Clean Harbors — Jul 30, 2025 release

EXHIBIT 99.1 Press Release                                             Clean Harbors Announces Second-Quarter 2025 Financial Results • Reports Revenue of $1.55 Billion with Growth in Environmental Services • Delivers Strong Incineration Performance Based on Robust Demand • Generates Q2 Net Income of $126.9 Million, or EPS of $2.36 • Achieves Record Q2 Adjusted EBITDA of $336.2 Million; Increases Adjusted EBITDA Margin 60 bps to 21.7% • Confirms Full-Year 2025 Adjusted EBITDA and Adjusted Free Cash Flow Guidance NORWELL, Mass. – July 30, 2025 – Clean Harbors, Inc. (“Clean Harbors” or the “Company”) (NYSE: CLH), the leading provider of environmental and industrial services throughout North America, today announced financial results for the second quarter ended June 30, 2025. “Our second-quarter results reflect the consistent profitable growth of our Environmental Services (ES) segment, where we experienced strong demand for our disposal assets, and a stabilization of our Safety-Kleen Sustainability Solutions (SKSS) segment, where our collection strategies yielded favorable results,” said Mike Battles, Co-Chief Executive Officer. “We improved our consolidated Adjusted EBITDA margin by 60 basis points from a year ago through lowering our overall cost structure with a sharp focus on our SG&A spend. In addition, we posted the best quarterly safety results in our history by generating a Total Recordable Incident Rate (TRIR) of just 0.40. We stand at 0.45 for the first half of the year – well on track to achieve our annual target as our programs and emphasis on working safely are helping to keep our employees protected.” Second-Quarter 2025 Results Revenues were $1.55 billion, flat with the same period of 2024. Income from operations was $210.3 million, compared with $215.5 million in the second quarter of 2024. Net income was $126.9 million, or $2.36 per diluted share, compared with $133.3 million, or $2.46 per diluted share, for the same period in 2024. Adjusted EBITDA (see description and reconciliation below) increased to $336.2 million, compared with $327.8 million in the same period of 2024. Q2 2025 Segment Review “Despite substantial growth in the year ago quarter, our ES segment still achieved 3% growth in revenue and 5% growth in Adjusted EBITDA. This revenue growth, combined with pricing and SG&A cost controls, Clean Harbors • 42 Longwater Drive • PO Box 9149 • Norwell, Massachusetts 02061-9149 • 800.282.0058 • www.cleanharbors.com enabled our ES segment to achieve its 13th consecutive quarter of year-over-year improvement in segment Adjusted EBITDA margin,” said Eric Gerstenberg, Co-Chief Executive Officer. “Top-line growth in the segment was led by Safety-Kleen Environmental Services, which rose 9% through pricing and growth in its core offerings. Technical Services revenue grew 4% on strength in disposal volumes. Incineration utilization, excluding the new Kimball incinerator, was outstanding at 89% as our facilities maximized throughput. Average incineration price rose 7% on a mix-adjusted basis. Field Services and Industrial Services performed well in the quarter, improving margins year-over-year.” “Results in our SKSS segment were ahead of our expectations, supported by our waste oil collection strategies and success in aggressively managing our re-refining spread,” said Battles. “We gathered 64 million gallons of waste oil in the quarter, which enabled us to hit our production goals. We believe that our shift to higher charge-for-oil (CFO) pricing, which has continued since our strategic program rollout last November, positions us well for the back half of the year. We currently expect to achieve our annual targets for this business in 2025, while reducing the volatility we’ve seen in recent years.” Business Outlook and Financial Guidance “We enter the back half of 2025 with considerable momentum across our core markets, backed by a promising North American economic outlook as reshoring continues,” Gerstenberg said. “While tariff uncertainty has impacted some customers in the short-term, we expect the tangible benefits of the recent tax bill and incentives to invest in American manufacturing to drive customer activity over the longer-term. We continue to see healthy overall demand from customers within our ES segment, resulting in a substantial project pipeline. Multiple customers are expected to proceed with remediation projects in the coming quarters, which will further support our disposal and recycling network. We are excited about the continued progress at our new Kimball incinerator, which achieved its Q2 volume target. We look forward to further ramping up the facility with a broader mix of waste streams in the second half of this year. For SKSS, our focus will