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CLH Clean Harbors

Cover

Cover - shares3 Months Ended
Mar. 31, 2021Apr. 30, 2021
Cover [Abstract]
Document Type10-Q
Document Quarterly Reporttrue
Document Period End DateMar. 31,
2021
Document Transition Reportfalse
Entity File Number001-34223
Entity Registrant NameCLEAN HARBORS, INC
Entity Incorporation, State or Country CodeMA
Entity Tax Identification Number04-2997780
Entity Address, Address Line One42 Longwater Drive
Entity Address, City or TownNorwell
Entity Address, State or ProvinceMA
Entity Address, Postal Zip Code02061-9149
City Area Code781
Local Phone Number792-5000
Title of 12(b) SecurityCommon Stock, $0.01 par value
Trading SymbolCLH
Security Exchange NameNYSE
Entity Current Reporting StatusYes
Entity Interactive Data CurrentYes
Entity Filer CategoryLarge Accelerated Filer
Entity Small Businessfalse
Entity Emerging Growth Companyfalse
Entity Shell Companyfalse
Entity Common Stock, Shares Outstanding54,564,897
Entity Central Index Key0000822818
Current Fiscal Year End Date--12-31
Document Fiscal Year Focus2021
Document Fiscal Period FocusQ1
Amendment Flagfalse

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in ThousandsMar. 31, 2021Dec. 31, 2020
Current assets:
Cash and cash equivalents $ 496,383 $ 519,101
Short-term marketable securities74,320 51,857
Accounts receivable, net of allowances aggregating $44,407 and $44,749, respectively620,184 611,534
Unbilled accounts receivable55,239 55,681
Inventories and supplies219,499 220,498
Prepaid expenses and other current assets76,726 67,051
Total current assets1,542,351 1,525,722
Property, plant and equipment, net1,527,944 1,525,298
Other assets:
Operating lease right-of-use assets142,006 150,341
Goodwill543,605 527,023
Permits and other intangibles, net380,053 386,620
Other16,580 16,516
Total other assets1,082,244 1,080,500
Total assets4,152,539 4,131,520
Current liabilities:
Current portion of long-term debt7,535 7,535
Accounts payable213,355 195,878
Deferred revenue83,165 74,066
Accrued expenses284,212 295,823
Current portion of closure, post-closure and remedial liabilities26,896 26,093
Current portion of operating lease liabilities35,390 36,750
Total current liabilities650,553 636,145
Other liabilities:
Closure and post-closure liabilities, less current portion of $11,887 and $13,903, respectively79,218 74,023
Remedial liabilities, less current portion of $15,009 and $12,190, respectively99,239 102,623
Long-term debt, less current portion1,548,517 1,549,641
Operating lease liabilities, less current portion107,554 114,258
Deferred tax liabilities230,236 230,097
Other long-term liabilities88,772 83,182
Total other liabilities2,153,536 2,153,824
Commitments and contingent liabilities (See Note 16)
Stockholders’ equity:
Common stock, $0.01 par value: authorized 80,000,000 shares; issued and outstanding 54,550,817 and 54,772,696 shares, respectively546 548
Additional paid-in capital555,966 582,749
Accumulated other comprehensive loss(199,529)(211,477)
Accumulated earnings991,467 969,731
Total stockholders’ equity1,348,450 1,341,551
Total liabilities and stockholders’ equity $ 4,152,539 $ 4,131,520

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in ThousandsMar. 31, 2021Dec. 31, 2020
Statement of Financial Position [Abstract]
Account receivable, allowances aggregating $ 44,407 $ 44,749
Closure and post-closure liabilities, current portion11,887 13,903
Remedial liabilities, current portion $ 15,009 $ 12,190
Common stock, par value (in dollars per share) $ 0.01 $ 0.01
Common stock, authorized shares (in shares)80,000,000 80,000,000
Common stock, issued shares (in shares)54,550,817 54,772,696
Common stock, outstanding shares (in shares)54,550,817 54,772,696

UNAUDITED CONSOLIDATED STATEMEN

UNAUDITED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands3 Months Ended
Mar. 31, 2021Mar. 31, 2020
Revenues:
Total revenues $ 808,148 $ 858,563
Cost of revenues: (exclusive of items shown separately below)
Total cost of revenues560,536 606,666
Selling, general and administrative expenses121,641 129,307
Accretion of environmental liabilities2,953 2,561
Depreciation and amortization72,163 74,533
Income from operations50,855 45,496
Other expense, net(1,228)(2,365)
Loss on sale of businesses0 (3,074)
Interest expense, net of interest income of $479 and $998, respectively(17,918)(18,787)
Income before provision for income taxes31,709 21,270
Provision for income taxes9,973 9,698
Net income $ 21,736 $ 11,572
Earnings Per Share [Abstract]
Basic (in dollars per share) $ 0.40 $ 0.21
Diluted (in dollars per share) $ 0.39 $ 0.21
Shares used to compute earnings per share - Basic (in shares)54,723 55,757
Shares used to compute earnings per share - Diluted (in shares)55,043 56,055
Service revenues
Revenues:
Total revenues $ 662,708 $ 719,867
Cost of revenues: (exclusive of items shown separately below)
Total cost of revenues450,338 492,716
Product revenues
Revenues:
Total revenues145,440 138,696
Cost of revenues: (exclusive of items shown separately below)
Total cost of revenues $ 110,198 $ 113,950

UNAUDITED CONSOLIDATED STATEM_2

UNAUDITED CONSOLIDATED STATEMENTS OF OPERATIONS (Parenthetical) - USD ($) $ in Thousands3 Months Ended
Mar. 31, 2021Mar. 31, 2020
Income Statement [Abstract]
Interest income $ 479 $ 998

UNAUDITED CONSOLIDATED STATEM_3

UNAUDITED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands3 Months Ended
Mar. 31, 2021Mar. 31, 2020
Statement of Comprehensive Income [Abstract]
Net income $ 21,736 $ 11,572
Other comprehensive income (loss), net of tax:
Unrealized losses on available-for-sale securities(74)(64)
Unrealized gain (loss) on interest rate hedge3,108 (18,382)
Reclassification adjustment for losses on interest rate hedge included in net income2,448 1,098
Foreign currency translation adjustments6,466 (41,958)
Other comprehensive income (loss), net of tax11,948 (59,306)
Comprehensive income (loss) $ 33,684 $ (47,734)

UNAUDITED CONSOLIDATED STATEM_4

UNAUDITED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands3 Months Ended
Mar. 31, 2021Mar. 31, 2020
Cash flows from operating activities:
Net income $ 21,736 $ 11,572
Adjustments to reconcile net income to net cash from operating activities:
Depreciation and amortization72,163 74,533
Allowance for doubtful accounts2,446 4,700
Amortization of deferred financing costs and debt discount900 891
Accretion of environmental liabilities2,953 2,561
Changes in environmental liability estimates275 3,470
Deferred income taxes(39)0
Other expense, net1,228 2,365
Stock-based compensation3,480 3,291
Loss on sale of businesses0 3,074
Environmental expenditures(3,011)(3,435)
Changes in assets and liabilities, net of acquisitions:
Accounts receivable and unbilled accounts receivable(9,703)(24,960)
Inventories and supplies(747)(7,024)
Other current and non-current assets(9,956)8,714
Accounts payable22,179 (5,169)
Other current and long-term liabilities(904)(40,902)
Net cash from operating activities103,000 33,681
Cash flows used in investing activities:
Additions to property, plant and equipment(41,913)(82,767)
Proceeds from sale and disposal of fixed assets1,204 2,150
Acquisitions, net of cash acquired(22,918)0
Proceeds from sale of businesses, net of transactional costs0 7,856
Additions to intangible assets including costs to obtain or renew permits(505)(448)
Proceeds from sale of available-for-sale securities20,375 12,180
Purchases of available-for-sale securities(42,980)(32,058)
Net cash used in investing activities(86,737)(93,087)
Cash flows (used in) from financing activities:
Change in uncashed checks(6,662)(1,775)
Tax payments related to withholdings on vested restricted stock(3,719)(2,224)
Repurchases of common stock(26,546)(17,341)
Deferred financing costs paid(137)0
Payments on finance leases(1,672)(329)
Principal payments on debt(1,884)(1,884)
Borrowings from revolving credit facility0 150,000
Net cash (used in) from financing activities(40,620)126,447
Effect of exchange rate change on cash1,639 (6,827)
(Decrease) increase in cash and cash equivalents(22,718)60,214
Cash and cash equivalents, beginning of period519,101 371,991
Cash and cash equivalents, end of period496,383 432,205
Cash payments for interest and income taxes:
Interest paid27,507 30,648
Income taxes paid, net of refunds3,599 971
Non-cash investing activities:
Property, plant and equipment accrued5,108 12,173
ROU assets obtained in exchange for operating lease liabilities2,305 12,410
ROU assets obtained in exchange for finance lease liabilities $ 9,205 $ (856)

UNAUDITED CONSOLIDATED STATEM_5

UNAUDITED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in ThousandsTotalCommon StockAdditional Paid-in CapitalAccumulated Other Comprehensive LossAccumulated Earnings
Balance beginning of period (in shares) at Dec. 31, 201955,798
Balance beginning of period at Dec. 31, 2019 $ 1,269,813 $ 558 $ 644,412 $ (210,051) $ 834,894
Increase (Decrease) in Stockholders' Equity
Net income11,572 11,572
Other comprehensive (loss) income(59,306)(59,306)
Stock-based compensation3,291 3,291
Issuance of common stock for restricted share vesting, net of employee tax withholdings (in shares)59
Issuance of common stock for restricted share vesting, net of employee tax withholdings(2,224) $ 1 (2,225)
Repurchases of common stock (in shares)(302)
Repurchases of common stock(17,341) $ (3)(17,338)
Balance ending of period (in shares) at Mar. 31, 202055,555
Balance ending of period at Mar. 31, 20201,205,805 $ 556 628,140 (269,357)846,466
Balance beginning of period (in shares) at Dec. 31, 202054,773
Balance beginning of period at Dec. 31, 20201,341,551 $ 548 582,749 (211,477)969,731
Increase (Decrease) in Stockholders' Equity
Net income21,736 21,736
Other comprehensive (loss) income11,948 11,948
Stock-based compensation3,480 3,480
Issuance of common stock for restricted share vesting, net of employee tax withholdings (in shares)78
Issuance of common stock for restricted share vesting, net of employee tax withholdings(3,719) $ 1 (3,720)
Repurchases of common stock (in shares)(300)
Repurchases of common stock(26,546) $ (3)(26,543)
Balance ending of period (in shares) at Mar. 31, 202154,551
Balance ending of period at Mar. 31, 2021 $ 1,348,450 $ 546 $ 555,966 $ (199,529) $ 991,467

UNAUDITED CONSOLIDATED STATEM_6

UNAUDITED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (PARENTHETICAL) - $ / sharesMar. 31, 2021Dec. 31, 2020
Statement of Stockholders' Equity [Abstract]
Common stock, par value (in dollars per share) $ 0.01 $ 0.01

BASIS OF PRESENTATION

BASIS OF PRESENTATION3 Months Ended
Mar. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
BASIS OF PRESENTATIONBASIS OF PRESENTATIONThe 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 and are 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 conjunction with the financial statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2020.

