648 19,391 (2,091 ) 112,948 Total revenues — 551,661 158,804 (12,955 ) 697,510 Cost of revenues (exclusive of items shown separately below) Service cost of revenues (587 ) 292,343 107,792 (10,864 ) 388,684 Product cost of revenues — 79,108 14,301 (2,091 ) 91,318 Total cost of revenues (587 ) 371,451 122,093 (12,955 ) 480,002 Selling, general and administrative expenses 37 83,882 23,144 — 107,063 Accretion of environmental liabilities — 2,313 235 — 2,548 Depreciation and amortization — 50,696 22,697 — 73,393 Income (loss) from operations 550 43,319 (9,365 ) — 34,504 Other expense (income) — 400 (589 ) — (189 ) Interest (expense) income (22,962 ) 1,284 31 — (21,647 ) Equity in earnings of subsidiaries, net of taxes 17,413 (9,195 ) — (8,218 ) — Intercompany interest income (expense) — 5,497 (5,497 ) — — (Loss) income before (benefit) provision for income taxes (4,999 ) 41,305 (15,420 ) (8,218 ) 12,668 (Benefit) provision for income taxes (8,965 ) 23,892 (6,225 ) — 8,702 Net income (loss) 3,966 17,413 (9,195 ) (8,218 ) 3,966 Other comprehensive loss (1,178 ) (1,178 ) (597 ) 1,775 (1,178 ) Comprehensive income (loss) $ 2,788 $ 16,235 $ (9,792 ) $ (6,443 ) $ 2,788 Following is the consolidating statement of operations for the three months ended June 30, 2015 (in thousands): Clean Harbors, Inc. U.S. Guarantor Subsidiaries Foreign Non-Guarantor Subsidiaries Consolidating Adjustments Total Revenues Service revenues $ — $ 628,408 $ 190,657 $ (17,718 ) $ 801,347 Product revenues — 115,335 22,444 (2,898 ) 134,881 Total revenues — 743,743 213,101 (20,616 ) 936,228 Cost of revenues (exclusive of items shown separately below) Service cost of revenues — 415,111 147,477 (17,718 ) 544,870 Product cost of revenues — 98,258 12,458 (2,898 ) 107,818 Total cost of revenues — 513,369 159,935 (20,616 ) 652,688 Selling, general and administrative expenses 25 93,677 26,716 — 120,418 Accretion of environmental liabilities — 2,287 312 — 2,599 Depreciation and amortization — 44,602 23,171 — 67,773 Goodwill impairment charge — 4,164 27,828 — 31,992 (Loss) income from operations (25 ) 85,644 (24,861 ) — 60,758 Other income (expense) — 168 (828 ) — (660 ) Interest (expense) income (19,652 ) 324 79 — (19,249 ) Equity in earnings of subsidiaries, net of taxes 22,201 (29,550 ) — 7,349 — Intercompany interest income (expense) — 6,036 (6,036 ) — — Income (loss) before (benefit) provision for income taxes 2,524 62,622 (31,646 ) 7,349 40,849 (Benefit) provision for income taxes (7,871 ) 40,421 (2,096 ) — 30,454 Net income (loss) 10,395 22,201 (29,550 ) 7,349 10,395 Other comprehensive income 12,231 12,231 8,061 (20,292 ) 12,231 Comprehensive income (loss) $ 22,626 $ 34,432 $ (21,489 ) $ (12,943 ) $ 22,626 Following is the consolidating statement of operations for the six months ended June 30, 2016 (in thousands): Clean Harbors, Inc. U.S. Guarantor Subsidiaries Foreign Non-Guarantor Subsidiaries Consolidating Adjustments Total Revenues Service revenues $ — $ 884,490 $ 253,436 $ (23,133 ) $ 1,114,793 Product revenues — 185,236 38,104 (4,540 ) 218,800 Total revenues — 1,069,726 291,540 (27,673 ) 1,333,593 Cost of revenues (exclusive of items shown separately below) Service cost of revenues (587 ) 575,307 211,083 (23,133 ) 762,670 Product cost of revenues — 158,462 27,689 (4,540 ) 181,611 Total cost of revenues (587 ) 733,769 238,772 (27,673 ) 944,281 Selling, general and administrative expenses 61 164,537 46,949 — 211,547 Accretion of environmental liabilities — 4,603 450 — 5,053 Depreciation and amortization — 99,391 42,904 — 142,295 Income (loss) from operations 526 67,426 (37,535 ) — 30,417 Other income (expense) — 312 (851 ) — (539 ) Interest (expense) income (43,105 ) 2,395 83 — (40,627 ) Equity in earnings of subsidiaries, net of taxes 8,642 (35,690 ) — 27,048 — Intercompany interest income (expense) — 10,656 (10,656 ) — — (Loss) income before (benefit) provision for income taxes (33,937 ) 45,099 (48,959 ) 27,048 (10,749 ) (Benefit) provision for income taxes (17,032 ) 36,457 (13,269 ) — 6,156 Net (loss) income (16,905 ) 8,642 (35,690 ) 27,048 (16,905 ) Other comprehensive gain 44,659 44,659 28,330 (72,989 ) 44,659 Comprehensive gain (loss) $ 27,754 $ 53,301 $ (7,360 ) $ (45,941 ) $ 27,754 Following is the consolidating statement of operations for the six months ended June 30, 2015 (in thousands): Clean Harbors, Inc. U.S. Guarantor Subsidiaries Foreign Non-Guarantor Subsidiaries Consolidating Adjustments Total Revenues Service revenues $ — $ 1,046,925 $ 384,110 $ (33,358 ) $ 1,397,677 Product revenues — 231,871 45,648 (6,469 ) 271,050 Total revenues — 1,278,796 429,758 (39,827 ) 1,668,727 Cost of revenues (exclusive of items shown separately below) Service cost of revenues — 692,713 301,905 (33,358 ) 961,260 Product cost of revenues — 213,544 30,860 (6,469 ) 237,935 Total cost of revenues — 906,257 332,765 (39,827 ) 1,199,195 Selling, general and administrative expenses 50 174,661 53,422 — 228,133 Accretion of environmental liabilities — 4,593 625 — 5,218 Depreciation and amortization — 90,403 45,726 — 136,129 Goodwill impairment charge — 4,164 27,828 — 31,992 (Loss) income from operations (50 ) 98,718 (30,608 ) — 68,060 Other income (expense) — 279 (530 ) — (251 ) Interest (expense) income (39,291 ) 502 102 — (38,687 ) Equity in earnings of subsidiaries, net of taxes 26,910 (36,579 ) — 9,669 — Intercompany interest income (expense) — 12,013 (12,013 ) — — (Loss) income before (benefit) provision for income taxes (12,431 ) 74,933 (43,049 ) 9,669 29,122 (Benefit) provision for income taxes (15,737 ) 48,023 (6,470 ) — 25,816 Net income (loss) 3,306 26,910 (36,579 ) 9,669 3,306 Other comprehensive loss (65,172 ) (65,172 ) (42,574 ) 107,746 (65,172 ) Comprehensive loss $ (61,866 ) $ (38,262 ) $ (79,153 ) $ 117,415 $ (61,866 )
Schedule of condensed consolidating statement of cash flows	Following is the condensed consolidating statement of cash flows for the six months ended June 30, 2016 (in thousands): Clean Harbors, Inc. U.S. Guarantor Subsidiaries Foreign Non-Guarantor Subsidiaries Consolidating Adjustments Total Net cash from (used in) operating activities $ 42,990 $ 65,860 $ 11,201 $ — $ 120,051 Cash flows used in investing activities: Additions to property, plant and equipment — (105,175 ) (18,354 ) — (123,529 ) Proceeds from sales of fixed assets — 694 1,974 — 2,668 Acquisitions, net of cash acquired — (48,989 ) (10,000 ) — (58,989 ) Costs to obtain or renew permits — (908 ) (65 ) — (973 ) Purchase of available-for-sale securities (102 ) — (496 ) — (598 ) Investment in subsidiaries (250,625 ) — — 250,625 — Intercompany — (11,827 ) — 11,827 — Net cash used in investing activities (250,727 ) (166,205 ) (26,941 ) 262,452 (181,421 ) Cash flows from (used in) financing activities: Change in uncashed checks — (9,266 ) (1,756 ) — (11,022 ) Exercise of stock options 184 — — — 184 Issuance of restricted shares, net of shares remitted (1,879 ) — — — (1,879 ) Repurchases of common stock (10,134 ) — — — (10,134 ) Excess tax benefit of stock-based compensation 2 — — — 2 Deferred financing costs paid (2,614 ) — — — (2,614 ) Issuance of senior secured notes, including premium 250,625 250,625 — (250,625 ) 250,625 Intercompany 11,827 — — (11,827 ) — Net cash from (used in) financing activities 248,011 241,359 (1,756 ) (262,452 ) 225,162 Effect of exchange rate change on cash — — 4,423 — 4,423 Increase (decrease) in cash and cash equivalents 40,274 141,014 (13,073 ) — 168,215 Cash and cash equivalents, beginning of period 11,017 83,479 90,212 — 184,708 Cash and cash equivalents, end of period $ 51,291 $ 224,493 $ 77,139 $ — $ 352,923 Following is the condensed consolidating statement of cash flows for the six months ended June 30, 2015 (in thousands): Clean Harbors, Inc. U.S. Guarantor Subsidiaries Foreign Non-Guarantor Subsidiaries Consolidating Adjustments Total Net cash from operating activities $ 4,913 $ 158,241 $ 30,661 $ — $ 193,815 Cash flows used in investing activities: Additions to property, plant and equipment — (104,068 ) (20,077 ) — (124,145 ) Proceeds from sale of fixed assets — 368 2,278 — 2,646 Acquisitions, net of cash acquired — (79,610 ) — — (79,610 ) Costs to obtain or renew permits — (4 ) (3,084 ) — (3,088 ) Intercompany — (31,830 ) — 31,830 — Net cash used in investing activities — (215,144 ) (20,883 ) 31,830 (204,197 ) Cash flows used in financing activities: Change in uncashed checks — (16,474 ) (5,686 ) — (22,160 ) Proceeds from exercise of stock options 397 — — — 397 Issuance of restricted shares, net of shares remitted (1,837 ) — — — (1,837 ) Repurchases of common stock (32,203 ) — — — (32,203 ) Excess tax benefit of stock-based compensation 102 — — — 102 Payments of capital leases — (193 ) (278 ) — (471 ) Intercompany 31,830 — — (31,830 ) — Net cash used in financing activities (1,711 ) (16,667 ) (5,964 ) (31,830 ) (56,172 ) Effect of exchange rate change on cash — — (6,704 ) — (6,704 ) Decrease in cash and cash equivalents 3,202 (73,570 ) (2,890 ) — (73,258 ) Cash and cash equivalents, beginning of period 1,006 154,147 91,726 — 246,879 Cash and cash equivalents, end of period $ 4,208 $ 80,577 $ 88,836 $ — $ 173,621