remain on actively managing our collection rates and cost structure, while advancing value-added initiatives like our Castrol partnership and Group III production.” Battles concluded, “We anticipate a strong second half of the year for the Company based on numerous tailwinds that should drive both top- and bottom-line improvement from a year ago. With an encouraging market outlook, we are also continuing to execute on our pricing strategies, cost mitigation and operational efficiencies to drive further margin improvement.” In the third quarter of 2025, Clean Harbors expects Adjusted EBITDA to grow 9-12% from the comparable quarter of the prior year. For full-year 2025, Clean Harbors is reiterating the midpoints of its prior guidance and expects: Clean Harbors • 42 Longwater Drive • PO Box 9149 • Norwell, Massachusetts 02061-9149 • 800.282.0058 • www.cleanharbors.com • Adjusted EBITDA in the range of $1.16 billion to $1.20 billion, or a midpoint of $1.18 billion, which represents 6% growth year over year. This Adjusted EBITDA range is based on anticipated GAAP net income in the range of $383 million to $419 million. • Adjusted free cash flow in the range of $430 million to $490 million, or a midpoint of $460 million, which represents a nearly 30% increase from prior year. This range is based on anticipated net cash from operating activities in the range of $775 million to $865 million. Non-GAAP Results Clean Harbors reports Adjusted EBITDA, which is a non-GAAP financial measure and should not be considered an alternative to net income or other measurements under generally accepted accounting principles (GAAP) but viewed only as a supplement to those measurements. Adjusted EBITDA is not calculated identically by all companies, and therefore the Company’s measurement of Adjusted EBITDA may not be comparable to similarly titled measures reported by other companies. Clean Harbors believes that Adjusted EBITDA provides additional useful information to investors because the Company’s management routinely evaluates the performance of its businesses based upon levels of Adjusted EBITDA. The Company defines Adjusted EBITDA as described in the following reconciliation showing the differences between reported GAAP net income and Adjusted EBITDA (in thousands, except percentages): Three Months Ended Six Months Ended June 30, 2025 June 30, 2024 June 30, 2025 June 30, 2024 Net income $ 126,905  $ 133,280  $ 185,585  $ 203,112  Accretion of environmental liabilities 3,591  3,304  7,211  6,521  Stock-based compensation 6,063  8,515  13,698  14,853  Depreciation and amortization 116,285  100,504  228,265  195,569  Other expense, net 603  167  1,535  1,308  Interest expense, net of interest income 37,106  36,449  73,183  64,988  Provision for income taxes 45,684  45,597  61,614  71,560  Adjusted EBITDA $ 336,237  $ 327,816  $ 571,091  $ 557,911  Adjusted EBITDA Margin 21.7  % 21.1  % 19.2  % 19.0  % Adjusted Free Cash Flow Reconciliation Clean Harbors reports adjusted free cash flow, a non-GAAP measure, which it considers to be a measurement of liquidity that provides useful information to investors about its ability to generate cash. The Company defines adjusted free cash flow as net cash from operating activities less additions to property, plant and equipment plus proceeds from sale and disposal of fixed assets. When necessary, the Company adjusts for the cash impact of items derived from non-operating activities. Adjusted free cash flow should not be considered an alternative to net cash from operating activities or other measurements under GAAP. Adjusted free cash flow is not calculated identically by all companies, and therefore the Company’s measurement of adjusted free cash flow may not be comparable to similarly titled measures reported by other companies. Clean Harbors • 42 Longwater Drive • PO Box 9149 • Norwell, Massachusetts 02061-9149 • 800.282.0058 • www.cleanharbors.com An itemized reconciliation between reported GAAP net cash from operating activities and adjusted free cash flow is as follows (in thousands): Three Months Ended Six Months Ended June 30, 2025 June 30, 2024 June 30, 2025 June 30, 2024 Net cash from operating activities $ 208,040  $ 216,045  $ 209,645  $ 234,594  Additions to property, plant and equipment (90,029) (135,110) (208,724) (273,023) Cash investment in Phoenix Hub 12,436  —  12,436  —  Proceeds from sale and disposal of fixed assets 2,720  3,287  4,063  4,295  Adjusted free cash flow $ 133,167  $ 84,222  $ 17,420  $ (34,134) Adjusted EBITDA Guidance Reconciliation An itemized reconciliation between projected GAAP net income and projected Adjusted EBITDA is as follows (in millions): For the Year Ending December 31, 2025 Projected GAAP net income $383 to $419 Adjustments: Accretion of environmental