SIGNIFICANT ACCOUNTING POLICIES

SIGNIFICANT ACCOUNTING POLICIES3 Months Ended
Mar. 31, 2021
Accounting Policies [Abstract]
SIGNIFICANT ACCOUNTING POLICIESSIGNIFICANT 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, 2020. There have been no material changes in these policies or their application except for the changes described below. Changes in Operating Segments During the first quarter of 2021, the Company reorganized its Safety-Kleen business. The collection services for waste oil, used oil filters, antifreeze and related items and bulk blended oil sales operations were combined with the Safety-Kleen Oil business to form the Safety-Kleen Sustainability Solutions business. Under this structure, Safety-Kleen Sustainability Solutions will encompass both sides of the spread the Company manages in its re-refinery business, and the Company expects this change to drive additional growth in its sustainable lubricant products and related services. Concurrently with this change, the Company consolidated the Safety-Kleen branches' core offerings, including containerized waste, parts washer and vacuum services, into the legacy Clean Harbors Environmental Services sales and service operations. The Company expects this change to foster enhanced cross-selling opportunities within the environmental businesses and increase market presence with small quantity generators of hazardous waste. In restructuring the operations of the Company in this manner, the information that the chief operating decision maker regularly reviews for purposes of allocating resources and assessing performance changed to conform to this new operating structure of the business and the Company reevaluated the identification of its operating segments. In accordance with ASC 280, Segment Reporting, Environmental Services and Safety-Kleen Sustainability Solutions are the Company's operating segments and reportable segments starting in the first quarter of 2021,

REVENUES

REVENUES3 Months Ended
Mar. 31, 2021
Revenue from Contract with Customer [Abstract]
REVENUESREVENUES The Company generates revenues through its Environmental Services and Safety-Kleen Sustainability Solutions operating segments. The Company's Environmental Services operating segment generally has four sources of revenue and the Safety-Kleen Sustainability Solutions operating segment has two sources of revenue. Technical Services —Technical Services contribute to the revenues of the Environmental Services operating segment. These services are generated from fees charged for waste material management and disposal services including onsite environmental management services, collection and transportation, packaging, recycling, treatment and disposal of waste. Revenue is primarily generated by short-term projects, most of which are governed by master service agreements that are long-term in nature. These master service agreements are typically entered into with the Company's larger customers and outline the pricing and legal frameworks for such arrangements. Services are provided based on purchase orders or agreements with the customer and include prices based upon units of volume of waste and transportation and other fees. Collection and transportation revenues are recognized over time, as the customer receives and consumes the benefits of the services as they are being performed and the Company has a right to payment for performance completed to date. The Company uses the input method to recognize revenue over time, based on time and materials incurred. Revenues for treatment and disposal of waste are recognized upon completion of treatment, final disposition in a landfill or incineration, or when the waste is shipped to a third party for processing and disposal. The Company periodically enters into bundled arrangements for the collection and transportation and disposal of waste. For such arrangements, transportation and disposal are considered distinct performance obligations and the Company allocates revenue to each based on the relative standalone selling price (i.e., the estimated price that a customer would pay for the services on a standalone basis). Revenues from waste that is not yet completely processed and disposed and the related costs are deferred. The deferred revenues and costs are recognized when the related services are completed. The period between collection and transportation and the final processing and disposal ranges depending on the location of the customer, but generally is measured in days. Field and Emergency Response Services —Field and Emergency Response Services contribute to the revenues of the Environmental Services operating segment. Field Services revenues are generated from cleanup services at customer sites, including municipalities and utilities, or other locations on a scheduled or emergency response basis. Services include confined space entry for tank cleaning, site decontamination, large remediation projects, demolition, spill cleanup on land and water, railcar cleaning, product recovery and transfer and vacuum services. Additional services include filtration and water treatment services. Response services for environmental, contamination or pandemic related emergencies include any scale from man-made disasters such as oil spills to natural disasters such as hurricanes. More recently demand has increased for projects involving contagion disinfection, decontamination and disposal services in response to the COVID-19 pandemic. Field and emergency response services are provided based on purchase orders or agreements with customers and include prices generally based upon daily, hourly or job rates for equipment, materials and personnel. The Company recognizes revenue for these services over time, as the customer receives and consumes the benefits of the service as they are being performed and the Company has a right to payment for performance completed to date. The Company uses the input method to recognize revenue over time, based on time and materials incurred. The duration of such services can be over a number of hours, several days or even months for larger scale projects. Industrial Services and Other —Industrial Services contribute to the revenues of the Environmental Services operating segment. These revenues are primarily generated from industrial and specialty services provided to refineries, mines, upgraders, chemical plants, pulp and paper mills, manufacturing facilities, power generation facilities and other industrial customers throughout North America. Services include in-plant cleaning and maintenance services, plant outage and turnaround services, specialty cleaning services including chemical cleaning and high and ultra-high pressure water cleaning, daylighting, production services and upstream energy services. Services are provided based on purchase orders or agreements with the customer and include prices based upon daily, hourly or job rates for equipment, materials and personnel. The Company recognizes revenue for these services over time, as the customer receives and consumes the benefits of the services as they are being performed and the Company has a right to payment for performance completed to date. The Company uses the input method to recognize revenue over time, based on time and materials incurred. Safety-Kleen Environmental Services —Safety-Kleen Environmental Services revenues contribute both to the Environmental Services operating segment and the Safety-Kleen Sustainability Solutions operating segment depending upon the nature of such revenues and operating responsibilities relative to driving these revenues. Revenues from providing containerized waste handling and disposal services, parts washer services and vacuum services, referred to collectively as the Safety-Kleen Environmental core service offerings, contribute to the revenues of the Environmental Services operating segment. In addition, sales of packaged blended oil products and other complementary product sales contribute to the revenues of the Environmental Services operating segment. Revenues generated from waste oil, anti-freeze and oil filter collection services, sales of bulk blended oil products and sales of bulk automotive fluids contribute to the Safety-Kleen Sustainability Solutions operating segment. Generally, the service related revenue is recognized over time, as the customer receives and consumes the benefits of the services as they are being performed and the Company has a right to payment for performance completed to date. The duration of such services can be over a number of hours or several days. The Company uses the input method to recognize revenue over time, based on time and materials incurred. Product revenue is recognized upon the transfer of control whereby control transfers when the products are delivered to the customer. Containerized waste services consist of profiling, collecting, transporting and recycling or disposing of a wide variety of waste. Related collection and transportation revenues are recognized over time, as the customer receives and consumes the benefits of the services as they are being performed and the Company has a right to payment for performance completed to date. Parts washer services include customer use of our parts washer equipment, cleaning and maintenance of the parts washer equipment and removal and replacement of used cleaning fluids. Parts washer services are considered a single performance obligation due to the highly integrated and interdependent nature of the arrangement. Revenue from parts washer services is recognized over the service interval as the customer receives the benefit of the services. Safety-Kleen Oil —Safety-Kleen Oil revenues contribute to the revenues of the Safety-Kleen Sustainability Solutions segment. These revenues are generated from sales of high-quality base and blended lubricating oils to third-party distributors, government agencies, fleets, railroads and industrial customers. The business also sells recycled fuel oil to asphalt plants, industrial plants and pulp and paper companies. The used oil is also processed into vacuum gas oil which can be further re-refined into lubricant base oils or sold directly into the marine diesel oil fuel market. Revenue for oil products is recognized at a point in time, upon the transfer of control. Control transfers when the products are delivered to the customer. Disaggregation of Revenue We disaggregate the Company's third party revenues by geographic location and source of revenue as we believe these categories depict how revenue and cash flows are affected by economic factors (in thousands): For the Three Months Ended March 31, 2021 Environmental Services Safety-Kleen Sustainability Solutions Corporate Total Primary Geographical Markets United States $ 575,508 $ 138,990 $ 79 $ 714,577 Canada 77,370 16,201 — 93,571 Total third-party revenues $ 652,878 $ 155,191 $ 79 $ 808,148 Sources of Revenue Technical Services $ 272,040 $ — $ — $ 272,040 Field and Emergency Response Services 105,168 — — 105,168 Industrial Services and Other 119,810 — 79 119,889 Safety-Kleen Environmental Services 155,860 38,978 — 194,838 Safety-Kleen Oil — 116,213 — 116,213 Total third-party revenues $ 652,878 $ 155,191 $ 79 $ 808,148 For the Three Months Ended March 31, 2020 Environmental Services Safety-Kleen Sustainability Solutions Corporate Total Primary Geographical Markets United States $ 607,110 $ 139,437 $ (302) $ 746,245 Canada 97,926 14,000 392 112,318 Total third-party revenues $ 705,036 $ 153,437 $ 90 $ 858,563 Sources of Revenue Technical Services $ 275,273 $ — $ — $ 275,273 Field and Emergency Response Services 105,912 — — 105,912 Industrial Services and Other 146,919 — 90 147,009 Safety-Kleen Environmental Services 176,932 37,549 — 214,481 Safety-Kleen Oil — 115,888 — 115,888 Total third-party revenues $ 705,036 $ 153,437 $ 90 $ 858,563 Contract Balances (in thousands) March 31, 2021 December 31, 2020 Receivables $ 620,184 $ 611,534 Contract assets (unbilled receivables) 55,239 55,681 Contract liabilities (deferred revenue) 83,165 74,066 The timing of revenue recognition, billings and cash collections results in billed accounts receivable, unbilled receivables (contract assets) and customer advances and deposits or deferred revenue (contract liabilities) on the consolidated balance sheet. Generally, billing occurs subsequent to revenue recognition, as a right to payment is not just subject to passage of time, resulting in contract assets. Contract assets are classified as current. The Company sometimes receives advances or deposits from its customers before revenue is recognized, resulting in contract liabilities. These assets and liabilities are reported on the consolidated balance

BUSINESS COMBINATIONS

BUSINESS COMBINATIONS3 Months Ended
Mar. 31, 2021
Business Combinations [Abstract]
BUSINESS COMBINATIONSBUSINESS COMBINATIONS 2021 Acquisition On March 27, 2021, the Company acquired a privately-owned business for $22.9 million cash consideration. The acquired company increases the Safety-Kleen Sustainability Solutions segment's network within the south central United States. In connection with this acquisition, a preliminary goodwill amount of $15.9 million was recognized. 2020 Acquisition On April 17, 2020, the Company acquired a privately-owned business for $8.8 million cash consideration. The acquired company expands the Safety-Kleen Sustainability Solutions segment's oil re-refining operations to the northeast United States. In connection with this acquisition, a preliminary goodwill amount of $1.4 million was recognized.

INVENTORIES AND SUPPLIES

INVENTORIES AND SUPPLIES3 Months Ended
Mar. 31, 2021
Inventory Disclosure [Abstract]
INVENTORIES AND SUPPLIESINVENTORIES AND SUPPLIES Inventories and supplies consisted of the following (in thousands): March 31, 2021 December 31, 2020 Oil and oil related products $ 76,106 $ 76,209 Supplies 120,814 120,007 Solvent and solutions 9,145 8,812 Other 13,434 15,470 Total inventories and supplies $ 219,499 $ 220,498 Supplies consists primarily of critical spare parts to support the Company's incinerator and re-refinery operations, personal protective equipment and other general supplies used in our normal day-to-day operations. Other inventories consisted primarily of parts washer components, cleaning fluids, absorbents and automotive fluids, such as windshield washer fluid and antifreeze.

PROPERTY, PLANT AND EQUIPMENT

PROPERTY, PLANT AND EQUIPMENT3 Months Ended
Mar. 31, 2021
Property, Plant and Equipment [Abstract]
PROPERTY, PLANT AND EQUIPMENTPROPERTY, PLANT AND EQUIPMENT Property, plant and equipment consisted of the following (in thousands): March 31, 2021 December 31, 2020 Land $ 145,662 $ 139,776 Asset retirement costs (non-landfill) 17,747 16,407 Landfill assets 193,009 191,687 Buildings and improvements (1) 514,711 509,804 Camp equipment 158,281 159,021 Vehicles (2) 855,842 844,026 Equipment (3) 1,812,858 1,807,235 Furniture and fixtures 6,992 7,082 Construction in progress 39,943 24,378 3,745,045 3,699,416 Less - accumulated depreciation and amortization 2,217,101 2,174,118 Total property, plant and equipment, net $ 1,527,944 $ 1,525,298 ________________ (1) Balances inclusive of gross right-of-use ("ROU") assets classified as finance leases of $8.9 million in both periods. (2) Balances inclusive of gross ROU assets classified as finance leases of $56.4 million and $47.2 million, respectively. (3) Balances inclusive of gross ROU assets classified as finance leases of $9.4 million and $9.3 million, respectively. Depreciation expense, inclusive of landfill and finance lease amortization, was $64.6 million and $65.4 million for the three months ended March 31, 2021 and March 31, 2020, respectively.