BUSINESS COMBINATIONS (Narrativ

BUSINESS COMBINATIONS (Narrative) (Details) $ in Thousands	Apr. 11, 2015USD ($)	Dec. 31, 2015USD ($)	Jun. 30, 2016USD ($)	Jun. 30, 2016USD ($)aquisition
Business Acquisition [Line Items]
Goodwill, acquired during period				$ 1,197
2016 Acquisitions
Business Acquisition [Line Items]
Number of acquisitions | aquisition				2
Purchase price				$ 59,000
Revenue from acquisitions			$ 12,100	12,100
Acquisition-related costs			$ 400	$ 500
Thermo Fluids Inc.
Business Acquisition [Line Items]
Purchase price	$ 79,300
Privately Owned Domestic Company
Business Acquisition [Line Items]
Payments to acquire business		$ 14,700
Goodwill, acquired during period		$ 7,400

BUSINESS COMBINATIONS (Assets A

BUSINESS COMBINATIONS (Assets Acquired and Liabilities Assumed) (Details) - USD ($) $ in Thousands	6 Months Ended	15 Months Ended
	Jun. 30, 2016	Jun. 30, 2016	Dec. 31, 2015	Apr. 11, 2015
Business Acquisition [Line Items]
Goodwill	$ 461,491	$ 461,491	$ 453,105
2016 Acquisitions
Business Acquisition [Line Items]
Accounts receivable	9,186	9,186
Measurement period adjustments, accounts receivable	0
Inventories and supplies	9,431	9,431
Measurement period adjustment, inventories and supplies	0
Prepaid and other current assets	433	433
Measurement period adjustment, prepaid and other current assets	0
Property, plant and equipment	44,304	44,304
Measurement period adjustments, property, plant and equipment	(1,477)
Permits and other intangibles	2,105	2,105
Measurement period adjustments, permits and other intangibles	900
Current liabilities	(7,119)	(7,119)
Measurement period adjustments, current liabilities	0
Deferred taxes, unrecognized tax benefits and other long-term liabilities	(548)	(548)
Measurement period adjustments, deferred taxes, unrecognized tax benefits and other long-term liabilities	0
Total identifiable net assets	57,792	57,792
Measurement period adjustments, total identifiable net assets	(577)
Goodwill	1,197	1,197
Measurement period adjustments, goodwill	577
Total	58,989	58,989
Measurement period adjustments, total	0
Thermo Fluids Inc.
Business Acquisition [Line Items]
Accounts receivable	7,301	7,301
Measurement period adjustments, accounts receivable		192
Inventories and supplies	1,791	1,791
Measurement period adjustment, inventories and supplies		0
Prepaid and other current assets	665	665
Measurement period adjustment, prepaid and other current assets		(1,084)
Property, plant and equipment	27,641	27,641
Measurement period adjustments, property, plant and equipment		(2,827)
Permits and other intangibles	18,100	18,100
Measurement period adjustments, permits and other intangibles		(1,900)
Current liabilities	(5,884)	(5,884)
Measurement period adjustments, current liabilities		(25)
Closure and post-closure liabilities	(2,333)	(2,333)
Measurement period adjustments, closure and post-closure liabilities		(657)
Deferred taxes, unrecognized tax benefits and other long-term liabilities	(9,174)	(9,174)
Measurement period adjustments, deferred taxes, unrecognized tax benefits and other long-term liabilities		3,907
Total identifiable net assets	38,107	38,107
Measurement period adjustments, total identifiable net assets		(2,394)
Goodwill	41,229	41,229
Measurement period adjustments, goodwill		4,638
Total	79,336	79,336
Measurement period adjustments, total		2,244
At Acquisition Dates | 2016 Acquisitions
Business Acquisition [Line Items]
Accounts receivable	9,186	9,186
Inventories and supplies	9,431	9,431
Prepaid and other current assets	433	433
Property, plant and equipment	45,781	45,781
Permits and other intangibles	1,205	1,205
Current liabilities	(7,119)	(7,119)
Deferred taxes, unrecognized tax benefits and other long-term liabilities	(548)	(548)
Total identifiable net assets	58,369	58,369
Goodwill	620	620
Total	$ 58,989	$ 58,989
At Acquisition Dates | Thermo Fluids Inc.
Business Acquisition [Line Items]
Accounts receivable				$ 7,109
Inventories and supplies				1,791
Prepaid and other current assets				1,749
Property, plant and equipment				30,468
Permits and other intangibles				20,000
Current liabilities				(5,859)
Closure and post-closure liabilities				(1,676)
Deferred taxes, unrecognized tax benefits and other long-term liabilities				(13,081)
Total identifiable net assets				40,501
Goodwill				36,591
Total				$ 77,092

INVENTORIES AND SUPPLIES (Detai

INVENTORIES AND SUPPLIES (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Inventory Disclosure [Abstract]
Oil and oil products	$ 46,671	$ 33,603
Supplies and drums	78,168	78,132
Solvent and solutions	8,756	8,868
Modular camp accommodations	15,298	15,126
Other	13,511	13,792
Total inventories and supplies	$ 162,404	$ 149,521