liabilities 15 to 14 Stock-based compensation 28 to 31 Depreciation and amortization 450 to 440 Interest expense, net 147 to 142 Provision for income taxes 137 to 154 Projected Adjusted EBITDA $1,160 to $1,200 Adjusted Free Cash Flow Guidance Reconciliation An itemized reconciliation between projected GAAP net cash from operating activities and projected adjusted free cash flow is as follows (in millions). The Company excludes significant one-time growth investments, which the Company expects to realize future long-term benefits from, as they are not indicative of free cash flow generation for the current period. For the Year Ending December 31, 2025 Projected net cash from operating activities $775 to $865 Additions to property, plant and equipment (370) to (400) Cash investment in Phoenix Hub 15 to 15 Proceeds from sale and disposal of fixed assets 10 to 10 Projected adjusted free cash flow $430 to $490 Conference Call Information Clean Harbors will conduct a conference call for investors today at 9:00 a.m. (ET) to discuss the information contained in this press release. During the call, management will discuss Clean Harbors’ financial results, business outlook and growth strategy. Investors who wish to listen to the webcast and view the accompanying Clean Harbors • 42 Longwater Drive • PO Box 9149 • Norwell, Massachusetts 02061-9149 • 800.282.0058 • www.cleanharbors.com slides should visit the Investor Relations section of the Company’s website at www.cleanharbors.com . The live call also can be accessed by dialing 877.709.8155 or 201.689.8881 prior to the start time. If you are unable to listen to the live conference call, the webcast will be archived on the Company’s website. About Clean Harbors Clean Harbors (NYSE: CLH) is North America’s leading provider of environmental and industrial services. The Company serves a diverse customer base, including a majority of Fortune 500 companies. Its customer base spans a number of industries, including chemical, manufacturing and refining, as well as numerous government agencies. These customers rely on Clean Harbors to deliver a broad range of services such as end-to-end hazardous waste management, emergency spill response, industrial cleaning and maintenance, and recycling services. Through its Safety-Kleen subsidiary, Clean Harbors also is a leading provider of parts washers and environmental services to commercial, industrial and automotive customers, as well as North America’s largest re-refiner and recycler of used oil. Founded in 1980 and based in Massachusetts, Clean Harbors operates in the United States, Canada, Mexico, Puerto Rico and India. For more information, visit www.cleanharbors.com . Safe Harbor Statement Any statements contained herein that are not historical facts are forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. These forward-looking statements are generally identifiable by use of the words “believes,” “expects,” “intends,” “anticipates,” “plans to,” “seeks,” “will,” “should,” “estimates,” “projects,” “may,” “likely,” “potential,” “outlook” or similar expressions. Such statements may include, but are not limited to, statements about the Company’s future financial and operating results, plans, strategy, objectives and goals, cost management initiatives, pricing and productivity initiatives, contingent liabilities, liquidity, business, economic and market conditions, trends, customer demand, impacts of tariffs and new legislation, acquisitions, growth opportunities, expectations, challenges and other statements that are not historical facts. Such statements are based upon the beliefs and expectations of Clean Harbors’ management as of the date of this press release only and are subject to certain risks and uncertainties that could cause actual results to differ materially, including, without limitation: operational and safety risks; risks relating to the failure of new or existing technologies; cybersecurity risks; the occurrence of natural disasters or other catastrophic events, as well as their residual macroeconomic effects; risks associated with retaining and hiring key personnel; environmental liability and product liability risks relating to hazardous waste management and other components of the Company’s business; negative economic, industry or other developments, including market volatility or economic downturns; risks associated with management’s assumptions relating to expansion of the Company’s landfills; reductions in the demand for emergency response services at industrial facilities or on roadways, railways or waterways, and other remedial projects and regulatory developments; reductions in the demand for oil products and automotive services and volatility in oil prices in the markets the Company serves; changes in