GOODWILL AND OTHER INTANGIBLE A

GOODWILL AND OTHER INTANGIBLE ASSETS3 Months Ended
Mar. 31, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
GOODWILL AND OTHER INTANGIBLE ASSETSGOODWILL AND OTHER INTANGIBLE ASSETS The changes in goodwill by segment for the three months ended March 31, 2021 were as follows (in thousands): Environmental Services Safety-Kleen Sustainability Solutions Totals Balance at January 1, 2021 $ 401,918 $ 125,105 $ 527,023 Increase from current period acquisition — 15,875 15,875 Foreign currency translation 520 187 707 Balance at March 31, 2021 $ 402,438 $ 141,167 $ 543,605 The balances in the table above have been recast to reflect the Company's segment change in the first quarter of 2021. As discussed in Note 17, "Segment Reporting," as a result of operational and managerial changes, the Company changed its operating segments in accordance with ASC 280, Segment Reporting . In addition, the Company concluded that, for purposes of reviewing for potential goodwill impairment, it now has three reporting units. The Environmental Services operating segment has two reporting units consisting of (i) Environmental Sales and Service which includes the legacy Environmental Sales and Service reporting unit and certain operations previously included within Safety-Kleen Environmental Services including the core service offerings of containerized waste, parts washer and vacuum services and (ii) Environmental Facilities, unchanged from prior year. The Safety-Kleen Sustainability Solutions operating segment is a single reporting unit which includes the legacy Safety-Kleen Oil reporting unit and the remaining operations of the legacy Safety-Kleen Environmental Services reporting unit primarily consisting of collection services for waste oil, anti-freeze and used oil filters as well as the sale of bulk blended re-refined oil and other automotive related finished fluid products. The Company allocated goodwill to the newly identified reporting units using a relative fair value approach. In addition, the Company completed an assessment of any potential goodwill impairment for all reporting units immediately prior and subsequent to the reallocation and determined that no impairment existed. As of March 31, 2021 and December 31, 2020, the Company's intangible assets consisted of the following (in thousands): March 31, 2021 December 31, 2020 Cost Accumulated Net Cost Accumulated Net Permits $ 184,675 $ 97,061 $ 87,614 $ 183,766 $ 95,033 $ 88,733 Customer and supplier relationships 372,860 207,929 164,931 382,083 211,895 170,188 Other intangible assets 39,334 35,107 4,227 39,287 34,744 4,543 Total amortizable permits and other intangible assets 596,869 340,097 256,772 605,136 341,672 263,464 Trademarks and trade names 123,281 — 123,281 123,156 — 123,156 Total permits and other intangible assets $ 720,150 $ 340,097 $ 380,053 $ 728,292 $ 341,672 $ 386,620 Amortization expense of permits, customer and supplier relationships and other intangible assets was $7.6 million and $9.2 million in the three months ended March 31, 2021 and March 31, 2020, respectively. The expected amortization of the net carrying amount of finite-lived intangible assets at March 31, 2021 was as follows (in thousands): Years Ending December 31, Expected Amortization 2021 (nine months) $ 22,674 2022 30,013 2023 25,681 2024 24,183 2025 23,205 Thereafter 131,016 $ 256,772

ACCRUED EXPENSES

ACCRUED EXPENSES3 Months Ended
Mar. 31, 2021
Payables and Accruals [Abstract]
ACCRUED EXPENSESACCRUED EXPENSES Accrued expenses consisted of the following (in thousands): March 31, 2021 December 31, 2020 Accrued insurance $ 76,153 $ 77,514 Accrued interest 9,286 19,697 Accrued compensation and benefits 78,928 81,437 Accrued income, real estate, sales and other taxes 30,804 25,843 Interest rate swap liability 28,074 33,630 Accrued other 60,967 57,702 $ 284,212 $ 295,823

CLOSURE AND POST-CLOSURE LIABIL

CLOSURE AND POST-CLOSURE LIABILITIES3 Months Ended
Mar. 31, 2021
Asset Retirement Obligation Disclosure [Abstract]
CLOSURE AND POST-CLOSURE LIABILITIESCLOSURE AND POST-CLOSURE LIABILITIES The changes to closure and post-closure liabilities (also referred to as “asset retirement obligations”) from January 1, 2021 through March 31, 2021 were as follows (in thousands): Landfill Non-Landfill Total Balance at January 1, 2021 $ 48,412 $ 39,514 $ 87,926 Liabilities assumed in acquisitions — 451 451 New asset retirement obligations 646 — 646 Accretion 955 908 1,863 Changes in estimates recorded to consolidated statement of operations — 29 29 Changes in estimates recorded to consolidated balance sheet — 1,045 1,045 Expenditures (751) (178) (929) Currency translation and other 65 9 74 Balance at March 31, 2021 $ 49,327 $ 41,778 $ 91,105 In the three months ended March 31, 2021, there were no significant charges (benefits) resulting from changes in estimates for closure and post-closure liabilities. New asset retirement obligations incurred during the first three months of 2021 were discounted at the credit-adjusted risk-free rate of 4.84%.

REMEDIAL LIABILITIES

REMEDIAL LIABILITIES3 Months Ended
Mar. 31, 2021
Environmental Remediation Obligations [Abstract]
REMEDIAL LIABILITIESREMEDIAL LIABILITIES The changes to remedial liabilities from January 1, 2021 through March 31, 2021 were as follows (in thousands): Remedial Remedial Remedial Total Balance at January 1, 2021 $ 1,865 $ 63,060 $ 49,888 $ 114,813 Accretion 22 654 414 1,090 Changes in estimates recorded to consolidated statement of operations 17 180 49 246 Expenditures (12) (950) (1,120) (2,082) Currency translation and other — (812) 993 181 Balance at March 31, 2021 $ 1,892 $ 62,132 $ 50,224 $ 114,248 In the three months ended March 31, 2021, there were no significant charges (benefits) resulting from changes in estimates for remedial liabilities.

FINANCING ARRANGEMENTS

FINANCING ARRANGEMENTS3 Months Ended
Mar. 31, 2021
Debt Disclosure [Abstract]
FINANCING ARRANGEMENTSFINANCING ARRANGEMENTS The following table is a summary of the Company’s financing arrangements (in thousands): Current Debt: March 31, 2021 December 31, 2020 Secured senior term loans ("Term Loans") $ 7,535 $ 7,535 Long-Term Debt: Secured senior Term Loans due June 30, 2024 $ 717,742 $ 719,626 Unsecured senior notes, at 4.875%, due July 15, 2027 ("2027 Notes") 545,000 545,000 Unsecured senior notes, at 5.125%, due July 15, 2029 ("2029 Notes") 300,000 300,000 Long-term debt, at par $ 1,562,742 $ 1,564,626 Unamortized debt issuance costs and premium, net (14,225) (14,985) Long-term debt, at carrying value $ 1,548,517 $ 1,549,641 Financing Activities As of March 31, 2021 and December 31, 2020, the estimated fair value of the Company’s outstanding long-term debt, including the current portion, was $1.6 billion. The Company’s estimates of fair value of its long-term debt, including the current portion, are based on quoted market prices or other available market data which are considered Level 2 measures according to the fair value hierarchy. Level 2 utilizes quoted market prices in markets that are not active, broker or dealer quotations or alternative pricing sources with reasonable levels of price transparency for similar assets and liabilities. The Company maintains a $400.0 million revolving credit facility under which the Company had no outstanding loan balances as of March 31, 2021 and December 31, 2020. As of March 31, 2021, the Company had $270.2 million available to borrow under the revolving credit facility and outstanding letters of credit were $121.3 million. Cash Flow Hedges The Company’s strategy to hedge against fluctuations in variable interest rates involves entering into interest rate derivative agreements. Although the interest rate on the Term Loans is variable, the Company has effectively fixed the interest rate on $350.0 million aggregate principal amount of the Term Loans outstanding by entering into interest rate swap agreements in 2018 with a notional amount of $350.0 million. Under the terms of the interest rate swap agreements, the Company receives interest based on the one-month LIBOR index and pays interest at a weighted average annual interest rate of 2.92%, resulting in an effective annual interest rate of 4.67%. The interest rate swap agreements terminate in 2024. The Company recognizes derivative instruments as either assets or liabilities on the balance sheet at fair value. No ineffectiveness has been identified on these swaps and, therefore, all unrealized changes in fair value are recorded in accumulated other comprehensive loss. Amounts are reclassified from accumulated other comprehensive loss into interest expense on the statement of operations in the same period or periods during which the hedged transaction affects earnings. As of March 31, 2021 and December 31, 2020, the Company has recorded a derivative liability with a fair value of $28.1 million and $33.6 million, respectively, within accrued expenses in connection with these cash flow hedges. The fair value of the interest rate swaps is calculated using discounted cash flow valuation methodologies based upon the one-month LIBOR yield curves that are observable at commonly quoted intervals for the full term of the interest rate swaps and as such is considered a Level 2 measure according to the fair value hierarchy.

INCOME TAXES

INCOME TAXES3 Months Ended
Mar. 31, 2021
Income Tax Disclosure [Abstract]
INCOME TAXESINCOME 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 months ended March 31, 2021 was 31.5%, compared to 45.6%, respectively, for the comparable period in 2020. As of March 31, 2021 and December 31, 2020, the Company had recorded $5.0 million and $5.5 million, respectively, of liabilities for unrecognized tax benefits and $2.2 million and $2.1 million, respectively, of interest.

EARNINGS PER SHARE

EARNINGS PER SHARE3 Months Ended
Mar. 31, 2021
Earnings Per Share [Abstract]
EARNINGS PER SHAREEARNINGS PER SHARE The following are computations of basic and diluted earnings per share (in thousands, except per share amounts): Three Months Ended March 31, 2021 2020 Numerator for basic and diluted earnings per share: Net income $ 21,736 $ 11,572 Denominator: Basic shares outstanding 54,723 55,757 Dilutive effect of outstanding stock awards 320 298 Dilutive shares outstanding 55,043 56,055 Basic earnings per share: $ 0.40 $ 0.21 Diluted earnings per share: $ 0.39 $ 0.21 For the three months ended March 31, 2021 and March 31, 2020, all then outstanding performance awards and restricted stock awards were included in the calculation of diluted earnings per share except for 34,219 and 121,726, respectively, of performance stock awards for which the performance criteria were not attained at the reporting dates and 6,000 and 9,925, respectively, of restricted stock awards which were excluded as their inclusion would have an antidilutive effect.