PROPERTY, PLANT AND EQUIPMENT45

PROPERTY, PLANT AND EQUIPMENT (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Total property, plant and equipment, gross	$ 2,878,967		$ 2,878,967		$ 2,691,738
Less - accumulated depreciation and amortization	1,283,980		1,283,980		1,159,271
Total property, plant and equipment, net	1,594,987		1,594,987		1,532,467
Interest costs capitalized adjustment	1,300	$ 400	2,500	$ 600
Depreciation inclusive of amortization	63,500	$ 58,900	122,800	$ 116,300
Land
Property, Plant and Equipment [Line Items]
Total property, plant and equipment, gross	104,533		104,533		100,582
Asset retirement costs (non-landfill)
Property, Plant and Equipment [Line Items]
Total property, plant and equipment, gross	12,187		12,187		12,434
Landfill assets
Property, Plant and Equipment [Line Items]
Total property, plant and equipment, gross	144,540		144,540		136,624
Buildings and improvements
Property, Plant and Equipment [Line Items]
Total property, plant and equipment, gross	354,470		354,470		344,209
Camp equipment
Property, Plant and Equipment [Line Items]
Total property, plant and equipment, gross	158,394		158,394		149,361
Vehicles
Property, Plant and Equipment [Line Items]
Total property, plant and equipment, gross	538,170		538,170		500,619
Equipment
Property, Plant and Equipment [Line Items]
Total property, plant and equipment, gross	1,414,946		1,414,946		1,328,915
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Total property, plant and equipment, gross	5,528		5,528		5,337
Construction in progress
Property, Plant and Equipment [Line Items]
Total property, plant and equipment, gross	$ 146,199		$ 146,199		$ 113,657

GOODWILL AND OTHER INTANGIBLE46

GOODWILL AND OTHER INTANGIBLE ASSETS (Rollforward of Goodwill) (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2016USD ($)
Goodwill [Roll Forward]
Balance at beginning of year	$ 453,105
Acquired from acquisitions	1,197
Measurement period adjustment from prior acquisitions	2,095
Foreign currency translation and other	5,094
Balance at end of year	461,491
Technical Services
Goodwill [Roll Forward]
Balance at beginning of year	49,267
Balance at end of year	48,688
Industrial and Field Services
Goodwill [Roll Forward]
Balance at beginning of year	105,286
Balance at end of year	106,605
Kleen Performance Products
Goodwill [Roll Forward]
Balance at beginning of year	49,755
Balance at end of year	51,109
SK Environmental Services
Goodwill [Roll Forward]
Balance at beginning of year	216,589
Balance at end of year	220,824
Lodging Services
Goodwill [Roll Forward]
Balance at beginning of year	32,208
Balance at end of year	34,265
Oil and Gas Field Services
Goodwill [Roll Forward]
Balance at beginning of year	0
Balance at end of year	0
Operating Segments | Technical Services
Goodwill [Roll Forward]
Balance at beginning of year	49,267
Acquired from acquisitions	0
Measurement period adjustment from prior acquisitions	0
Foreign currency translation and other	(579)
Balance at end of year	48,688
Operating Segments | Industrial and Field Services
Goodwill [Roll Forward]
Balance at beginning of year	105,286
Acquired from acquisitions	0
Measurement period adjustment from prior acquisitions	0
Foreign currency translation and other	1,319
Balance at end of year	106,605
Operating Segments | Kleen Performance Products
Goodwill [Roll Forward]
Balance at beginning of year	49,755
Acquired from acquisitions	1,197
Measurement period adjustment from prior acquisitions	0
Foreign currency translation and other	157
Balance at end of year	51,109
Operating Segments | SK Environmental Services
Goodwill [Roll Forward]
Balance at beginning of year	216,589
Acquired from acquisitions	0
Measurement period adjustment from prior acquisitions	2,095
Foreign currency translation and other	2,140
Balance at end of year	220,824
Operating Segments | Lodging Services
Goodwill [Roll Forward]
Balance at beginning of year	32,208
Acquired from acquisitions	0
Measurement period adjustment from prior acquisitions	0
Foreign currency translation and other	2,057
Balance at end of year	34,265
Operating Segments | Oil and Gas Field Services
Goodwill [Roll Forward]
Balance at beginning of year	0
Acquired from acquisitions	0
Measurement period adjustment from prior acquisitions	0
Foreign currency translation and other	0
Balance at end of year	$ 0

GOODWILL AND OTHER INTANGIBLE47

GOODWILL AND OTHER INTANGIBLE ASSETS (Amortizable Other Intangible Assets) (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2016	Dec. 31, 2015
Schedule of Finite-lived and Indefinite-lived Intangible Assets [Line Items]
Cost	$ 575,831	$ 567,678
Accumulated Amortization	206,550	183,186
Net	$ 369,281	$ 384,492
Weighted Average Remaining Amortization Period (in years)	9 years 3 months 4 days	10 years
Total permits and other intangible assets, Cost	$ 698,774	$ 690,004
Total permits and other intangible assets, Net	492,224	506,818
Trademarks and trade names
Schedule of Finite-lived and Indefinite-lived Intangible Assets [Line Items]
Trademarks and trade names	122,943	122,326
Permits
Schedule of Finite-lived and Indefinite-lived Intangible Assets [Line Items]
Cost	162,611	161,396
Accumulated Amortization	64,533	61,142
Net	$ 98,078	$ 100,254
Weighted Average Remaining Amortization Period (in years)	20 years 7 months 50 days	19 years
Customer and supplier relationships
Schedule of Finite-lived and Indefinite-lived Intangible Assets [Line Items]
Cost	$ 379,236	$ 374,866
Accumulated Amortization	115,500	99,463
Net	$ 263,736	$ 275,403
Weighted Average Remaining Amortization Period (in years)	9 years 6 months	10 years 30 days
Other intangible assets
Schedule of Finite-lived and Indefinite-lived Intangible Assets [Line Items]
Cost	$ 33,984	$ 31,416
Accumulated Amortization	26,517	22,581
Net	$ 7,467	$ 8,835
Weighted Average Remaining Amortization Period (in years)	1 year 2 months	1 year 6 months

GOODWILL AND OTHER INTANGIBLE48

GOODWILL AND OTHER INTANGIBLE ASSETS (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization of permits and other intangible assets	$ 9.9	$ 8.8	$ 19.5	$ 19.8

GOODWILL AND OTHER INTANGIBLE49

GOODWILL AND OTHER INTANGIBLE ASSETS (Expected Future Amortization) (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
2016 (six months)	$ 19,941
2,017	35,033
2,018	31,795
2,019	28,897
2,020	26,277
Thereafter	227,338
Net	$ 369,281	$ 384,492

ACCRUED EXPENSES (Details)

ACCRUED EXPENSES (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Payables and Accruals [Abstract]
Insurance	$ 57,273	$ 55,899
Interest	21,587	20,500
Accrued compensation and benefits	50,275	35,646
Income, real estate, sales and other taxes	39,623	37,095
Other	35,055	44,520
Total accrued expenses	$ 203,813	$ 193,660

CLOSURE AND POST-CLOSURE LIAB51

CLOSURE AND POST-CLOSURE LIABILITIES (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2016USD ($)
Changes to post-closure liabilities
Balance at January 1, 2016	$ 56,249
Adjustments during the measurement period related to acquisitions	657
New asset retirement obligations	1,263
Accretion	2,534
Changes in estimates recorded to statement of operations	(688)
Expenditures	(1,045)
Currency translation and other	216
Balance at June 30, 2016	$ 59,186
Credit-adjusted risk-free rate (as a percent)	6.23%
Landfill Retirement Liability
Changes to post-closure liabilities
Balance at January 1, 2016	$ 32,023
Adjustments during the measurement period related to acquisitions	0
New asset retirement obligations	1,263
Accretion	1,384
Changes in estimates recorded to statement of operations	(597)
Expenditures	(475)
Currency translation and other	152
Balance at June 30, 2016	33,750
Non-Landfill Retirement Liability
Changes to post-closure liabilities
Balance at January 1, 2016	24,226
Adjustments during the measurement period related to acquisitions	657
New asset retirement obligations	0
Accretion	1,150
Changes in estimates recorded to statement of operations	(91)
Expenditures	(570)
Currency translation and other	64
Balance at June 30, 2016	$ 25,436

REMEDIAL LIABILITIES (Details)