statutory and regulatory requirements and risks relating to extensive environmental laws and regulations; risks associated with existing and potential litigation; risks associated with the Company’s identification and execution of strategic acquisitions and divestitures and their related liabilities; risks relating to the availability and sufficiency of the Company’s insurance coverage, self-insurance, surety bonds, letters of credit and other forms of financial assurance; the impact of new tax legislation or changes in tax regulations and Clean Harbors • 42 Longwater Drive • PO Box 9149 • Norwell, Massachusetts 02061-9149 • 800.282.0058 • www.cleanharbors.com interpretations; the imposition of trade sanctions or tariffs; fluctuations in interest rates and foreign currency exchange rates; risks relating to the Company’s indebtedness and covenants in its debt agreements; risks associated with certain anti-takeover provisions under the Massachusetts Business Corporation Act and the Company’s By-Laws, and those items identified as “Risk Factors” in Clean Harbors’ most recently filed reports on Form 10-K and Form 10-Q. Forward-looking statements are neither historical facts nor assurances of future performance. Therefore, readers are cautioned not to place undue reliance on these forward-looking statements. Clean Harbors undertakes no obligation to revise or publicly release the results of any revision to these forward-looking statements other than through its filings with the Securities and Exchange Commission, which may be viewed in the “Investors” section of Clean Harbors’ website at www.cleanharbors.com. Contacts: Eric J. Dugas Jim Buckley EVP and Chief Financial Officer SVP Investor Relations Clean Harbors, Inc. Clean Harbors, Inc. 781.792.5100 781.792.5100 InvestorRelations@cleanharbors.com Buckley.James@cleanharbors.com      Clean Harbors • 42 Longwater Drive • PO Box 9149 • Norwell, Massachusetts 02061-9149 • 800.282.0058 • www.cleanharbors.com CLEAN HARBORS, INC. AND SUBSIDIARIES UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (in thousands, except per share amounts)   Three Months Ended Six Months Ended June 30, June 30, 2025 2024 2025 2024 Revenues $ 1,549,854  $ 1,552,719  $ 2,981,804  $ 2,929,414  Cost of revenues (exclusive of items shown separately below) 1,033,497  1,035,542  2,055,381  2,006,612  Selling, general and administrative expenses 186,183  197,876  369,030  379,744  Accretion of environmental liabilities 3,591  3,304  7,211  6,521  Depreciation and amortization 116,285  100,504  228,265  195,569  Income from operations 210,298  215,493  321,917  340,968  Other expense, net (603) (167) (1,535) (1,308) Interest expense, net (37,106) (36,449) (73,183) (64,988) Income before provision for income taxes 172,589  178,877  247,199  274,672  Provision for income taxes 45,684  45,597  61,614  71,560  Net income $ 126,905  $ 133,280  $ 185,585  $ 203,112  Earnings per share:     Basic $ 2.37  $ 2.47  $ 3.46  $ 3.77  Diluted $ 2.36  $ 2.46  $ 3.44  $ 3.75  Shares used to compute earnings per share - Basic 53,593 53,932 53,675 53,931 Shares used to compute earnings per share - Diluted 53,799 54,248 53,895 54,231 Clean Harbors • 42 Longwater Drive • PO Box 9149 • Norwell, Massachusetts 02061-9149 • 800.282.0058 • www.cleanharbors.com CLEAN HARBORS, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATED BALANCE SHEETS (in thousands) June 30, 2025 December 31, 2024 Current assets: (unaudited)   Cash and cash equivalents $ 600,186  $ 687,192  Short-term marketable securities 98,888  102,634  Accounts receivable, net 1,117,714  1,015,357  Unbilled accounts receivable 177,910  162,215  Inventories and supplies 383,351  384,657  Prepaid expenses and other current assets 97,332  81,741  Total current assets 2,475,381  2,433,796  Property, plant and equipment, net 2,507,101  2,447,941  Other assets: Operating lease right-of-use assets 247,033  250,853  Goodwill 1,479,805  1,477,199  Permits and other intangibles, net 677,180  701,987  Other long-term assets 53,429  65,502  Total other assets 2,457,447  2,495,541  Total assets $ 7,439,929  $ 7,377,278  Current liabilities: Current portion of long-term debt $ 15,102  $ 15,102  Accounts payable 432,771  487,286  Deferred revenue 87,792  88,545  Accrued expenses and other current liabilities 376,585  419,445  Current portion of closure, post-closure and remedial liabilities 26,524  20,625  Current portion of operating lease liabilities 72,976  71,663  Total current liabilities 1,011,750  1,102,666  Other liabilities:   Closure and post-closure liabilities, less current portion 122,795  119,484  Remedial liabilities, less current portion 86,880  101,424  Long-term debt, less current portion 2,766,530  2,771,117  Operating lease liabilities, less current portion 