ACCUMULATED OTHER COMPREHENSIVE

ACCUMULATED OTHER COMPREHENSIVE LOSS3 Months Ended
Mar. 31, 2021
Equity [Abstract]
ACCUMULATED OTHER COMPREHENSIVE LOSSACCUMULATED OTHER COMPREHENSIVE LOSS The changes in accumulated other comprehensive loss by component and related tax impacts for the three months ended March 31, 2021 were as follows (in thousands): Foreign Currency Translation Unrealized Gains (Losses) on Available-For-Sale Securities Unrealized (Loss) Gain on Interest Rate Hedge Unrealized Loss on Unfunded Pension Liability Total Balance at January 1, 2021 $ (176,234) $ 135 $ (33,629) $ (1,749) $ (211,477) Other comprehensive income (loss) before reclassifications 6,466 (94) 3,108 — 9,480 Amounts reclassified out of accumulated other comprehensive loss — — 2,448 — 2,448 Tax benefit — 20 — — 20 Other comprehensive income (loss) 6,466 (74) 5,556 — 11,948 Balance at March 31, 2021 $ (169,768) $ 61 $ (28,073) $ (1,749) $ (199,529) The amount reclassified out of accumulated other comprehensive loss into the consolidated statement of operations, with presentation location, during the three months ended March 31, 2021 was as follows (in thousands): Other Comprehensive Income (Loss) Components For the Three Months Ended March 31, 2021 Location Unrealized loss on interest rate hedge $ (2,448) Interest expense, net of interest income

STOCK-BASED COMPENSATION

STOCK-BASED COMPENSATION3 Months Ended
Mar. 31, 2021
Share-based Payment Arrangement [Abstract]
STOCK-BASED COMPENSATIONSTOCK-BASED COMPENSATION Total stock-based compensation cost charged to selling, general and administrative expenses for the three months ended March 31, 2021 and March 31, 2020 was $3.5 million and $3.3 million, respectively. The total income tax benefit recognized in the consolidated statements of operations from stock-based compensation expense for the three months ended March 31, 2021 and March 31, 2020 was $0.7 million and $0.8 million, respectively. Restricted Stock Awards The following table summarizes information about restricted stock awards for the three months ended March 31, 2021: Restricted Stock Number of Shares Weighted Average Balance at January 1, 2021 493,879 $ 59.74 Granted 6,000 87.22 Vested (49,578) 56.29 Forfeited (25,205) 60.58 Balance at March 31, 2021 425,096 60.48 As of March 31, 2021, there was $16.6 million of total unrecognized compensation cost arising from restricted stock awards. This cost is expected to be recognized over a weighted average period of 2.7 years. The total fair value of restricted stock vested during the three months ended March 31, 2021 and March 31, 2020 was $4.0 million and $5.3 million, respectively. Performance Stock Awards 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 targets currently based on revenue, Adjusted EBITDA Margin, Adjusted Free Cash Flow and Total Recordable Incident Rate. In addition, performance stock awards include continued service conditions. The following table summarizes information about performance stock awards for the three months ended March 31, 2021: Performance Stock Number of Shares Weighted Average Balance at January 1, 2021 254,449 $ 61.75 Vested (71,815) 62.27 Forfeited (18,395) 61.75 Balance at March 31, 2021 164,239 61.53 As of March 31, 2021, there was $2.9 million of total unrecognized compensation cost arising from unvested performance stock awards deemed probable of vesting. The total fair value of performance awards vested during the three months ended March 31, 2021 and March 31, 2020 was $6.4 million and $1.3 million, respectively.

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES3 Months Ended
Mar. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIESCOMMITMENTS 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 waste. At March 31, 2021 and December 31, 2020, the Company had recorded reserves of $30.2 million and $29.8 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. In management's opinion, it is not reasonably possible that the potential liability beyond what has been recorded, if any, that may result from these actions, either individually or collectively, will have a material effect on our financial position, results of operations or cash flows. 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 March 31, 2021 and December 31, 2020, the $30.2 million and $29.8 million, respectively, of reserves consisted of (i) $23.9 million and $24 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) $6.3 million and $5.8 million, respectively, primarily related to federal, state and provincial enforcement actions, which were included in accrued expenses on the consolidated balance sheets. As of March 31, 2021, the principal legal and administrative proceedings in which the Company was involved, or which had been terminated during 2021, 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 two permits to dump organic liquids into lagoons on the property to a company unrelated to the Mercier Subsidiary. 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 (CAD) in general damages and $10.0 million (CAD) 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 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 future material effect on its financial position, results of operations or cash flows. 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 March 31, 2021 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 69 proceedings (excluding cases which have been settled but not formally dismissed) as of March 31, 2021, wherein persons claim personal injury resulting from the use of Safety-Kleen's parts washer equipment or cleaning products. These proceedings typically involve allegations that the solvent used in Safety-Kleen's parts washer 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 adequately warn the product user of potential risks, including a historic failure to warn that solvent contains trace amounts of toxic or hazardous substances such as benzene. The Company 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. The Company 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 these claims. Such matters are subject to many uncertainties and outcomes are not predictable with assurance. Consequently, the Company is unable to ascertain the ultimate aggregate amount of monetary liability or financial impact with respect to these matters as of March 31, 2021. From January 1, 2021 to March 31, 2021, five 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 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 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 130 sites which are subject to or are proposed to become subject to proceedings under federal or state Superfund laws. Of the 130 Superfund related sites, five (including the BR Facility described below) involve facilities that are now owned or leased by the Company and 125 involve third-party sites to which either the Company or the prior owners of certain of the Company’s facilities shipped wastes. Of the 125 third-party sites, 31 are now settled, 15 are currently requiring expenditures on remediation and 79 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. The Company believes its potential liability could exceed $1.0 million at three of the 130 Superfund related sites. 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 U.S. Environmental Protection Agency ("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 storm water 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. In 2018, the Company completed performing corrective actions at the BR Facility under an order issued by the Louisiana Department of Environmental Quality and has also completed conducting the remedial investigation feasibility study for Devil's Swamp under the order issued by the EPA at which point the feasibility study, with several remedial alternatives, was submitted to the EPA for review. During 2020, the EPA signed a Record of Decision which defined the remediation alternative selected and approved by the EPA and in return, the Company increased the estimated remedial liability for this inactive site by $3.3 million. Changes in the natural landscape and/or new information identified during the remediation could impact this estimate, however are not expected to have a future material effect on the Company's financial position, liquidity or results of operation. Third-Party Sites. Of the 125 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 and 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, McKesson and two other entities, the Company does not have an indemnity agreement with respect to any of the 125 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 March 31, 2021 and December 31, 2020, there were no proceedings for which the Company reasonably believes that the sanctions could equal or exceed $1.0 million. The Company believes that the fines or other penalties in these or any of the other regulatory proceedings will not, individually or in the aggregate, have a material effect on its financial condition, results of operations or cash flows.

SEGMENT REPORTING

SEGMENT REPORTING3 Months Ended
Mar. 31, 2021
Segment Reporting [Abstract]
SEGMENT REPORTINGSEGMENT 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 described in the Changes in Operating Segments section of Note 2, "Significant Accounting Policies" during the first quarter of 2021, certain of the Company's businesses undertook a reorganization which included changes to the underlying business and management structures. The Company's chief operating decision maker also requested changes in the information that he regularly reviews for purposes of allocating resources and assessing performance so that the information would align with the new operating structure of the business. Due to these changes the Company reassessed its operating segment conclusions in the first quarter of 2021 which resulted in a change in the operating segments. The Company consolidated the core services of Safety-Kleen Environmental Services into its Environmental Services segment, eliminated its Safety-Kleen segment and created the Safety-Kleen Sustainability Solutions segment. In addition, certain intercompany transactions previously recorded as Corporate Items have been allocated to the segments. All the historical balances presented below have been recast to reflect the impact of these changes. Third-party revenue is revenue billed to outside customers by a particular segment. Direct revenues 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. Transactions between the segments are accounted for at the Company’s best estimate based on similar transactions with outside customers. The intersegment revenues are shown net. The operations not managed through the Company’s operating segments described above are recorded as “Corporate Items.” The following table reconciles third-party revenues to direct revenues for the three months ended March 31, 2021 and March 31, 2020 (in thousands): For the Three Months Ended March 31, 2021 For the Three Months Ended March 31, 2020 Third-party revenues Intersegment revenues, net Direct revenues Third-party revenues Intersegment revenues, net Direct revenues Environmental Services $ 652,878 $ 1,724 $ 654,602 $ 705,036 $ 156 $ 705,192 Safety-Kleen Sustainability Solutions 155,191 (1,724) 153,467 153,437 (156) 153,281 Corporate Items 79 — 79 90 — 90 Total $ 808,148 $ — $ 808,148 $ 858,563 $ — $ 858,563 The primary financial measure by which the Company evaluates the performance of its segments is "Adjusted EBITDA," which consists of net income plus accretion of environmental liabilities, stock-based compensation, depreciation and amortization, net interest expense, loss on early extinguishment of debt, provision for income taxes and excludes other gains, losses or non-cash charges not deemed representative of fundamental segment results and other expense, net. Beginning in the first quarter of 2021, we revised our calculation of reported Adjusted EBITDA to add stock-based compensation, a non-cash item, to other charges which are added back to net income determined in accordance with generally accepted accounting principles ("GAAP") for purposes of calculating Adjusted EBITDA. The amount added back each period matches the line item for stock-based compensation as recorded on the consolidated statements of cash flows. All relevant prior period Adjusted EBITDA amounts were recast to provide comparative information. The following table presents Adjusted EBITDA information used by management by reported segment (in thousands): For the Three Months Ended March 31, 2021 2020 Adjusted EBITDA: Environmental Services $ 140,254 $ 145,858 Safety-Kleen Sustainability Solutions 31,632 24,204 Corporate Items (42,435) (44,181) Total 129,451 125,881 Reconciliation to Consolidated Statements of Operations: Accretion of environmental liabilities 2,953 2,561 Stock-based compensation 3,480 3,291 Depreciation and amortization 72,163 74,533 Income from operations 50,855 45,496 Other expense, net 1,228 2,365 Loss on sale of businesses — 3,074 Interest expense, net of interest income 17,918 18,787 Income before provision for income taxes $ 31,709 $ 21,270 The following table presents certain assets by reportable segment and in the aggregate (in thousands): March 31, 2021 December 31, 2020 Property, plant and equipment, net: Environmental Services $ 1,056,053 $ 1,068,910 Safety-Kleen Sustainability Solutions 367,689 366,160 Corporate Items 104,202 90,228 Total property, plant and equipment, net $ 1,527,944 $ 1,525,298 Goodwill and Permits and other intangibles, net: Environmental Services Goodwill $ 402,438 $ 401,918 Permits and other intangibles, net 224,614 228,237 Total Environmental Services 627,052 630,155 Safety-Kleen Sustainability Solutions Goodwill $ 141,167 $ 125,105 Permits and other intangibles, net 155,439 158,383 Total Safety-Kleen Sustainability Solutions 296,606 283,488 Total $ 923,658 $ 913,643 The following table presents the total assets by geographical area (in thousands): March 31, 2021 December 31, 2020 United States $ 3,472,053 $ 3,447,811 Canada and other foreign 680,486 683,709 Total $ 4,152,539 $ 4,131,520