REMEDIAL LIABILITIES (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2016USD ($)
Accrual for Environmental Loss Contingencies [Roll Forward]
Balance at beginning of year	$ 131,992
Accretion	2,519
Changes in estimates recorded to statement of operations	373
Expenditures	(5,409)
Currency translation and other	816
Balance at end of year	130,291
Remedial Liabilities for Landfill Sites
Accrual for Environmental Loss Contingencies [Roll Forward]
Balance at beginning of year	2,327
Accretion	54
Changes in estimates recorded to statement of operations	70
Expenditures	(61)
Currency translation and other	0
Balance at end of year	2,390
Remedial Liabilities for Inactive Sites
Accrual for Environmental Loss Contingencies [Roll Forward]
Balance at beginning of year	63,613
Accretion	1,364
Changes in estimates recorded to statement of operations	(116)
Expenditures	(2,092)
Currency translation and other	52
Balance at end of year	62,821
Remedial Liabilities (Including Superfund) for Non-Landfill Operations
Accrual for Environmental Loss Contingencies [Roll Forward]
Balance at beginning of year	66,052
Accretion	1,101
Changes in estimates recorded to statement of operations	419
Expenditures	(3,256)
Currency translation and other	764
Balance at end of year	$ 65,080

FINANCING ARRANGEMENTS (Details

FINANCING ARRANGEMENTS (Details) - USD ($)	6 Months Ended
	Jun. 30, 2016	Mar. 14, 2016	Dec. 31, 2015	Dec. 07, 2012
Financing arrangements
Long-term obligations, at par	$ 1,645,000,000		$ 1,395,000,000
Unamortized debt issuance costs and premium, net	(13,119,000)		(12,457,000)
Long-term obligations, at carrying value	1,631,881,000		1,382,543,000
Revolving credit facility, amount outstanding	0		0
Line of credit facility available borrowing capacity	190,000,000		178,500,000
Letters of credit amount outstanding	$ 140,500,000		144,600,000
Parent and domestic subsidiaries
Financing arrangements
Credit available subject to percentage of accounts receivable	85.00%
Credit available subject to percentage of cash deposited	100.00%
Canadian subsidiaries
Financing arrangements
Credit available subject to percentage of accounts receivable	85.00%
Credit available subject to percentage of cash deposited	100.00%
Unsecured debt | Senior unsecured notes, at 5.25%, due August 1, 2020 (2020 Notes)
Financing arrangements
Long-term obligations, at par	$ 800,000,000		$ 800,000,000
Stated interest rate	5.25%		5.25%
Fair value	$ 819,000,000		$ 812,000,000
Unsecured debt | Senior unsecured notes, at 5.125%, due June 1, 2021 (2021 Notes)
Financing arrangements
Long-term obligations, at par	$ 845,000,000		$ 595,000,000
Stated interest rate	5.125%		5.125%
Fair value	$ 859,800,000		$ 599,500,000
Issuance of debt	$ 250,000,000	$ 250,000,000		$ 600,000,000

EARNINGS (LOSS) PER SHARE (Comp

EARNINGS (LOSS) PER SHARE (Computation of Basic and Diluted Earnings Per Share)(Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Numerator for basic and diluted earnings per share:
Net income (loss)	$ 3,966	$ 10,395	$ (16,905)	$ 3,306
Denominator:
Basic shares outstanding (in shares)	57,549	58,590	57,599	58,732
Dilutive effect of equity-based compensation awards (in shares)	129	120	0	100
Dilutive shares outstanding (in shares)	57,678	58,710	57,599	58,832
Basic earnings (loss) per share (in USD per share)	$ 0.07	$ 0.18	$ (0.29)	$ 0.06
Diluted earnings (loss) per share (in USD per share)	$ 0.07	$ 0.18	$ (0.29)	$ 0.06

EARNINGS (LOSS) PER SHARE (Narr

EARNINGS (LOSS) PER SHARE (Narrative) (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Performance stock awards
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares excluded from computation of earning per share (in shares)	348,197	196,180		196,180
Restricted Stock Awards
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares excluded from computation of earning per share (in shares)	9,537	11,075		38,171
Stock Options, Restricted Stock Awards, and Performance Awards
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares excluded from computation of earning per share (in shares)			886,685

ACCUMULATED OTHER COMPREHENSI56

ACCUMULATED OTHER COMPREHENSIVE LOSS (Changes in Accumulated Other Comprehensive Loss by Component) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Components of Other Accumulated Income, Net of Tax [Roll Forward]
Balance at beginning of period			$ 1,096,282
Other comprehensive income	$ (1,178)	$ 12,231	44,659	$ (65,172)
Balance at end of period	1,116,343		1,116,343
Foreign Currency Translation
Components of Other Accumulated Income, Net of Tax [Roll Forward]
Balance at beginning of period			(252,939)
Other comprehensive income before reclassifications			44,659
Other comprehensive income			44,659
Balance at end of period	(208,280)		(208,280)
Unfunded Pension Liability
Components of Other Accumulated Income, Net of Tax [Roll Forward]
Balance at beginning of period			(1,953)
Other comprehensive income before reclassifications			0
Other comprehensive income			0
Balance at end of period	(1,953)		(1,953)
Total
Components of Other Accumulated Income, Net of Tax [Roll Forward]
Balance at beginning of period			(254,892)
Other comprehensive income before reclassifications			44,659
Other comprehensive income			44,659
Balance at end of period	$ (210,233)		$ (210,233)

ACCUMULATED OTHER COMPREHENSI57

ACCUMULATED OTHER COMPREHENSIVE LOSS (Amount Reclassified Out of Accumulated Other Comprehensive Loss) (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Equity [Abstract]
Reclassifications out of accumulated other comprehensive income	$ 0	$ 0	$ 0	$ 0

STOCK-BASED COMPENSATION (Narra

STOCK-BASED COMPENSATION (Narrative) (Details) - USD ($) shares in Thousands	3 Months Ended		6 Months Ended		16 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Mar. 13, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	$ 2,600,000	$ 4,300,000	$ 4,700,000	$ 6,100,000
Income tax benefit	$ 800,000	$ 600,000	$ 1,400,000	$ 1,100,000
Share repurchase program shares authorized						$ 300,000,000
Repurchases of common stock (in shares)	100	300	200	600	3,600
Repurchases of common stock	$ 5,100,000	$ 16,100,000	$ 10,134,000	$ 32,200,000	$ 187,800,000
Stock repurchase program, remaining authorized repurchase amount	112,200,000		$ 112,200,000		112,200,000
Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Repurchases of common stock (in shares)			203
Repurchases of common stock			$ 2,000
Restricted stock awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost	23,200,000		$ 23,200,000		23,200,000
Period for recognition			3 years 51 days
Fair value restricted stock	2,300,000	3,000,000	$ 6,100,000	6,200,000
Performance stock awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost	600,000		600,000		$ 600,000
Fair value restricted stock	$ 0	$ 0	$ 400,000	$ 300,000
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restriction period			3 years
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restriction period			5 years

STOCK-BASED COMPENSATION (Restr

STOCK-BASED COMPENSATION (Restricted Stock) (Details) - Restricted stock awards	6 Months Ended
	Jun. 30, 2016$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Number of shares beginning balance (in shares) | shares	362,618
Number of shares, granted (in shares) | shares	299,967
Number of shares, vested (in shares) | shares	(128,895)
Number of shares, forfeited (in shares) | shares	(16,785)
Number of shares ending balance (in shares) | shares	516,905
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Weighted average grant-date fair value beginning of period (in USD per share) | $ / shares	$ 55.79
Weighted average grant-date fair value, granted (in USD per share) | $ / shares	51.02
Weighted average grant-date fair value, vested (in USD per share) | $ / shares	55.18
Weighted average grant-date fair value, forfeited (in USD per share) | $ / shares	57.22
Weighted average grant-date fair value end of period (in USD per share) | $ / shares	$ 53.12

