Exhibit 99.1

Press Release

Clean Harbors Announces Second-Quarter 2020 Financial Results
 

NORWELL, Mass. – August 5, 2020 – Clean Harbors, Inc. (“Clean Harbors”) (NYSE: CLH), the leading provider of environmental and industrial services throughout North America, today announced financial results for the second quarter ended June 30, 2020.

“Our second-quarter results demonstrate the resiliency of our business model and our organization’s ability to effectively respond to a crisis,” said Alan S. McKim, Chairman, President and Chief Executive Officer. “The COVID-19 pandemic forced shutdowns across North America, which began to impact many of our markets and customers. In response, we enacted a comprehensive series of actions, including developing safety protocols to protect our workforce, rapidly reducing costs, lowering our capital spending, partially shutting down work locations, temporarily closing nearly half our re-refinery capacity and launching a comprehensive COVID-19 emergency response service offering.”

Second-Quarter 2020 Results

Revenues were $710.0 million compared with $868.7 million in the same period of 2019. Income from operations was $60.2 million compared with $73.0 million in the second quarter of 2019.

Net income was $29.0 million, or $0.52 per diluted share. This compares with net income of $36.2 million, or $0.65 per diluted share, for the same period in 2019. Adjusted for certain items in both periods, adjusted net income was $28.9 million, or $0.52 per diluted share, for the second quarter of 2020, compared with adjusted net income of $36.9 million, or $0.66 per diluted share, in the same period of 2019. (See reconciliation table below)

Adjusted EBITDA (see description below) was $135.5 million compared with $149.8 million in the same period of 2019.

Clean Harbors • 42 Longwater Drive • PO Box 9149 • Norwell, Massachusetts 02061-9149 • 800.282.0058 • www.cleanharbors.com

Q2 2020 Review

“While overall profitability for the company was lower compared with a year ago, our Environmental Services segment achieved a 17% increase in Adjusted EBITDA, driven in part by our disposal facilities and decontamination work,” McKim said. “Incineration utilization was a robust 87% as we continued to capture high-value waste streams across our network and capitalized on the strong backlog we had entering the quarter. Landfill volumes were down 24% due to the COVID-19 related deferral of some remediation and waste projects, but our base business remained stable. Field Services revenue grew nearly 50% from a year ago as we generated $50 million in pandemic-related work in the quarter. We have now completed more than 7,000 COVID-19 responses. Certain portions of our Environmental Services segment, including Industrial Services and other lines of business, such as household hazardous waste and lab pack, were negatively impacted as a result of the virus outbreak.

“The pandemic also adversely impacted our Safety-Kleen segment as shelter-in-place restrictions imposed early in the quarter substantially lowered vehicle miles driven across much of the U.S. This resulted in a reduction in near-term demand for core offerings in our Safety-Kleen branch network as well as for base oil and finished lubricants in our Safety-Kleen Oil business,” McKim said. “Safety-Kleen revenue was down 30% from a year ago with Adjusted EBITDA declining 41%. Aggressive cost actions enabled us to partly offset lower revenue in this segment. We also significantly raised our charge-for-oil (CFO) rates for used motor oil (UMO) as crude oil prices crashed and demand for our re-refined lube oil products and other outlets for waste oil shuttered.”

Business Outlook and Financial Guidance

“As we enter the second half of 2020, we believe we have positioned ourselves well for the current economic environment,” McKim said. “Within multiple parts of our business, we have seen a measurable recovery from the lows we experienced in April as both the U.S. and Canadian economies reopened in subsequent months. While localized outbreaks have threatened to stall the progress in certain states or regions, we believe that the prudent cost actions we have taken should enable us to weather virus-related slowdowns. In addition, our emergency response business is partially offsetting lost revenue in other parts of our business. We will continue to pursue opportunities for disinfection, decontamination and disposal with impacted customers going forward.

“Within Environmental Services, our recycling and disposal network continues to see a steady flow of waste volumes, with no meaningful decline from most of our large-quantity generators. We are experiencing project delays due to the virus, and some Chemical customers have recently slowed production. While that may limit our high-margin volumes in the short-term, other parts of this segment, including Industrial Services and Technical Services, are expected to ramp up in the second half of this year. Field Services is on track for a strong 2020, with anticipated COVID-related revenue of approximately $100 million for the full year.