SIGNIFICANT ACCOUNTING POLICI_2

SIGNIFICANT ACCOUNTING POLICIES (Policies)3 Months Ended
Mar. 31, 2021
Accounting Policies [Abstract]
Changes in Operating SegmentsDuring the first quarter of 2021, the Company reorganized its Safety-Kleen business. The collection services for waste oil, used oil filters, antifreeze and related items and bulk blended oil sales operations were combined with the Safety-Kleen Oil business to form the Safety-Kleen Sustainability Solutions business. Under this structure, Safety-Kleen Sustainability Solutions will encompass both sides of the spread the Company manages in its re-refinery business, and the Company expects this change to drive additional growth in its sustainable lubricant products and related services. Concurrently with this change, the Company consolidated the Safety-Kleen branches' core offerings, including containerized waste, parts washer and vacuum services, into the legacy Clean Harbors Environmental Services sales and service operations. The Company expects this change to foster enhanced cross-selling opportunities within the environmental businesses and increase market presence with small quantity generators of hazardous waste. In restructuring the operations of the Company in this manner, the information that the chief operating decision maker regularly reviews for purposes of allocating resources and assessing performance changed to conform to this new operating structure of the business and the Company reevaluated the identification of its operating segments. In accordance with ASC 280, Segment Reporting, Environmental Services and Safety-Kleen Sustainability Solutions are the Company's operating segments and reportable segments starting in the first quarter of 2021,
Revenue recognitionThe Company generates revenues through its Environmental Services and Safety-Kleen Sustainability Solutions operating segments. The Company's Environmental Services operating segment generally has four sources of revenue and the Safety-Kleen Sustainability Solutions operating segment has two sources of revenue. Technical Services —Technical Services contribute to the revenues of the Environmental Services operating segment. These services are generated from fees charged for waste material management and disposal services including onsite environmental management services, collection and transportation, packaging, recycling, treatment and disposal of waste. Revenue is primarily generated by short-term projects, most of which are governed by master service agreements that are long-term in nature. These master service agreements are typically entered into with the Company's larger customers and outline the pricing and legal frameworks for such arrangements. Services are provided based on purchase orders or agreements with the customer and include prices based upon units of volume of waste and transportation and other fees. Collection and transportation revenues are recognized over time, as the customer receives and consumes the benefits of the services as they are being performed and the Company has a right to payment for performance completed to date. The Company uses the input method to recognize revenue over time, based on time and materials incurred. Revenues for treatment and disposal of waste are recognized upon completion of treatment, final disposition in a landfill or incineration, or when the waste is shipped to a third party for processing and disposal. The Company periodically enters into bundled arrangements for the collection and transportation and disposal of waste. For such arrangements, transportation and disposal are considered distinct performance obligations and the Company allocates revenue to each based on the relative standalone selling price (i.e., the estimated price that a customer would pay for the services on a standalone basis). Revenues from waste that is not yet completely processed and disposed and the related costs are deferred. The deferred revenues and costs are recognized when the related services are completed. The period between collection and transportation and the final processing and disposal ranges depending on the location of the customer, but generally is measured in days. Field and Emergency Response Services —Field and Emergency Response Services contribute to the revenues of the Environmental Services operating segment. Field Services revenues are generated from cleanup services at customer sites, including municipalities and utilities, or other locations on a scheduled or emergency response basis. Services include confined space entry for tank cleaning, site decontamination, large remediation projects, demolition, spill cleanup on land and water, railcar cleaning, product recovery and transfer and vacuum services. Additional services include filtration and water treatment services. Response services for environmental, contamination or pandemic related emergencies include any scale from man-made disasters such as oil spills to natural disasters such as hurricanes. More recently demand has increased for projects involving contagion disinfection, decontamination and disposal services in response to the COVID-19 pandemic. Field and emergency response services are provided based on purchase orders or agreements with customers and include prices generally based upon daily, hourly or job rates for equipment, materials and personnel. The Company recognizes revenue for these services over time, as the customer receives and consumes the benefits of the service as they are being performed and the Company has a right to payment for performance completed to date. The Company uses the input method to recognize revenue over time, based on time and materials incurred. The duration of such services can be over a number of hours, several days or even months for larger scale projects. Industrial Services and Other —Industrial Services contribute to the revenues of the Environmental Services operating segment. These revenues are primarily generated from industrial and specialty services provided to refineries, mines, upgraders, chemical plants, pulp and paper mills, manufacturing facilities, power generation facilities and other industrial customers throughout North America. Services include in-plant cleaning and maintenance services, plant outage and turnaround services, specialty cleaning services including chemical cleaning and high and ultra-high pressure water cleaning, daylighting, production services and upstream energy services. Services are provided based on purchase orders or agreements with the customer and include prices based upon daily, hourly or job rates for equipment, materials and personnel. The Company recognizes revenue for these services over time, as the customer receives and consumes the benefits of the services as they are being performed and the Company has a right to payment for performance completed to date. The Company uses the input method to recognize revenue over time, based on time and materials incurred. Safety-Kleen Environmental Services —Safety-Kleen Environmental Services revenues contribute both to the Environmental Services operating segment and the Safety-Kleen Sustainability Solutions operating segment depending upon the nature of such revenues and operating responsibilities relative to driving these revenues. Revenues from providing containerized waste handling and disposal services, parts washer services and vacuum services, referred to collectively as the Safety-Kleen Environmental core service offerings, contribute to the revenues of the Environmental Services operating segment. In addition, sales of packaged blended oil products and other complementary product sales contribute to the revenues of the Environmental Services operating segment. Revenues generated from waste oil, anti-freeze and oil filter collection services, sales of bulk blended oil products and sales of bulk automotive fluids contribute to the Safety-Kleen Sustainability Solutions operating segment. Generally, the service related revenue is recognized over time, as the customer receives and consumes the benefits of the services as they are being performed and the Company has a right to payment for performance completed to date. The duration of such services can be over a number of hours or several days. The Company uses the input method to recognize revenue over time, based on time and materials incurred. Product revenue is recognized upon the transfer of control whereby control transfers when the products are delivered to the customer. Containerized waste services consist of profiling, collecting, transporting and recycling or disposing of a wide variety of waste. Related collection and transportation revenues are recognized over time, as the customer receives and consumes the benefits of the services as they are being performed and the Company has a right to payment for performance completed to date. Parts washer services include customer use of our parts washer equipment, cleaning and maintenance of the parts washer equipment and removal and replacement of used cleaning fluids. Parts washer services are considered a single performance obligation due to the highly integrated and interdependent nature of the arrangement. Revenue from parts washer services is recognized over the service interval as the customer receives the benefit of the services. Safety-Kleen Oil —Safety-Kleen Oil revenues contribute to the revenues of the Safety-Kleen Sustainability Solutions segment. These revenues are generated from sales of high-quality base and blended lubricating oils to third-party distributors, government agencies, fleets, railroads and industrial customers. The business also sells recycled fuel oil to asphalt plants, industrial plants and pulp and paper companies. The used oil is also processed into vacuum gas oil which can be further re-refined into lubricant base oils or sold directly into the marine diesel oil fuel market. Revenue for oil products is recognized at a point in time, upon the transfer of control. Control transfers when the products are delivered to the customer.

REVENUES (Tables)

REVENUES (Tables)3 Months Ended
Mar. 31, 2021
Revenue from Contract with Customer [Abstract]
Schedule of Disaggregation of RevenueWe disaggregate the Company's third party revenues by geographic location and source of revenue as we believe these categories depict how revenue and cash flows are affected by economic factors (in thousands): For the Three Months Ended March 31, 2021 Environmental Services Safety-Kleen Sustainability Solutions Corporate Total Primary Geographical Markets United States $ 575,508 $ 138,990 $ 79 $ 714,577 Canada 77,370 16,201 — 93,571 Total third-party revenues $ 652,878 $ 155,191 $ 79 $ 808,148 Sources of Revenue Technical Services $ 272,040 $ — $ — $ 272,040 Field and Emergency Response Services 105,168 — — 105,168 Industrial Services and Other 119,810 — 79 119,889 Safety-Kleen Environmental Services 155,860 38,978 — 194,838 Safety-Kleen Oil — 116,213 — 116,213 Total third-party revenues $ 652,878 $ 155,191 $ 79 $ 808,148 For the Three Months Ended March 31, 2020 Environmental Services Safety-Kleen Sustainability Solutions Corporate Total Primary Geographical Markets United States $ 607,110 $ 139,437 $ (302) $ 746,245 Canada 97,926 14,000 392 112,318 Total third-party revenues $ 705,036 $ 153,437 $ 90 $ 858,563 Sources of Revenue Technical Services $ 275,273 $ — $ — $ 275,273 Field and Emergency Response Services 105,912 — — 105,912 Industrial Services and Other 146,919 — 90 147,009 Safety-Kleen Environmental Services 176,932 37,549 — 214,481 Safety-Kleen Oil — 115,888 — 115,888 Total third-party revenues $ 705,036 $ 153,437 $ 90 $ 858,563
Schedule of Contract Balances(in thousands) March 31, 2021 December 31, 2020 Receivables $ 620,184 $ 611,534 Contract assets (unbilled receivables) 55,239 55,681 Contract liabilities (deferred revenue) 83,165 74,066

INVENTORIES AND SUPPLIES (Table

INVENTORIES AND SUPPLIES (Tables)3 Months Ended
Mar. 31, 2021
Inventory Disclosure [Abstract]
Schedule of Inventories and SuppliesInventories and supplies consisted of the following (in thousands): March 31, 2021 December 31, 2020 Oil and oil related products $ 76,106 $ 76,209 Supplies 120,814 120,007 Solvent and solutions 9,145 8,812 Other 13,434 15,470 Total inventories and supplies $ 219,499 $ 220,498

PROPERTY, PLANT AND EQUIPMENT (

PROPERTY, PLANT AND EQUIPMENT (Tables)3 Months Ended
Mar. 31, 2021
Property, Plant and Equipment [Abstract]
Schedule of Property, Plant and EquipmentProperty, plant and equipment consisted of the following (in thousands): March 31, 2021 December 31, 2020 Land $ 145,662 $ 139,776 Asset retirement costs (non-landfill) 17,747 16,407 Landfill assets 193,009 191,687 Buildings and improvements (1) 514,711 509,804 Camp equipment 158,281 159,021 Vehicles (2) 855,842 844,026 Equipment (3) 1,812,858 1,807,235 Furniture and fixtures 6,992 7,082 Construction in progress 39,943 24,378 3,745,045 3,699,416 Less - accumulated depreciation and amortization 2,217,101 2,174,118 Total property, plant and equipment, net $ 1,527,944 $ 1,525,298 ________________ (1) Balances inclusive of gross right-of-use ("ROU") assets classified as finance leases of $8.9 million in both periods. (2) Balances inclusive of gross ROU assets classified as finance leases of $56.4 million and $47.2 million, respectively. (3) Balances inclusive of gross ROU assets classified as finance leases of $9.4 million and $9.3 million, respectively.

GOODWILL AND OTHER INTANGIBLE_2

GOODWILL AND OTHER INTANGIBLE ASSETS (Tables)3 Months Ended
Mar. 31, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Changes to GoodwillThe changes in goodwill by segment for the three months ended March 31, 2021 were as follows (in thousands): Environmental Services Safety-Kleen Sustainability Solutions Totals Balance at January 1, 2021 $ 401,918 $ 125,105 $ 527,023 Increase from current period acquisition — 15,875 15,875 Foreign currency translation 520 187 707 Balance at March 31, 2021 $ 402,438 $ 141,167 $ 543,605
Schedule of Finite-Lived Intangible AssetsAs of March 31, 2021 and December 31, 2020, the Company's intangible assets consisted of the following (in thousands): March 31, 2021 December 31, 2020 Cost Accumulated Net Cost Accumulated Net Permits $ 184,675 $ 97,061 $ 87,614 $ 183,766 $ 95,033 $ 88,733 Customer and supplier relationships 372,860 207,929 164,931 382,083 211,895 170,188 Other intangible assets 39,334 35,107 4,227 39,287 34,744 4,543 Total amortizable permits and other intangible assets 596,869 340,097 256,772 605,136 341,672 263,464 Trademarks and trade names 123,281 — 123,281 123,156 — 123,156 Total permits and other intangible assets $ 720,150 $ 340,097 $ 380,053 $ 728,292 $ 341,672 $ 386,620
Summary of Indefinite-Lived Intangible AssetsAs of March 31, 2021 and December 31, 2020, the Company's intangible assets consisted of the following (in thousands): March 31, 2021 December 31, 2020 Cost Accumulated Net Cost Accumulated Net Permits $ 184,675 $ 97,061 $ 87,614 $ 183,766 $ 95,033 $ 88,733 Customer and supplier relationships 372,860 207,929 164,931 382,083 211,895 170,188 Other intangible assets 39,334 35,107 4,227 39,287 34,744 4,543 Total amortizable permits and other intangible assets 596,869 340,097 256,772 605,136 341,672 263,464 Trademarks and trade names 123,281 — 123,281 123,156 — 123,156 Total permits and other intangible assets $ 720,150 $ 340,097 $ 380,053 $ 728,292 $ 341,672 $ 386,620
Schedule of Expected Amortization for the Net Carrying Amount of Finite Lived Intangible AssetsThe expected amortization of the net carrying amount of finite-lived intangible assets at March 31, 2021 was as follows (in thousands): Years Ending December 31, Expected Amortization 2021 (nine months) $ 22,674 2022 30,013 2023 25,681 2024 24,183 2025 23,205 Thereafter 131,016 $ 256,772

ACCRUED EXPENSES (Tables)

ACCRUED EXPENSES (Tables)3 Months Ended
Mar. 31, 2021
Payables and Accruals [Abstract]
Schedule of Accrued ExpensesAccrued expenses consisted of the following (in thousands): March 31, 2021 December 31, 2020 Accrued insurance $ 76,153 $ 77,514 Accrued interest 9,286 19,697 Accrued compensation and benefits 78,928 81,437 Accrued income, real estate, sales and other taxes 30,804 25,843 Interest rate swap liability 28,074 33,630 Accrued other 60,967 57,702 $ 284,212 $ 295,823