STOCK-BASED COMPENSATION (Perfo

STOCK-BASED COMPENSATION (Performance Stock Awards (Details) - Performance stock awards	6 Months Ended
	Jun. 30, 2016$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Number of shares beginning balance (in shares) | shares	187,274
Number of shares, granted (in shares) | shares	204,602
Number of shares, vested (in shares) | shares	(8,420)
Number of shares, forfeited (in shares) | shares	(13,676)
Number of shares ending balance (in shares) | shares	369,780
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Weighted average grant-date fair value beginning of period (in USD per share) | $ / shares	$ 57.13
Weighted average grant-date fair value, granted (in USD per share) | $ / shares	54.30
Weighted average grant-date fair value, vested (in USD per share) | $ / shares	61.90
Weighted average grant-date fair value, forfeited (in USD per share) | $ / shares	57.23
Weighted average grant-date fair value end of period (in USD per share) | $ / shares	$ 55.45

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Details) CAD in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2016USD ($)sitefacilityproceedingclaim	Dec. 31, 2012CAD	Dec. 31, 2002a	Dec. 31, 1999municipality	Dec. 31, 1968permit	Dec. 31, 2015USD ($)proceeding
Contingencies [Line Items]
Recorded reserves for actual or probable liabilities | $	$ 21,100,000					$ 21,900,000
Number of pending personal injury claims allegedly resulting from the used of Safety-Kleen's products | proceeding	62
Number of product liability claims settled or dismissed | claim	14
Legal and Administrative Proceedings
Contingencies [Line Items]
Recorded reserves for actual or probable liabilities | $	$ 18,700,000					18,900,000
Possible increase in legal and administrative proceedings | $	$ 1,800,000					1,900,000
Ville Mercier
Contingencies [Line Items]
Number of permits issued by government, for dumping organic liquid | permit					2
Number of neighboring municipalities filing separate legal proceedings against the Mercier Subsidiary and the Government of Quebec | municipality				3
General damages sought | CAD		CAD 2.9
Punitive damages sought | CAD		CAD 10
Superfund Proceedings
Contingencies [Line Items]
Number of sites owned by third party excluded from cleanup or related liabilities	129
Number of sites owned by the entity subject to proceedings under federal or state superfund laws | facility	2
Notices received from owners of third party sites seeking indemnification from the company	127
Number of sites for which environmental remediation expense is settled	32
Third party sites requiring expenditure on remediation	15
Number of sites not currently requiring expenditures on remediation	80
Number of sites which potential liability could exceed $100,000	11
Notices received from owners of third party sites seeking indemnification from the company	17
Superfund Proceedings | Minimum
Contingencies [Line Items]
Minimum potential liability | $	$ 100,000
Wichita Property
Contingencies [Line Items]
State-designated superfund site acquired, total acres | a			1,400
ChemWaste
Contingencies [Line Items]
Indemnification agreement with third party sites	11
Kleen Performance Products
Contingencies [Line Items]
Notices received from owners of third party sites seeking indemnification from the company	6
Federal and State Enforcement Actions
Contingencies [Line Items]
Recorded reserves for actual or probable liabilities | $	$ 2,400,000					$ 3,000,000
Number of pending personal injury claims allegedly resulting from the used of Safety-Kleen's products | proceeding	4					6
Federal and State Enforcement Actions | Minimum
Contingencies [Line Items]
Minimum potential liability | $	$ 100,000					$ 100,000

INCOME TAXES (Details)

INCOME TAXES (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Effective tax rates	68.70%	74.60%	(57.30%)	88.60%
Unrecognized tax benefits	$ 2.1		$ 2.1		$ 2.1
Interest on unrecognized tax benefits	0.4		0.4		$ 0.4
Decrease in unrecognized tax benefits expected in next 12 months	$ 0.5		$ 0.5

SEGMENT REPORTING (Narrative) (

SEGMENT REPORTING (Narrative) (Details)	6 Months Ended
	Jun. 30, 2016segment
Segment Reporting [Abstract]
Number of reportable segments	6

SEGMENT REPORTING (Third Party

SEGMENT REPORTING (Third Party Revenues to Direct Revenues) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Segment Reporting Information [Line Items]
Total revenues	$ 697,510	$ 936,228	$ 1,333,593	$ 1,668,727
Third party revenues
Segment Reporting Information [Line Items]
Total revenues	697,510	936,228	1,333,593	1,668,727
Intersegment revenues, net
Segment Reporting Information [Line Items]
Total revenues	0	0	0	0
Corporate Items, net
Segment Reporting Information [Line Items]
Total revenues	0	0	0	0
Direct revenues
Segment Reporting Information [Line Items]
Total revenues	697,510	936,228	1,333,593	1,668,727
Technical Services | Third party revenues
Segment Reporting Information [Line Items]
Total revenues	229,130	248,025	448,235	488,350
Technical Services | Intersegment revenues, net
Segment Reporting Information [Line Items]
Total revenues	35,578	38,314	70,422	73,218
Technical Services | Corporate Items, net
Segment Reporting Information [Line Items]
Total revenues	667	1,083	1,055	2,380
Technical Services | Direct revenues
Segment Reporting Information [Line Items]
Total revenues	265,375	287,422	519,712	563,948
Industrial and Field Services | Third party revenues
Segment Reporting Information [Line Items]
Total revenues	153,851	353,329	275,428	500,197
Industrial and Field Services | Intersegment revenues, net
Segment Reporting Information [Line Items]
Total revenues	(9,055)	(11,230)	(16,521)	(17,791)
Industrial and Field Services | Corporate Items, net
Segment Reporting Information [Line Items]
Total revenues	(286)	(401)	(303)	(323)
Industrial and Field Services | Direct revenues
Segment Reporting Information [Line Items]
Total revenues	144,510	341,698	258,604	482,083
Kleen Performance Products | Third party revenues
Segment Reporting Information [Line Items]
Total revenues	86,711	99,104	154,254	195,911
Kleen Performance Products | Intersegment revenues, net
Segment Reporting Information [Line Items]
Total revenues	(7,600)	(21,428)	(17,007)	(39,685)
Kleen Performance Products | Corporate Items, net
Segment Reporting Information [Line Items]
Total revenues	0	(1)	(1)	(2)
Kleen Performance Products | Direct revenues
Segment Reporting Information [Line Items]
Total revenues	79,111	77,675	137,246	156,224
SK Environmental Services | Third party revenues
Segment Reporting Information [Line Items]
Total revenues	191,004	175,876	370,422	336,560
SK Environmental Services | Intersegment revenues, net
Segment Reporting Information [Line Items]
Total revenues	(21,492)	(8,802)	(40,606)	(20,384)
SK Environmental Services | Corporate Items, net
Segment Reporting Information [Line Items]
Total revenues	1	3	368	3
SK Environmental Services | Direct revenues
Segment Reporting Information [Line Items]
Total revenues	169,513	167,077	330,184	316,179
Lodging Services | Third party revenues
Segment Reporting Information [Line Items]
Total revenues	16,418	21,171	32,063	55,275
Lodging Services | Intersegment revenues, net
Segment Reporting Information [Line Items]
Total revenues	137	992	401	1,156
Lodging Services | Corporate Items, net
Segment Reporting Information [Line Items]
Total revenues	14	80	35	97
Lodging Services | Direct revenues
Segment Reporting Information [Line Items]
Total revenues	16,569	22,243	32,499	56,528
Oil and Gas Field Services | Third party revenues
Segment Reporting Information [Line Items]
Total revenues	19,232	38,617	51,248	92,204
Oil and Gas Field Services | Intersegment revenues, net
Segment Reporting Information [Line Items]
Total revenues	2,432	2,154	3,311	3,486
Oil and Gas Field Services | Corporate Items, net
Segment Reporting Information [Line Items]
Total revenues	48	40	135	49
Oil and Gas Field Services | Direct revenues
Segment Reporting Information [Line Items]
Total revenues	21,712	40,811	54,694	95,739
Corporate Items | Third party revenues
Segment Reporting Information [Line Items]
Total revenues	1,164	106	1,943	230
Corporate Items | Intersegment revenues, net
Segment Reporting Information [Line Items]
Total revenues	0	0	0	0
Corporate Items | Corporate Items, net
Segment Reporting Information [Line Items]
Total revenues	(444)	(804)	(1,289)	(2,204)
Corporate Items | Direct revenues
Segment Reporting Information [Line Items]
Total revenues	$ 720	$ (698)	$ 654	$ (1,974)