“Within Safety-Kleen, we began the third quarter on a positive trajectory, but still remain below prior year levels. The branch business continues to improve as summer-related driving increases demand for our services. We are monitoring the impact of new shelter-in-place mandates, but the recent rise in COVID cases so far has not derailed our recovery in the Safety-Kleen branch business. For Safety-Kleen Oil, we have seen base oil and lubricant demand rebound and we restarted production in July at two of the four re-refineries that we had temporarily closed. We will continue to actively manage our CFO rates to reflect the value of the waste oil and the collection services we are providing.

“Based on the visibility into our business and end markets, we are reestablishing annual guidance. Despite continued economic uncertainties, we are confident that we can achieve these new targets given our market leadership and the actions we have taken in response to the pandemic,” McKim concluded.

Clean Harbors • 42 Longwater Drive • PO Box 9149 • Norwell, Massachusetts 02061-9149 • 800.282.0058 • www.cleanharbors.com

Based on its year-to-date financial performance and current market conditions, for 2020 Clean Harbors expects:

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 since the Company’s loan covenants are based upon levels of Adjusted EBITDA achieved and management routinely evaluates the performance of its businesses based upon levels of Adjusted EBITDA. The Company defines Adjusted EBITDA in accordance with its existing revolving credit agreement, as described in the following reconciliation showing the differences between reported net income and Adjusted EBITDA for the three and six months ended June 30, 2020 and 2019 (in thousands):

This press release includes a discussion of net income and earnings per share adjusted for the loss on sale of businesses, net of tax and the impacts of tax-related valuation allowances as identified in the reconciliations provided below. The Company believes that discussion of these additional non-GAAP measures provides investors with meaningful comparisons of current results to prior periods’ results by excluding items that the Company does not believe reflect its fundamental business performance. The following shows the difference between net income to adjusted net income, and earnings per share to adjusted earnings per share for the three and six months ended June 30, 2020 and 2019 (in thousands, except per share amounts):

Clean Harbors • 42 Longwater Drive • PO Box 9149 • Norwell, Massachusetts 02061-9149 • 800.282.0058 • www.cleanharbors.com

Adjusted Free Cash Flow Reconciliation

Clean Harbors reports adjusted free cash flow, 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 excluding cash impacts of items derived from non-operating activities, less additions to property, plant and equipment plus proceeds from sale and disposal of fixed assets. The Company excludes cash impacts of items derived from non-operating activities such as taxes paid in connection with divestitures and in the current period have also excluded cash paid in connection with the purchase of its corporate headquarters and certain capital improvements to the site as these expenditures are considered one-time in nature. 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.

An itemized reconciliation between net cash from operating activities and adjusted free cash flow is as follows for the three and six months ended June 30, 2020 and 2019 (in thousands):

Clean Harbors • 42 Longwater Drive • PO Box 9149 • Norwell, Massachusetts 02061-9149 • 800.282.0058 • www.cleanharbors.com

Adjusted EBITDA Guidance Reconciliation

An itemized reconciliation between projected GAAP net income and projected Adjusted EBITDA is as follows (in millions):

Adjusted Free Cash Flow Guidance Reconciliation

An itemized reconciliation between projected net cash from operating activities and projected adjusted free cash flow is as follows (in millions):

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 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 201.689.8881 or 877.709.8155 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, energy and manufacturing, 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 North America’s largest re-refiner and recycler of used oil and a leading provider of parts washers and environmental services to commercial, industrial and automotive customers. 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.

Clean Harbors • 42 Longwater Drive • PO Box 9149 • Norwell, Massachusetts 02061-9149 • 800.282.0058 • 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,” “should,” “estimates,” “projects,” “may,” “likely,” or similar expressions. Such statements may include, but are not limited to, statements about future financial and operating results, and other statements that are not historical facts. Such statements are based upon the beliefs and expectations of Clean Harbors’ management as of this date only and are subject to certain risks and uncertainties that could cause actual results to differ materially, including, without limitation, the risks and uncertainties surrounding COVID-19 and the related impact on the Company’s business, and those items identified as “Risk Factors” in Clean Harbors’ most recently filed 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:

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 OPERATIONS

(in thousands, except per share amounts)

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 BALANCE SHEETS

(in thousands)

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)

Clean Harbors • 42 Longwater Drive • PO Box 9149 • Norwell, Massachusetts 02061-9149 • 800.282.0058 • www.cleanharbors.com

Supplemental Segment Data (in thousands)

Clean Harbors • 42 Longwater Drive • PO Box 9149 • Norwell, Massachusetts 02061-9149 • 800.282.0058 • www.cleanharbors.com