CLOSURE AND POST-CLOSURE LIAB_2

CLOSURE AND POST-CLOSURE LIABILITIES (Tables)3 Months Ended
Mar. 31, 2021
Asset Retirement Obligation Disclosure [Abstract]
Schedule of Closure and Post-Closure LiabilitiesThe changes to closure and post-closure liabilities (also referred to as “asset retirement obligations”) from January 1, 2021 through March 31, 2021 were as follows (in thousands): Landfill Non-Landfill Total Balance at January 1, 2021 $ 48,412 $ 39,514 $ 87,926 Liabilities assumed in acquisitions — 451 451 New asset retirement obligations 646 — 646 Accretion 955 908 1,863 Changes in estimates recorded to consolidated statement of operations — 29 29 Changes in estimates recorded to consolidated balance sheet — 1,045 1,045 Expenditures (751) (178) (929) Currency translation and other 65 9 74 Balance at March 31, 2021 $ 49,327 $ 41,778 $ 91,105

REMEDIAL LIABILITIES (Tables)

REMEDIAL LIABILITIES (Tables)3 Months Ended
Mar. 31, 2021
Environmental Remediation Obligations [Abstract]
Schedule of Changes to Remedial LiabilitiesThe changes to remedial liabilities from January 1, 2021 through March 31, 2021 were as follows (in thousands): Remedial Remedial Remedial Total Balance at January 1, 2021 $ 1,865 $ 63,060 $ 49,888 $ 114,813 Accretion 22 654 414 1,090 Changes in estimates recorded to consolidated statement of operations 17 180 49 246 Expenditures (12) (950) (1,120) (2,082) Currency translation and other — (812) 993 181 Balance at March 31, 2021 $ 1,892 $ 62,132 $ 50,224 $ 114,248

FINANCING ARRANGEMENTS (Tables)

FINANCING ARRANGEMENTS (Tables)3 Months Ended
Mar. 31, 2021
Debt Disclosure [Abstract]
Schedule of the Entity's Financial ArrangementsThe following table is a summary of the Company’s financing arrangements (in thousands): Current Debt: March 31, 2021 December 31, 2020 Secured senior term loans ("Term Loans") $ 7,535 $ 7,535 Long-Term Debt: Secured senior Term Loans due June 30, 2024 $ 717,742 $ 719,626 Unsecured senior notes, at 4.875%, due July 15, 2027 ("2027 Notes") 545,000 545,000 Unsecured senior notes, at 5.125%, due July 15, 2029 ("2029 Notes") 300,000 300,000 Long-term debt, at par $ 1,562,742 $ 1,564,626 Unamortized debt issuance costs and premium, net (14,225) (14,985) Long-term debt, at carrying value $ 1,548,517 $ 1,549,641

EARNINGS PER SHARE (Tables)

EARNINGS PER SHARE (Tables)3 Months Ended
Mar. 31, 2021
Earnings Per Share [Abstract]
Schedule of Reconciliation of Basic and Diluted Earnings per Share ComputationsThe following are computations of basic and diluted earnings per share (in thousands, except per share amounts): Three Months Ended March 31, 2021 2020 Numerator for basic and diluted earnings per share: Net income $ 21,736 $ 11,572 Denominator: Basic shares outstanding 54,723 55,757 Dilutive effect of outstanding stock awards 320 298 Dilutive shares outstanding 55,043 56,055 Basic earnings per share: $ 0.40 $ 0.21 Diluted earnings per share: $ 0.39 $ 0.21

ACCUMULATED OTHER COMPREHENSI_2

ACCUMULATED OTHER COMPREHENSIVE LOSS (Tables)3 Months Ended
Mar. 31, 2021
Equity [Abstract]
Schedule of Accumulated Other Comprehensive LossThe changes in accumulated other comprehensive loss by component and related tax impacts for the three months ended March 31, 2021 were as follows (in thousands): Foreign Currency Translation Unrealized Gains (Losses) on Available-For-Sale Securities Unrealized (Loss) Gain on Interest Rate Hedge Unrealized Loss on Unfunded Pension Liability Total Balance at January 1, 2021 $ (176,234) $ 135 $ (33,629) $ (1,749) $ (211,477) Other comprehensive income (loss) before reclassifications 6,466 (94) 3,108 — 9,480 Amounts reclassified out of accumulated other comprehensive loss — — 2,448 — 2,448 Tax benefit — 20 — — 20 Other comprehensive income (loss) 6,466 (74) 5,556 — 11,948 Balance at March 31, 2021 $ (169,768) $ 61 $ (28,073) $ (1,749) $ (199,529)
Schedule of Reclassification Out of Accumulated Other Comprehensive IncomeThe amount reclassified out of accumulated other comprehensive loss into the consolidated statement of operations, with presentation location, during the three months ended March 31, 2021 was as follows (in thousands): Other Comprehensive Income (Loss) Components For the Three Months Ended March 31, 2021 Location Unrealized loss on interest rate hedge $ (2,448) Interest expense, net of interest income

STOCK-BASED COMPENSATION (Table

STOCK-BASED COMPENSATION (Tables)3 Months Ended
Mar. 31, 2021
Share-based Payment Arrangement [Abstract]
Schedule of Restricted Stock AwardsThe following table summarizes information about restricted stock awards for the three months ended March 31, 2021: Restricted Stock Number of Shares Weighted Average Balance at January 1, 2021 493,879 $ 59.74 Granted 6,000 87.22 Vested (49,578) 56.29 Forfeited (25,205) 60.58 Balance at March 31, 2021 425,096 60.48
Schedule of Performance Stock AwardsThe following table summarizes information about performance stock awards for the three months ended March 31, 2021: Performance Stock Number of Shares Weighted Average Balance at January 1, 2021 254,449 $ 61.75 Vested (71,815) 62.27 Forfeited (18,395) 61.75 Balance at March 31, 2021 164,239 61.53

SEGMENT REPORTING (Tables)

SEGMENT REPORTING (Tables)3 Months Ended
Mar. 31, 2021
Segment Reporting [Abstract]
Reconciliation of Third Party Revenues to Direct RevenuesThe following table reconciles third-party revenues to direct revenues for the three months ended March 31, 2021 and March 31, 2020 (in thousands): For the Three Months Ended March 31, 2021 For the Three Months Ended March 31, 2020 Third-party revenues Intersegment revenues, net Direct revenues Third-party revenues Intersegment revenues, net Direct revenues Environmental Services $ 652,878 $ 1,724 $ 654,602 $ 705,036 $ 156 $ 705,192 Safety-Kleen Sustainability Solutions 155,191 (1,724) 153,467 153,437 (156) 153,281 Corporate Items 79 — 79 90 — 90 Total $ 808,148 $ — $ 808,148 $ 858,563 $ — $ 858,563
Reconciliation to Consolidated Statements of Income to Adjusted EBITDAThe following table presents Adjusted EBITDA information used by management by reported segment (in thousands): For the Three Months Ended March 31, 2021 2020 Adjusted EBITDA: Environmental Services $ 140,254 $ 145,858 Safety-Kleen Sustainability Solutions 31,632 24,204 Corporate Items (42,435) (44,181) Total 129,451 125,881 Reconciliation to Consolidated Statements of Operations: Accretion of environmental liabilities 2,953 2,561 Stock-based compensation 3,480 3,291 Depreciation and amortization 72,163 74,533 Income from operations 50,855 45,496 Other expense, net 1,228 2,365 Loss on sale of businesses — 3,074 Interest expense, net of interest income 17,918 18,787 Income before provision for income taxes $ 31,709 $ 21,270
Schedule of Assets by SegmentThe following table presents certain assets by reportable segment and in the aggregate (in thousands): March 31, 2021 December 31, 2020 Property, plant and equipment, net: Environmental Services $ 1,056,053 $ 1,068,910 Safety-Kleen Sustainability Solutions 367,689 366,160 Corporate Items 104,202 90,228 Total property, plant and equipment, net $ 1,527,944 $ 1,525,298 Goodwill and Permits and other intangibles, net: Environmental Services Goodwill $ 402,438 $ 401,918 Permits and other intangibles, net 224,614 228,237 Total Environmental Services 627,052 630,155 Safety-Kleen Sustainability Solutions Goodwill $ 141,167 $ 125,105 Permits and other intangibles, net 155,439 158,383 Total Safety-Kleen Sustainability Solutions 296,606 283,488 Total $ 923,658 $ 913,643
Long-lived Assets by Geographic AreasThe following table presents the total assets by geographical area (in thousands): March 31, 2021 December 31, 2020 United States $ 3,472,053 $ 3,447,811 Canada and other foreign 680,486 683,709 Total $ 4,152,539 $ 4,131,520

REVENUES (Disaggregation of Rev

REVENUES (Disaggregation of Revenue) (Details) - USD ($) $ in Thousands3 Months Ended
Mar. 31, 2021Mar. 31, 2020
Disaggregation of Revenue [Line Items]
Total revenues $ 808,148 $ 858,563
Technical Services
Disaggregation of Revenue [Line Items]
Total revenues272,040 275,273
Field and Emergency Response Services
Disaggregation of Revenue [Line Items]
Total revenues105,168 105,912
Industrial Services and Other
Disaggregation of Revenue [Line Items]
Total revenues119,889 147,009
Safety-Kleen Environmental Services
Disaggregation of Revenue [Line Items]
Total revenues194,838 214,481
Safety-Kleen Oil
Disaggregation of Revenue [Line Items]
Total revenues116,213 115,888
United States
Disaggregation of Revenue [Line Items]
Total revenues714,577 746,245
Canada
Disaggregation of Revenue [Line Items]
Total revenues93,571 112,318
Environmental Services
Disaggregation of Revenue [Line Items]
Total revenues654,602 705,192
Safety-Kleen Sustainability Solutions
Disaggregation of Revenue [Line Items]
Total revenues153,467 153,281
Operating segments | Environmental Services
Disaggregation of Revenue [Line Items]
Total revenues652,878 705,036
Operating segments | Environmental Services | Technical Services
Disaggregation of Revenue [Line Items]
Total revenues272,040 275,273
Operating segments | Environmental Services | Field and Emergency Response Services
Disaggregation of Revenue [Line Items]
Total revenues105,168 105,912
Operating segments | Environmental Services | Industrial Services and Other
Disaggregation of Revenue [Line Items]
Total revenues119,810 146,919
Operating segments | Environmental Services | Safety-Kleen Environmental Services
Disaggregation of Revenue [Line Items]
Total revenues155,860 176,932
Operating segments | Environmental Services | Safety-Kleen Oil
Disaggregation of Revenue [Line Items]
Total revenues0 0
Operating segments | Environmental Services | United States
Disaggregation of Revenue [Line Items]
Total revenues575,508 607,110
Operating segments | Environmental Services | Canada
Disaggregation of Revenue [Line Items]
Total revenues77,370 97,926
Operating segments | Safety-Kleen Sustainability Solutions
Disaggregation of Revenue [Line Items]
Total revenues155,191 153,437
Operating segments | Safety-Kleen Sustainability Solutions | Technical Services
Disaggregation of Revenue [Line Items]
Total revenues0 0
Operating segments | Safety-Kleen Sustainability Solutions | Field and Emergency Response Services
Disaggregation of Revenue [Line Items]
Total revenues0 0
Operating segments | Safety-Kleen Sustainability Solutions | Industrial Services and Other
Disaggregation of Revenue [Line Items]
Total revenues0 0
Operating segments | Safety-Kleen Sustainability Solutions | Safety-Kleen Environmental Services
Disaggregation of Revenue [Line Items]
Total revenues38,978 37,549
Operating segments | Safety-Kleen Sustainability Solutions | Safety-Kleen Oil
Disaggregation of Revenue [Line Items]
Total revenues116,213 115,888
Operating segments | Safety-Kleen Sustainability Solutions | United States
Disaggregation of Revenue [Line Items]
Total revenues138,990 139,437
Operating segments | Safety-Kleen Sustainability Solutions | Canada
Disaggregation of Revenue [Line Items]
Total revenues16,201 14,000
Corporate, non-Segment
Disaggregation of Revenue [Line Items]
Total revenues79 90
Corporate, non-Segment | Technical Services
Disaggregation of Revenue [Line Items]
Total revenues0 0
Corporate, non-Segment | Field and Emergency Response Services
Disaggregation of Revenue [Line Items]
Total revenues0 0
Corporate, non-Segment | Industrial Services and Other
Disaggregation of Revenue [Line Items]
Total revenues79 90
Corporate, non-Segment | Safety-Kleen Environmental Services
Disaggregation of Revenue [Line Items]
Total revenues0 0
Corporate, non-Segment | Safety-Kleen Oil
Disaggregation of Revenue [Line Items]
Total revenues0 0
Corporate, non-Segment | United States
Disaggregation of Revenue [Line Items]
Total revenues79 (302)
Corporate, non-Segment | Canada
Disaggregation of Revenue [Line Items]
Total revenues $ 0 $ 392