SEGMENT REPORTING (Adjusted EBI

SEGMENT REPORTING (Adjusted EBITDA Information) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Segment Reporting Information [Line Items]
Adjusted EBITDA	$ 110,445	$ 163,122	$ 177,765	$ 241,399
Reconciliation to Consolidated Statements of Operations:
Accretion of environmental liabilities	2,548	2,599	5,053	5,218
Depreciation and amortization	73,393	67,773	142,295	136,129
Goodwill impairment charge	0	31,992	0	31,992
Income (loss) from operations	34,504	60,758	30,417	68,060
Other expense	189	660	539	251
Interest expense, net of interest income	21,647	19,249	40,627	38,687
Income (loss) before provision for income taxes	12,668	40,849	(10,749)	29,122
Technical Services
Segment Reporting Information [Line Items]
Adjusted EBITDA	68,891	76,808	129,289	140,209
Industrial and Field Services
Segment Reporting Information [Line Items]
Adjusted EBITDA	19,946	73,081	22,064	83,390
Kleen Performance Products
Segment Reporting Information [Line Items]
Adjusted EBITDA	9,995	15,824	14,555	11,348
SK Environmental Services
Segment Reporting Information [Line Items]
Adjusted EBITDA	45,239	41,195	80,734	68,444
Lodging Services
Segment Reporting Information [Line Items]
Adjusted EBITDA	3,022	3,852	4,041	10,762
Oil and Gas Field Services
Segment Reporting Information [Line Items]
Adjusted EBITDA	(4,207)	(2,182)	(5,601)	(779)
Corporate Items
Segment Reporting Information [Line Items]
Adjusted EBITDA	$ (32,441)	$ (45,456)	$ (67,317)	$ (71,975)

SEGMENT REPORTING (Assets by Re

SEGMENT REPORTING (Assets by Reportable Segment) (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Property, plant and equipment, net	$ 1,594,987	$ 1,532,467
Goodwill	461,491	453,105
Permits and other intangibles, net	492,224	506,818
Total assets	3,692,381	3,431,428
Technical Services
Segment Reporting Information [Line Items]
Property, plant and equipment, net	507,996	483,425
Goodwill	48,688	49,267
Permits and other intangibles, net	69,683	73,601
Total assets	823,881	800,060
Industrial and Field Services
Segment Reporting Information [Line Items]
Property, plant and equipment, net	231,334	237,660
Goodwill	106,605	105,286
Permits and other intangibles, net	13,587	14,649
Total assets	375,796	368,858
Kleen Performance Products
Segment Reporting Information [Line Items]
Property, plant and equipment, net	211,082	193,855
Goodwill	51,109	49,755
Permits and other intangibles, net	139,867	140,410
Total assets	520,943	492,483
SK Environmental Services
Segment Reporting Information [Line Items]
Property, plant and equipment, net	302,260	264,539
Goodwill	220,824	216,589
Permits and other intangibles, net	251,087	256,251
Total assets	852,082	805,488
Lodging Services
Segment Reporting Information [Line Items]
Property, plant and equipment, net	104,386	105,208
Goodwill	34,265	32,208
Permits and other intangibles, net	6,495	7,045
Total assets	181,031	181,357
Oil and Gas Field Services
Segment Reporting Information [Line Items]
Property, plant and equipment, net	146,423	156,286
Goodwill	0	0
Permits and other intangibles, net	11,505	14,862
Total assets	235,775	244,210
Corporate Items
Segment Reporting Information [Line Items]
Property, plant and equipment, net	91,506	91,494
Goodwill	0	0
Permits and other intangibles, net	0	0
Total assets	$ 702,873	$ 538,972

SEGMENT REPORTING (Total Assets

SEGMENT REPORTING (Total Assets by Geographical Area) (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Revenues from External Customers and Long-Lived Assets [Line Items]
Total assets	$ 3,692,381	$ 3,431,428
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Total assets	2,837,201	2,575,746
Canada
Revenues from External Customers and Long-Lived Assets [Line Items]
Total assets	850,355	851,949
Other foreign
Revenues from External Customers and Long-Lived Assets [Line Items]
Total assets	$ 4,825	$ 3,733

GUARANTOR AND NON-GUARANTOR S68

GUARANTOR AND NON-GUARANTOR SUBSIDIARIES FINANCIAL INFORMATION (Narrative) (Details) - USD ($)	6 Months Ended
	Jun. 30, 2016	Mar. 14, 2016	Dec. 07, 2012
Guarantor and Non-Guarantor Subsidiaries Financial Information [Abstract]
Subsidiary or equity method investee, cumulative percentage ownership after all transactions	100.00%
Senior unsecured notes, at 5.125%, due June 1, 2021 (2021 Notes) | Unsecured debt
Debt Instrument [Line Items]
Issuance of debt	$ 250,000,000	$ 250,000,000	$ 600,000,000

GUARANTOR AND NON-GUARANTOR S69

GUARANTOR AND NON-GUARANTOR SUBSIDIARIES FINANCIAL INFORMATION (Condensed Consolidating Balance Sheets) (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2015	Dec. 31, 2014
ASSETS
Cash and cash equivalents	$ 352,923	$ 184,708	$ 173,621	$ 246,879
Intercompany receivables	0	0
Accounts receivable, net	503,749	496,004
Other current assets	262,462	240,484
Property, plant and equipment, net	1,594,987	1,532,467
Investments in subsidiaries	0	0
Intercompany debt receivable	0	0
Goodwill	461,491	453,105
Permits and other intangibles, net	492,224	506,818
Other long-term assets	24,545	17,842
Total assets	3,692,381	3,431,428
LIABILITIES AND STOCKHOLDERS' EQUITY
Current liabilities	520,421	517,120
Intercompany payables	0	0
Closure, post-closure and remedial liabilities, net	165,434	167,846
Long-term obligations	1,631,881	1,382,543
Intercompany debt payable	0	0
Other long-term liabilities	258,302	267,637
Total liabilities	2,576,038	2,335,146
Stockholders’ equity	1,116,343	1,096,282
Total liabilities and stockholders’ equity	3,692,381	3,431,428
Reportable Legal Entities | Clean Harbors, Inc.
ASSETS
Cash and cash equivalents	51,291	11,017	4,208	1,006
Intercompany receivables	181,741	164,709
Accounts receivable, net	0	0
Other current assets	378	0
Property, plant and equipment, net	0	0
Investments in subsidiaries	2,833,394	2,547,307
Intercompany debt receivable	0	0
Goodwill	0	0
Permits and other intangibles, net	0	0
Other long-term assets	1,412	1,068
Total assets	3,068,216	2,724,101
LIABILITIES AND STOCKHOLDERS' EQUITY
Current liabilities	21,852	20,813
Intercompany payables	294,439	220,762
Closure, post-closure and remedial liabilities, net	0	0
Long-term obligations	1,631,881	1,382,543
Intercompany debt payable	3,701	3,701
Other long-term liabilities	0	0
Total liabilities	1,951,873	1,627,819
Stockholders’ equity	1,116,343	1,096,282
Total liabilities and stockholders’ equity	3,068,216	2,724,101
Reportable Legal Entities | U.S. Guarantor Subsidiaries
ASSETS
Cash and cash equivalents	224,493	83,479	80,577	154,147
Intercompany receivables	302,354	213,243
Accounts receivable, net	407,601	404,580
Other current assets	198,612	179,969
Property, plant and equipment, net	1,138,285	1,082,466
Investments in subsidiaries	514,708	522,067
Intercompany debt receivable	277,623	260,957
Goodwill	369,978	367,306
Permits and other intangibles, net	423,932	435,080
Other long-term assets	9,559	10,274
Total assets	3,867,145	3,559,421
LIABILITIES AND STOCKHOLDERS' EQUITY
Current liabilities	427,367	424,588
Intercompany payables	217,430	195,287
Closure, post-closure and remedial liabilities, net	150,182	153,190
Long-term obligations	0	0
Intercompany debt payable	0	0
Other long-term liabilities	238,772	239,049
Total liabilities	1,033,751	1,012,114
Stockholders’ equity	2,833,394	2,547,307
Total liabilities and stockholders’ equity	3,867,145	3,559,421
Reportable Legal Entities | Foreign Non-Guarantor Subsidiaries
ASSETS
Cash and cash equivalents	77,139	90,212	88,836	91,726
Intercompany receivables	30,741	39,804
Accounts receivable, net	96,148	91,424
Other current assets	63,472	60,515
Property, plant and equipment, net	456,702	450,001
Investments in subsidiaries	0	0
Intercompany debt receivable	3,701	3,701
Goodwill	91,513	85,799
Permits and other intangibles, net	68,292	71,738
Other long-term assets	13,574	6,500
Total assets	901,282	899,694
LIABILITIES AND STOCKHOLDERS' EQUITY
Current liabilities	71,202	71,719
Intercompany payables	2,967	1,707
Closure, post-closure and remedial liabilities, net	15,252	14,656
Long-term obligations	0	0
Intercompany debt payable	277,623	260,957
Other long-term liabilities	19,530	28,588
Total liabilities	386,574	377,627
Stockholders’ equity	514,708	522,067
Total liabilities and stockholders’ equity	901,282	899,694
Consolidating Adjustments
ASSETS
Cash and cash equivalents	0	0	$ 0	$ 0
Intercompany receivables	(514,836)	(417,756)
Accounts receivable, net	0	0
Other current assets	0	0
Property, plant and equipment, net	0	0
Investments in subsidiaries	(3,348,102)	(3,069,374)
Intercompany debt receivable	(281,324)	(264,658)
Goodwill	0	0
Permits and other intangibles, net	0	0
Other long-term assets	0	0
Total assets	(4,144,262)	(3,751,788)
LIABILITIES AND STOCKHOLDERS' EQUITY
Current liabilities	0	0
Intercompany payables	(514,836)	(417,756)
Closure, post-closure and remedial liabilities, net	0	0
Long-term obligations	0	0
Intercompany debt payable	(281,324)	(264,658)
Other long-term liabilities	0	0
Total liabilities	(796,160)	(682,414)
Stockholders’ equity	(3,348,102)	(3,069,374)
Total liabilities and stockholders’ equity	$ (4,144,262)	$ (3,751,788)