178,343  182,883  Deferred tax liabilities 359,661  363,623  Other long-term liabilities 199,903  162,552  Total other liabilities 3,714,112  3,701,083         Total stockholders’ equity, net 2,714,067  2,573,529         Total liabilities and stockholders’ equity $ 7,439,929  $ 7,377,278  Clean Harbors • 42 Longwater Drive • PO Box 9149 • Norwell, Massachusetts 02061-9149 • 800.282.0058 • www.cleanharbors.com CLEAN HARBORS, INC. AND SUBSIDIARIES UNAUDITED CONSOLIDATED STATEMENTS OF CASH FLOWS (in thousands) Six Months Ended June 30, 2025 June 30, 2024 Cash flows from operating activities: Net income $ 185,585  $ 203,112  Adjustments to reconcile net income to net cash from operating activities: Depreciation and amortization 228,265  195,569  Allowance for doubtful accounts 3,249  4,349  Amortization of deferred financing costs and debt discount 3,352  2,937  Accretion of environmental liabilities 7,211  6,521  Changes in environmental liability estimates (8,954) 3,963  Deferred income taxes —  (88) Other expense, net 1,535  1,308  Stock-based compensation 13,698  14,853  Environmental expenditures (7,051) (9,934) Changes in assets and liabilities, net of acquisitions: Accounts receivable and unbilled accounts receivable (116,399) (116,307) Inventories and supplies 2,952  (28,673) Other current and long-term assets (13,395) (28,870) Accounts payable (36,035) (12,418) Other current and long-term liabilities (54,368) (1,728) Net cash from operating activities 209,645  234,594  Cash flows used in investing activities: Additions to property, plant and equipment (208,724) (273,023) Proceeds from sale and disposal of fixed assets 4,063  4,295  Acquisitions, net of cash acquired —  (477,201) Proceeds from sale of business —  750  Additions to intangible assets including costs to obtain or renew permits (777) (1,868) Purchases of available-for-sale securities (45,622) (55,318) Proceeds from sale of available-for-sale securities 50,318  71,695  Net cash used in investing activities (200,742) (730,670) Cash flows (used in) from financing activities: Change in uncashed checks (2,767) (1,868) Tax payments related to withholdings on vested restricted stock (10,456) (4,599) Repurchases of common stock (67,001) (10,215) Proceeds from employee stock purchase plan 3,360  —  Deferred financing costs paid —  (8,148) Payments on finance leases (16,754) (11,491) Principal payments on debt (7,551) (7,551) Proceeds from issuance of debt, net of discount —  499,375  Net cash (used in) from financing activities (101,169) 455,503  Effect of exchange rate change on cash 5,260  (2,133) Decrease in cash and cash equivalents (87,006) (42,706) Cash and cash equivalents, beginning of period 687,192  444,698  Cash and cash equivalents, end of period $ 600,186  $ 401,992  Clean Harbors • 42 Longwater Drive • PO Box 9149 • Norwell, Massachusetts 02061-9149 • 800.282.0058 • www.cleanharbors.com Supplemental information: Cash payments for interest and income taxes: Interest paid $ 76,570  $ 74,079  Income taxes paid, net of refunds 64,534  70,307  Non-cash investing activities: Property, plant and equipment accrued 25,156  28,315  ROU assets obtained in exchange for operating lease liabilities 34,867  49,420  ROU assets obtained in exchange for finance lease liabilities 57,802  45,174  Supplemental Segment Data (in thousands) Three Months Ended Revenue June 30, 2025 June 30, 2024 Third-Party Revenues Intersegment Revenues (Expenses), net Direct Revenues Third-Party Revenues Intersegment Revenues (Expenses), net Direct Revenues Environmental Services $ 1,330,059  $ 21,976  $ 1,352,035  $ 1,297,298  $ 12,085  $ 1,309,383  Safety-Kleen Sustainability Solutions 219,706  (21,976) 197,730  255,322  (12,085) 243,237  Corporate 89  —  89  99  —  99  Total $ 1,549,854  $ —  $ 1,549,854  $ 1,552,719  $ —  $ 1,552,719  Six Months Ended Revenue June 30, 2025 June 30, 2024 Third-Party Revenues Intersegment Revenues (Expenses), net Direct Revenues Third-Party Revenues Intersegment Revenues (Expenses), net Direct Revenues Environmental Services $ 2,537,097  $ 24,051  $ 2,561,148  $ 2,458,577  $ 23,316  $ 2,481,893  Safety-Kleen Sustainability Solutions 444,521  (24,051) 420,470  470,636  (23,316) 447,320  Corporate 186  —  186  201  —  201  Total $ 2,981,804  $ —  $ 2,981,804  $ 2,929,414  $ —  $ 2,929,414  Three Months Ended Six Months Ended Adjusted EBITDA June 30, 2025 June 30, 2024 June 30, 2025 June 30, 2024 Environmental Services $ 376,194  $ 359,915  $ 650,785  $ 624,390  Safety-Kleen Sustainability Solutions 38,313  51,476  66,565  81,176  Corporate (78,270) (83,575) (146,259) (147,655) Total $ 336,237  $ 327,816  $ 571,091  $ 557,911  Clean Harbors • 42 Longwater Drive • PO Box 9149 • Norwell, Massachusetts 02061-9149 • 800.282.0058 • www.cleanharbors.com