REVENUES (Contract Balances) (D

REVENUES (Contract Balances) (Details) - USD ($) $ in ThousandsMar. 31, 2021Dec. 31, 2020
Revenue from Contract with Customer [Abstract]
Receivables $ 620,184 $ 611,534
Contract assets (unbilled receivables)55,239 55,681
Contract liabilities (deferred revenue) $ 83,165 $ 74,066

REVENUES (Narrative) (Details)

REVENUES (Narrative) (Details)3 Months Ended
Mar. 31, 2021source
Disaggregation of Revenue [Line Items]
Deferred contract cost, recognition period3 months
Environmental Services
Disaggregation of Revenue [Line Items]
Number of revenue sources4
Safety-Kleen Sustainability Solutions
Disaggregation of Revenue [Line Items]
Number of revenue sources2

BUSINESS COMBINATIONS (Details)

BUSINESS COMBINATIONS (Details) - USD ($) $ in ThousandsMar. 27, 2021Apr. 17, 2020Mar. 31, 2021
Business Acquisition [Line Items]
Goodwill recognized $ 15,875
2021 Acquisitions
Business Acquisition [Line Items]
Purchase price $ 22,900
Goodwill recognized $ 15,900
2020 Acquisitions
Business Acquisition [Line Items]
Purchase price $ 8,800
Goodwill recognized $ 1,400

INVENTORIES AND SUPPLIES (Detai

INVENTORIES AND SUPPLIES (Details) - USD ($) $ in ThousandsMar. 31, 2021Dec. 31, 2020
Inventory [Line Items]
Inventories and supplies $ 219,499 $ 220,498
Oil and oil related products
Inventory [Line Items]
Inventories and supplies76,106 76,209
Supplies
Inventory [Line Items]
Inventories and supplies120,814 120,007
Solvent and solutions
Inventory [Line Items]
Inventories and supplies9,145 8,812
Other
Inventory [Line Items]
Inventories and supplies $ 13,434 $ 15,470

PROPERTY, PLANT AND EQUIPMENT_2

PROPERTY, PLANT AND EQUIPMENT (Schedule of Property, Plant and Equipment) (Details) - USD ($) $ in ThousandsMar. 31, 2021Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross $ 3,745,045 $ 3,699,416
Less - accumulated depreciation and amortization2,217,101 2,174,118
Total property, plant and equipment, net1,527,944 1,525,298
Land
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross145,662 139,776
Asset retirement costs (non-landfill)
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross17,747 16,407
Landfill assets
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross193,009 191,687
Buildings and improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross514,711 509,804
Right-of-Use assets, finance leases8,900 8,900
Camp equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross158,281 159,021
Vehicles
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross855,842 844,026
Right-of-Use assets, finance leases56,400 47,200
Equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross1,812,858 1,807,235
Right-of-Use assets, finance leases9,400 9,300
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross6,992 7,082
Construction in progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross $ 39,943 $ 24,378

PROPERTY, PLANT AND EQUIPMENT_3

PROPERTY, PLANT AND EQUIPMENT (Narrative) (Details) - USD ($) $ in Millions3 Months Ended
Mar. 31, 2021Mar. 31, 2020
Property, Plant and Equipment [Abstract]
Depreciation expense, inclusive of landfill and finance lease amortization $ 64.6 $ 65.4

GOODWILL AND OTHER INTANGIBLE_3

GOODWILL AND OTHER INTANGIBLE ASSETS (Changes to Goodwill) (Details) $ in Thousands3 Months Ended
Mar. 31, 2021USD ($)
Goodwill [Roll Forward]
Balance at January 1, 2021 $ 527,023
Increase from current period acquisition15,875
Foreign currency translation707
Balance at March 31, 2021543,605
Environmental Services
Goodwill [Roll Forward]
Balance at January 1, 2021401,918
Increase from current period acquisition0
Foreign currency translation520
Balance at March 31, 2021402,438
Safety-Kleen Sustainability Solutions
Goodwill [Roll Forward]
Balance at January 1, 2021125,105
Increase from current period acquisition15,875
Foreign currency translation187
Balance at March 31, 2021 $ 141,167

GOODWILL AND OTHER INTANGIBLE_4

GOODWILL AND OTHER INTANGIBLE ASSETS (Finite-lived and Indefinite Lived Intangible Assets) (Details) - USD ($) $ in ThousandsMar. 31, 2021Dec. 31, 2020
Schedule of Finite-lived and Indefinite-lived Intangible Assets [Line Items]
Finite-lived intangible assets, cost $ 596,869 $ 605,136
Accumulated Amortization340,097 341,672
Finite-lived intangible assets, net256,772 263,464
Total permits and other intangible assets, Cost720,150 728,292
Total permits and other intangible assets, Net380,053 386,620
Trademarks and trade names
Schedule of Finite-lived and Indefinite-lived Intangible Assets [Line Items]
Trademarks and trade names123,281 123,156
Permits
Schedule of Finite-lived and Indefinite-lived Intangible Assets [Line Items]
Finite-lived intangible assets, cost184,675 183,766
Accumulated Amortization97,061 95,033
Finite-lived intangible assets, net87,614 88,733
Customer and supplier relationships
Schedule of Finite-lived and Indefinite-lived Intangible Assets [Line Items]
Finite-lived intangible assets, cost372,860 382,083
Accumulated Amortization207,929 211,895
Finite-lived intangible assets, net164,931 170,188
Other intangible assets
Schedule of Finite-lived and Indefinite-lived Intangible Assets [Line Items]
Finite-lived intangible assets, cost39,334 39,287
Accumulated Amortization35,107 34,744
Finite-lived intangible assets, net $ 4,227 $ 4,543

GOODWILL AND OTHER INTANGIBLE_5

GOODWILL AND OTHER INTANGIBLE ASSETS (Narrative) (Details) $ in Millions3 Months Ended
Mar. 31, 2021USD ($)reportingUnitMar. 31, 2020USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
Number of reporting units | reportingUnit3
Amortization of permits and other intangible assets | $ $ 7.6 $ 9.2

GOODWILL AND OTHER INTANGIBLE_6

GOODWILL AND OTHER INTANGIBLE ASSETS (Expected Future Amortization) (Details) - USD ($) $ in ThousandsMar. 31, 2021Dec. 31, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
2021 (nine months) $ 22,674
202230,013
202325,681
202424,183
202523,205
Thereafter131,016
Finite-lived intangible assets, net $ 256,772 $ 263,464

ACCRUED EXPENSES (Details)

ACCRUED EXPENSES (Details) - USD ($) $ in ThousandsMar. 31, 2021Dec. 31, 2020
Payables and Accruals [Abstract]
Accrued insurance $ 76,153 $ 77,514
Accrued interest9,286 19,697
Accrued compensation and benefits78,928 81,437
Accrued income, real estate, sales and other taxes30,804 25,843
Interest rate swap liability28,074 33,630
Accrued other60,967 57,702
Total accrued expenses $ 284,212 $ 295,823

CLOSURE AND POST-CLOSURE LIAB_3

CLOSURE AND POST-CLOSURE LIABILITIES (Changes in Post-Closure Liabilities) (Details) $ in Thousands3 Months Ended
Mar. 31, 2021USD ($)
Changes to post-closure liabilities
Balance at January 1, 2021 $ 87,926
Liabilities assumed in acquisitions451
New asset retirement obligations646
Accretion1,863
Changes in estimates recorded to consolidated statement of operations29
Changes in estimates recorded to consolidated balance sheet1,045
Expenditures(929)
Currency translation and other74
Balance at March 31, 202191,105
Landfill Retirement Liability
Changes to post-closure liabilities
Balance at January 1, 202148,412
Liabilities assumed in acquisitions0
New asset retirement obligations646
Accretion955
Changes in estimates recorded to consolidated statement of operations0
Changes in estimates recorded to consolidated balance sheet0
Expenditures(751)
Currency translation and other65
Balance at March 31, 202149,327
Non-Landfill Retirement Liability
Changes to post-closure liabilities
Balance at January 1, 202139,514
Liabilities assumed in acquisitions451
New asset retirement obligations0
Accretion908
Changes in estimates recorded to consolidated statement of operations29
Changes in estimates recorded to consolidated balance sheet1,045
Expenditures(178)
Currency translation and other9
Balance at March 31, 2021 $ 41,778

CLOSURE AND POST-CLOSURE LIAB_4

CLOSURE AND POST-CLOSURE LIABILITIES (Narrative) (Details)3 Months Ended
Mar. 31, 2021
Asset Retirement Obligation Disclosure [Abstract]
Credit-adjusted risk-free rate4.84%

REMEDIAL LIABILITIES (Changes i

REMEDIAL LIABILITIES (Changes in Remedial Liabilities) (Details) $ in Thousands3 Months Ended
Mar. 31, 2021USD ($)
Accrual for Environmental Loss Contingencies [Roll Forward]
Balance at January 1, 2021 $ 114,813
Accretion1,090
Changes in estimates recorded to consolidated statement of operations246
Expenditures(2,082)
Currency translation and other181
Balance at March 31, 2021114,248
Remedial Liabilities for Landfill Sites
Accrual for Environmental Loss Contingencies [Roll Forward]
Balance at January 1, 20211,865
Accretion22
Changes in estimates recorded to consolidated statement of operations17
Expenditures(12)
Currency translation and other0
Balance at March 31, 20211,892
Remedial Liabilities for Inactive Sites
Accrual for Environmental Loss Contingencies [Roll Forward]
Balance at January 1, 202163,060
Accretion654
Changes in estimates recorded to consolidated statement of operations180
Expenditures(950)
Currency translation and other(812)
Balance at March 31, 202162,132
Remedial Liabilities (Including Superfund) for Non-Landfill Operations
Accrual for Environmental Loss Contingencies [Roll Forward]
Balance at January 1, 202149,888
Accretion414
Changes in estimates recorded to consolidated statement of operations49
Expenditures(1,120)
Currency translation and other993
Balance at March 31, 2021 $ 50,224

FINANCING ARRANGEMENTS - Summar

FINANCING ARRANGEMENTS - Summary of Financing Arrangements (Details) - USD ($) $ in ThousandsMar. 31, 2021Dec. 31, 2020
Debt Instrument [Line Items]
Current portion of long-term debt $ 7,535 $ 7,535
Long-term debt, at par1,562,742 1,564,626
Unamortized debt issuance costs and premium, net(14,225)(14,985)
Long-term debt, at carrying value1,548,517 1,549,641
Secured debt | Secured senior Term Loans due June 30, 2024
Debt Instrument [Line Items]
Current portion of long-term debt7,535 7,535
Long-term debt, at par717,742 719,626
Unsecured debt | Unsecured senior notes, at 4.875%, due July 15, 2027 ("2027 Notes")
Debt Instrument [Line Items]
Long-term debt, at par $ 545,000 $ 545,000
Interest rate (as a percentage)4.875%4.875%
Unsecured debt | Unsecured senior notes, at 5.125%, due July 15, 2029 ("2029 Notes")
Debt Instrument [Line Items]
Long-term debt, at par $ 300,000 $ 300,000
Interest rate (as a percentage)5.125%5.125%