GUARANTOR AND NON-GUARANTOR S70

GUARANTOR AND NON-GUARANTOR SUBSIDIARIES FINANCIAL INFORMATION (Consolidating Statement of Operations) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Revenues:
Service revenues	$ 584,562	$ 801,347	$ 1,114,793	$ 1,397,677
Product revenues	112,948	134,881	218,800	271,050
Total revenues	697,510	936,228	1,333,593	1,668,727
Cost of revenues (exclusive of items shown separately below)
Service cost of revenues	388,684	544,870	762,670	961,260
Product cost of revenues	91,318	107,818	181,611	237,935
Total cost of revenues	480,002	652,688	944,281	1,199,195
Selling, general and administrative expenses	107,063	120,418	211,547	228,133
Accretion of environmental liabilities	2,548	2,599	5,053	5,218
Depreciation and amortization	73,393	67,773	142,295	136,129
Goodwill impairment charge	0	31,992	0	31,992
Income (loss) from operations	34,504	60,758	30,417	68,060
Other income (expense)	(189)	(660)	(539)	(251)
Interest (expense) income	(21,647)	(19,249)	(40,627)	(38,687)
Equity in earnings of subsidiaries, net of taxes	0	0	0	0
Intercompany interest income (expense)	0	0	0	0
Income (loss) before provision for income taxes	12,668	40,849	(10,749)	29,122
(Benefit) provision for income taxes	8,702	30,454	6,156	25,816
Net income (loss)	3,966	10,395	(16,905)	3,306
Other comprehensive (loss) income	(1,178)	12,231	44,659	(65,172)
Comprehensive income (loss)	2,788	22,626	27,754	(61,866)
Reportable Legal Entities | Clean Harbors, Inc.
Revenues:
Service revenues	0	0	0	0
Product revenues	0	0	0	0
Total revenues	0	0	0	0
Cost of revenues (exclusive of items shown separately below)
Service cost of revenues	(587)	0	(587)	0
Product cost of revenues	0	0	0	0
Total cost of revenues	(587)	0	(587)	0
Selling, general and administrative expenses	37	25	61	50
Accretion of environmental liabilities	0	0	0	0
Depreciation and amortization	0	0	0	0
Goodwill impairment charge		0		0
Income (loss) from operations	550	(25)	526	(50)
Other income (expense)	0	0	0	0
Interest (expense) income	(22,962)	(19,652)	(43,105)	(39,291)
Equity in earnings of subsidiaries, net of taxes	17,413	22,201	8,642	26,910
Intercompany interest income (expense)	0	0	0	0
Income (loss) before provision for income taxes	(4,999)	2,524	(33,937)	(12,431)
(Benefit) provision for income taxes	(8,965)	(7,871)	(17,032)	(15,737)
Net income (loss)	3,966	10,395	(16,905)	3,306
Other comprehensive (loss) income	(1,178)	12,231	44,659	(65,172)
Comprehensive income (loss)	2,788	22,626	27,754	(61,866)
Reportable Legal Entities | U.S. Guarantor Subsidiaries
Revenues:
Service revenues	456,013	628,408	884,490	1,046,925
Product revenues	95,648	115,335	185,236	231,871
Total revenues	551,661	743,743	1,069,726	1,278,796
Cost of revenues (exclusive of items shown separately below)
Service cost of revenues	292,343	415,111	575,307	692,713
Product cost of revenues	79,108	98,258	158,462	213,544
Total cost of revenues	371,451	513,369	733,769	906,257
Selling, general and administrative expenses	83,882	93,677	164,537	174,661
Accretion of environmental liabilities	2,313	2,287	4,603	4,593
Depreciation and amortization	50,696	44,602	99,391	90,403
Goodwill impairment charge		4,164		4,164
Income (loss) from operations	43,319	85,644	67,426	98,718
Other income (expense)	400	168	312	279
Interest (expense) income	1,284	324	2,395	502
Equity in earnings of subsidiaries, net of taxes	(9,195)	(29,550)	(35,690)	(36,579)
Intercompany interest income (expense)	5,497	6,036	10,656	12,013
Income (loss) before provision for income taxes	41,305	62,622	45,099	74,933
(Benefit) provision for income taxes	23,892	40,421	36,457	48,023
Net income (loss)	17,413	22,201	8,642	26,910
Other comprehensive (loss) income	(1,178)	12,231	44,659	(65,172)
Comprehensive income (loss)	16,235	34,432	53,301	(38,262)
Reportable Legal Entities | Foreign Non-Guarantor Subsidiaries
Revenues:
Service revenues	139,413	190,657	253,436	384,110
Product revenues	19,391	22,444	38,104	45,648
Total revenues	158,804	213,101	291,540	429,758
Cost of revenues (exclusive of items shown separately below)
Service cost of revenues	107,792	147,477	211,083	301,905
Product cost of revenues	14,301	12,458	27,689	30,860
Total cost of revenues	122,093	159,935	238,772	332,765
Selling, general and administrative expenses	23,144	26,716	46,949	53,422
Accretion of environmental liabilities	235	312	450	625
Depreciation and amortization	22,697	23,171	42,904	45,726
Goodwill impairment charge		27,828		27,828
Income (loss) from operations	(9,365)	(24,861)	(37,535)	(30,608)
Other income (expense)	(589)	(828)	(851)	(530)
Interest (expense) income	31	79	83	102
Equity in earnings of subsidiaries, net of taxes	0	0	0	0
Intercompany interest income (expense)	(5,497)	(6,036)	(10,656)	(12,013)
Income (loss) before provision for income taxes	(15,420)	(31,646)	(48,959)	(43,049)
(Benefit) provision for income taxes	(6,225)	(2,096)	(13,269)	(6,470)
Net income (loss)	(9,195)	(29,550)	(35,690)	(36,579)
Other comprehensive (loss) income	(597)	8,061	28,330	(42,574)
Comprehensive income (loss)	(9,792)	(21,489)	(7,360)	(79,153)
Consolidating Adjustments
Revenues:
Service revenues	(10,864)	(17,718)	(23,133)	(33,358)
Product revenues	(2,091)	(2,898)	(4,540)	(6,469)
Total revenues	(12,955)	(20,616)	(27,673)	(39,827)
Cost of revenues (exclusive of items shown separately below)
Service cost of revenues	(10,864)	(17,718)	(23,133)	(33,358)
Product cost of revenues	(2,091)	(2,898)	(4,540)	(6,469)
Total cost of revenues	(12,955)	(20,616)	(27,673)	(39,827)
Selling, general and administrative expenses	0	0	0	0
Accretion of environmental liabilities	0	0	0	0
Depreciation and amortization	0	0	0	0
Goodwill impairment charge		0		0
Income (loss) from operations	0	0	0	0
Other income (expense)	0	0	0	0
Interest (expense) income	0	0	0	0
Equity in earnings of subsidiaries, net of taxes	(8,218)	7,349	27,048	9,669
Intercompany interest income (expense)	0	0	0	0
Income (loss) before provision for income taxes	(8,218)	7,349	27,048	9,669
(Benefit) provision for income taxes	0	0	0	0
Net income (loss)	(8,218)	7,349	27,048	9,669
Other comprehensive (loss) income	1,775	(20,292)	(72,989)	107,746
Comprehensive income (loss)	$ (6,443)	$ (12,943)	$ (45,941)	$ 117,415