FINANCING ARRANGEMENTS - Narrat

FINANCING ARRANGEMENTS - Narrative (Details) - USD ($)3 Months Ended
Mar. 31, 2021Dec. 31, 2020
Debt Instrument [Line Items]
Debt fair value $ 1,600,000,000 $ 1,600,000,000
Available to borrow and outstanding letters of credit270,200,000
Outstanding letters of credit $ 121,300,000
Effective interest rate percentage4.67%
Interest rate swap, liability $ 28,100,000 33,600,000
Interest Rate Swap
Debt Instrument [Line Items]
Notional amount of interest rate swap agreements $ 350,000,000
Interest rate percentage2.92%
Term Loans with Interest Rate Swap Agreements
Debt Instrument [Line Items]
Debt outstanding $ 350,000,000
Revolving Credit Facility | Line of Credit
Debt Instrument [Line Items]
Revolving credit facility maximum borrowing capacity $ 400,000,000 $ 400,000,000

INCOME TAXES (Details)

INCOME TAXES (Details) - USD ($) $ in Millions3 Months Ended
Mar. 31, 2021Mar. 31, 2020Dec. 31, 2020
Income Tax Disclosure [Abstract]
Effective income tax rate31.50%45.60%
Unrecognized tax benefits $ 5 $ 5.5
Interest on unrecognized tax benefits $ 2.2 $ 2.1

EARNINGS PER SHARE (Reconciliat

EARNINGS PER SHARE (Reconciliation of Basic and Diluted Earnings Per Share Computations) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands3 Months Ended
Mar. 31, 2021Mar. 31, 2020
Numerator for basic and diluted earnings per share:
Net income $ 21,736 $ 11,572
Denominator:
Basic shares outstanding (in shares)54,723 55,757
Dilutive effect of outstanding stock awards (in shares)320 298
Dilutive shares outstanding (in shares)55,043 56,055
Basic earnings per share (in dollars per share) $ 0.40 $ 0.21
Diluted earnings per share (in dollars per share) $ 0.39 $ 0.21

EARNINGS PER SHARE (Anti-Diluti

EARNINGS PER SHARE (Anti-Dilutive Securities) (Details) - shares3 Months Ended
Mar. 31, 2021Mar. 31, 2020
Performance stock awards
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive shares excluded from computation of earning per share (in shares)34,219 121,726
Restricted stock awards
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive shares excluded from computation of earning per share (in shares)6,000 9,925

ACCUMULATED OTHER COMPREHENSI_3

ACCUMULATED OTHER COMPREHENSIVE LOSS - Changes in Accumulated Other Comprehensive Loss by Component (Details) - USD ($) $ in Thousands3 Months Ended
Mar. 31, 2021Mar. 31, 2020
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance beginning of period $ 1,341,551 $ 1,269,813
Other comprehensive income (loss) before reclassifications9,480
Amounts reclassified out of accumulated other comprehensive loss2,448
Tax benefit20
Other comprehensive income (loss), net of tax11,948 (59,306)
Balance ending of period1,348,450 1,205,805
Foreign Currency Translation
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance beginning of period(176,234)
Other comprehensive income (loss) before reclassifications6,466
Amounts reclassified out of accumulated other comprehensive loss0
Tax benefit0
Other comprehensive income (loss), net of tax6,466
Balance ending of period(169,768)
Unrealized Gains (Losses) on Available-For-Sale Securities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance beginning of period135
Other comprehensive income (loss) before reclassifications(94)
Amounts reclassified out of accumulated other comprehensive loss0
Tax benefit20
Other comprehensive income (loss), net of tax(74)
Balance ending of period61
Unrealized (Loss) Gain on Interest Rate Hedge
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance beginning of period(33,629)
Other comprehensive income (loss) before reclassifications3,108
Amounts reclassified out of accumulated other comprehensive loss2,448
Tax benefit0
Other comprehensive income (loss), net of tax5,556
Balance ending of period(28,073)
Unrealized Loss on Unfunded Pension Liability
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance beginning of period(1,749)
Other comprehensive income (loss) before reclassifications0
Amounts reclassified out of accumulated other comprehensive loss0
Tax benefit0
Other comprehensive income (loss), net of tax0
Balance ending of period(1,749)
Total
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance beginning of period(211,477)(210,051)
Other comprehensive income (loss), net of tax11,948 (59,306)
Balance ending of period $ (199,529) $ (269,357)

ACCUMULATED OTHER COMPREHENSI_4

ACCUMULATED OTHER COMPREHENSIVE LOSS - Reclassified Out of Accumulated Other Comprehensive Loss (Details) $ in Thousands3 Months Ended
Mar. 31, 2021USD ($)
Unrealized (Loss) Gain on Interest Rate Hedge
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense, net of interest income $ (2,448)

STOCK-BASED COMPENSATION - Addi

STOCK-BASED COMPENSATION - Additional Information (Details) - USD ($) $ in Millions3 Months Ended
Mar. 31, 2021Mar. 31, 2020
Share-based Payment Arrangement [Abstract]
Stock-based compensation $ 3.5 $ 3.3
Income tax benefit $ 0.7 $ 0.8

STOCK-BASED COMPENSATION - Rest

STOCK-BASED COMPENSATION - Restricted Stock Awards (Details) - Restricted stock awards - USD ($) $ / shares in Units, $ in Millions3 Months Ended
Mar. 31, 2021Mar. 31, 2020
Number of Shares
Beginning balance (in shares)493,879
Granted (in shares)6,000
Vested (in shares)(49,578)
Forfeited (in shares)(25,205)
Ending balance (in shares)425,096
Weighted Average Grant-Date Fair Value
Beginning of period (in dollars per share) $ 59.74
Granted (in dollars per share)87.22
Vested (in dollars per share)56.29
Forfeited (in dollars per share)60.58
End of period (in dollars per share) $ 60.48
Unrecognized compensation cost $ 16.6
Period for recognition (in years)2 years 8 months 12 days
Fair value restricted stock $ 4 $ 5.3

STOCK-BASED COMPENSATION - Perf

STOCK-BASED COMPENSATION - Performance Stock Awards (Details) - Performance stock awards - USD ($) $ / shares in Units, $ in Millions3 Months Ended
Mar. 31, 2021Mar. 31, 2020
Number of Shares
Beginning balance (in shares)254,449
Vested (in shares)(71,815)
Forfeited (in shares)(18,395)
Ending balance (in shares)164,239
Weighted Average Grant-Date Fair Value
Beginning of period (in dollars per share) $ 61.75
Vested (in dollars per share)62.27
Forfeited (in dollars per share)61.75
End of period (in dollars per share) $ 61.53
Unrecognized compensation cost $ 2.9
Fair value restricted stock $ 6.4 $ 1.3

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Details) $ in Millions3 Months Ended12 Months Ended
Mar. 31, 2021USD ($)siteproceedingclaimDec. 31, 2012CAD ($)Dec. 31, 1999municipalityDec. 31, 1968permitDec. 31, 2020USD ($)proceeding
Loss Contingencies [Line Items]
Recorded reserves for actual or probable liabilities | $ $ 30,200,000 $ 29,800,000
Number of proceedings as defendant | proceeding69
Number of product liability claims settled or dismissed | claim5
Legal and Administrative Proceedings
Loss Contingencies [Line Items]
Recorded reserves for actual or probable liabilities | $ $ 23,900,000 24,000,000
Ville Mercier
Loss Contingencies [Line Items]
Number of permits issued by government, for dumping organic liquid | permit2
Number of neighboring municipalities filing separate legal proceedings against the Mercier Subsidiary and the Government of Quebec | municipality3
General damages sought | $ $ 2.9
Punitive damages sought | $ $ 10
Superfund Proceedings
Loss Contingencies [Line Items]
Number of sites owned by third party excluded from cleanup or related liabilities130
Number of sites owned by the entity subject to proceedings under federal or state superfund laws5
Number of sites owned by third parties125
Number of sites for which environmental remediation expense is settled31
Third party sites requiring expenditure on remediation15
Number of sites not currently requiring expenditures on remediation79
Minimum potential liability | $ $ 1,000,000
Number of sites, potential liability exceeds substantial quota3
Notices received from owners of third parties sites seeking indemnifications from the company17
BR Facility | Remedial Liabilities for Inactive Sites
Loss Contingencies [Line Items]
Increase of remedial liabilities | $ $ 3,300,000
ChemWaste
Loss Contingencies [Line Items]
Indemnification agreement with third party sites11
Kleen Performance Products
Loss Contingencies [Line Items]
Notices received from owners of third parties sites seeking indemnifications from the company6
Federal and State Enforcement Actions
Loss Contingencies [Line Items]
Recorded reserves for actual or probable liabilities | $ $ 6,300,000 $ 5,800,000
Number of proceedings as defendant | proceeding0 0
Minimum potential liability | $ $ 1,000,000 $ 1,000,000

SEGMENT REPORTING (Segment Info

SEGMENT REPORTING (Segment Information, Revenues, EBITA, and Reconciliation to the Consolidated Statement of Operations) (Details) - USD ($) $ in Thousands3 Months Ended
Mar. 31, 2021Mar. 31, 2020Dec. 31, 2020
Segment Reporting Information [Line Items]
Total revenues $ 808,148 $ 858,563
Adjusted EBITDA129,451 125,881
Reconciliation of Net Income to Adjusted EBITDA [Abstract]
Accretion of environmental liabilities2,953 2,561
Stock-based compensation3,480 3,291
Depreciation and amortization72,163 74,533
Income from operations50,855 45,496
Other expense, net1,228 2,365
Loss on sale of businesses0 3,074
Interest expense, net of interest income17,918 18,787
Income before provision for income taxes31,709 21,270
Property, plant and equipment, net1,527,944 $ 1,525,298
Goodwill543,605 527,023
Permits and other intangibles, net380,053 386,620
Permits and other intangibles, net923,658 913,643
Environmental Services
Segment Reporting Information [Line Items]
Total revenues654,602 705,192
Reconciliation of Net Income to Adjusted EBITDA [Abstract]
Goodwill402,438 401,918
Safety-Kleen Sustainability Solutions
Segment Reporting Information [Line Items]
Total revenues153,467 153,281
Reconciliation of Net Income to Adjusted EBITDA [Abstract]
Goodwill141,167 125,105
Operating segments | Environmental Services
Segment Reporting Information [Line Items]
Total revenues652,878 705,036
Adjusted EBITDA140,254 145,858
Reconciliation of Net Income to Adjusted EBITDA [Abstract]
Property, plant and equipment, net1,056,053 1,068,910
Goodwill402,438 401,918
Permits and other intangibles, net224,614 228,237
Permits and other intangibles, net627,052 630,155
Operating segments | Safety-Kleen Sustainability Solutions
Segment Reporting Information [Line Items]
Total revenues155,191 153,437
Adjusted EBITDA31,632 24,204
Reconciliation of Net Income to Adjusted EBITDA [Abstract]
Property, plant and equipment, net367,689 366,160
Goodwill141,167 125,105
Permits and other intangibles, net155,439 158,383
Permits and other intangibles, net296,606 283,488
Intersegment revenues, net | Environmental Services
Segment Reporting Information [Line Items]
Total revenues1,724 156
Intersegment revenues, net | Safety-Kleen Sustainability Solutions
Segment Reporting Information [Line Items]
Total revenues(1,724)(156)
Corporate, non-Segment
Segment Reporting Information [Line Items]
Total revenues79 90
Adjusted EBITDA(42,435)(44,181)
Reconciliation of Net Income to Adjusted EBITDA [Abstract]
Property, plant and equipment, net104,202 $ 90,228
Operating and Corporate non-segment
Segment Reporting Information [Line Items]
Total revenues $ 79 $ 90

SEGMENT REPORTING (Geographical

SEGMENT REPORTING (Geographical Information) (Details) - USD ($) $ in ThousandsMar. 31, 2021Dec. 31, 2020
Revenues from External Customers and Long-Lived Assets [Line Items]
Total assets $ 4,152,539 $ 4,131,520
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Total assets3,472,053 3,447,811
Canada and other foreign
Revenues from External Customers and Long-Lived Assets [Line Items]
Total assets $ 680,486 $ 683,709