GUARANTOR AND NON-GUARANTOR S71

GUARANTOR AND NON-GUARANTOR SUBSIDIARIES FINANCIAL INFORMATION (Condensed Consolidating Statements of Cash Flows) (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Condensed consolidating statement of cash flows
Net cash from (used in) operating activities	$ 120,051	$ 193,815
Cash flows used in investing activities:
Additions to property, plant and equipment	(123,529)	(124,145)
Proceeds from sales of fixed assets	2,668	2,646
Acquisitions, net of cash acquired	(58,989)	(79,610)
Costs to obtain or renew permits	(973)	(3,088)
Purchases of available-for-sale securities	(598)	0
Investment in subsidiaries	0
Intercompany	0	0
Net cash used in investing activities	(181,421)	(204,197)
Cash flows from (used in) financing activities:
Change in uncashed checks	(11,022)	(22,160)
Exercise of stock options	184	397
Issuance of restricted shares, net of shares remitted	(1,879)	(1,837)
Repurchases of common stock	(10,134)	(32,203)
Excess tax benefit of stock-based compensation	2	102
Deferred financing costs paid	(2,614)	0
Payments of capital leases	0	(471)
Issuance of senior secured notes, including premium	250,625
Intercompany	0	0
Net cash from (used in) financing activities	225,162	(56,172)
Effect of exchange rate change on cash	4,423	(6,704)
Increase (decrease) in cash and cash equivalents	168,215	(73,258)
Cash and cash equivalents, beginning of period	184,708	246,879
Cash and cash equivalents, end of period	352,923	173,621
Consolidating Adjustments
Condensed consolidating statement of cash flows
Net cash from (used in) operating activities	0	0
Cash flows used in investing activities:
Additions to property, plant and equipment	0	0
Proceeds from sales of fixed assets	0	0
Acquisitions, net of cash acquired	0	0
Costs to obtain or renew permits	0	0
Purchases of available-for-sale securities	0
Investment in subsidiaries	250,625
Intercompany	11,827	31,830
Net cash used in investing activities	262,452	31,830
Cash flows from (used in) financing activities:
Change in uncashed checks	0	0
Exercise of stock options	0	0
Issuance of restricted shares, net of shares remitted	0	0
Repurchases of common stock	0	0
Excess tax benefit of stock-based compensation	0	0
Deferred financing costs paid	0
Payments of capital leases		0
Issuance of senior secured notes, including premium	(250,625)
Intercompany	(11,827)	(31,830)
Net cash from (used in) financing activities	(262,452)	(31,830)
Effect of exchange rate change on cash	0	0
Increase (decrease) in cash and cash equivalents	0	0
Cash and cash equivalents, beginning of period	0	0
Cash and cash equivalents, end of period	0	0
Clean Harbors, Inc. | Reportable Legal Entities
Condensed consolidating statement of cash flows
Net cash from (used in) operating activities	42,990	4,913
Cash flows used in investing activities:
Additions to property, plant and equipment	0	0
Proceeds from sales of fixed assets	0	0
Acquisitions, net of cash acquired	0	0
Costs to obtain or renew permits	0	0
Purchases of available-for-sale securities	(102)
Investment in subsidiaries	(250,625)
Intercompany	0	0
Net cash used in investing activities	(250,727)	0
Cash flows from (used in) financing activities:
Change in uncashed checks	0	0
Exercise of stock options	184	397
Issuance of restricted shares, net of shares remitted	(1,879)	(1,837)
Repurchases of common stock	(10,134)	(32,203)
Excess tax benefit of stock-based compensation	2	102
Deferred financing costs paid	(2,614)
Payments of capital leases		0
Issuance of senior secured notes, including premium	250,625
Intercompany	11,827	31,830
Net cash from (used in) financing activities	248,011	(1,711)
Effect of exchange rate change on cash	0	0
Increase (decrease) in cash and cash equivalents	40,274	3,202
Cash and cash equivalents, beginning of period	11,017	1,006
Cash and cash equivalents, end of period	51,291	4,208
U.S. Guarantor Subsidiaries | Reportable Legal Entities
Condensed consolidating statement of cash flows
Net cash from (used in) operating activities	65,860	158,241
Cash flows used in investing activities:
Additions to property, plant and equipment	(105,175)	(104,068)
Proceeds from sales of fixed assets	694	368
Acquisitions, net of cash acquired	(48,989)	(79,610)
Costs to obtain or renew permits	(908)	(4)
Purchases of available-for-sale securities	0
Investment in subsidiaries	0
Intercompany	(11,827)	(31,830)
Net cash used in investing activities	(166,205)	(215,144)
Cash flows from (used in) financing activities:
Change in uncashed checks	(9,266)	(16,474)
Exercise of stock options	0	0
Issuance of restricted shares, net of shares remitted	0	0
Repurchases of common stock	0	0
Excess tax benefit of stock-based compensation	0	0
Deferred financing costs paid	0
Payments of capital leases		(193)
Issuance of senior secured notes, including premium	250,625
Intercompany	0	0
Net cash from (used in) financing activities	241,359	(16,667)
Effect of exchange rate change on cash	0	0
Increase (decrease) in cash and cash equivalents	141,014	(73,570)
Cash and cash equivalents, beginning of period	83,479	154,147
Cash and cash equivalents, end of period	224,493	80,577
Foreign Non-Guarantor Subsidiaries | Reportable Legal Entities
Condensed consolidating statement of cash flows
Net cash from (used in) operating activities	11,201	30,661
Cash flows used in investing activities:
Additions to property, plant and equipment	(18,354)	(20,077)
Proceeds from sales of fixed assets	1,974	2,278
Acquisitions, net of cash acquired	(10,000)	0
Costs to obtain or renew permits	(65)	(3,084)
Purchases of available-for-sale securities	(496)
Investment in subsidiaries	0
Intercompany	0	0
Net cash used in investing activities	(26,941)	(20,883)
Cash flows from (used in) financing activities:
Change in uncashed checks	(1,756)	(5,686)
Exercise of stock options	0	0
Issuance of restricted shares, net of shares remitted	0	0
Repurchases of common stock	0	0
Excess tax benefit of stock-based compensation	0	0
Deferred financing costs paid	0
Payments of capital leases		(278)
Issuance of senior secured notes, including premium	0
Intercompany	0	0
Net cash from (used in) financing activities	(1,756)	(5,964)
Effect of exchange rate change on cash	4,423	(6,704)
Increase (decrease) in cash and cash equivalents	(13,073)	(2,890)
Cash and cash equivalents, beginning of period	90,212	91,726
Cash and cash equivalents, end of period	$ 77,139	$ 88,836

SUBSEQUENT EVENTS Narrative (De

SUBSEQUENT EVENTS Narrative (Details) - Subsequent Event $ in Millions	1 Months Ended		3 Months Ended
	Aug. 31, 2016USD ($)aquisition	Jul. 31, 2016USD ($)aquisition	Sep. 30, 2016USD ($)
Subsequent Event [Line Items]
Number of acquisitions | aquisition		2
Payments to acquire business | $		$ 101
Forecast
Subsequent Event [Line Items]
Number of acquisitions | aquisition	3
Purchase price | $	$ 50		$ 50