U.S. Bankruptcy Court Expected to Approve Sale of Safety-Kleen's Chemical Services Division to Clean Harbors.

Business Editors

BRAINTREE, Mass.--(BUSINESS WIRE)--June 18, 2002

Combined Company Will Be North America's Largest Operator of

Hazardous Waste Facilities

Clean Harbors, Inc. (NASDAQ: CLHB), a leading provider of environmental services throughout the United States and Puerto Rico, announced that the U.S. Bankruptcy Court in Delaware has overruled the objections of Onyx North America, to the sale of the assets of the Chemical Services Division (SK/CSD) to Clean Harbors.

A renewed bid submitted late Friday by Onyx North America was determined by Safety-Kleen not to be a higher or better bid than that of Clean Harbors. Accordingly, Safety-Kleen reported to the Court that Clean Harbors had submitted the only "qualified" bid, and requested that the Court issue an order approving the sale. The Court rejected Onyx's bid and is expected to rule on two additional, technical objections to the sale at a hearing today at 3:30 p.m. and also is expected to formally award the sale of the SK/CSD assets to Clean Harbors, Inc.

Alan S. McKim, Chairman and CEO of Clean Harbors, stated, "We are delighted with the Court's action yesterday and look forward to the sale of the SK/CSD assets to Clean Harbors. Since entering into the definitive agreement with Safety-Kleen on February 22, we have worked diligently to establish a comprehensive integration process that will efficiently join the operations and employees of CSD with the operations and employees of Clean Harbors. I am confident that through the efforts of the dedicated employees of both organizations, we will realize our goal of transitioning the CSD into the Clean Harbors network to become the most cost competitive company with the broadest range of services in the industry."

On February 22, 2002, Clean Harbors signed a definitive agreement to acquire SK/CSD, one of the nation's largest environmental services companies, for $46.3 million in cash and the assumption of environmental liabilities valued at approximately $265 million. The transaction, which is expected to close in the third-quarter of 2002, will make Clean Harbors the largest operator of hazardous waste facilities in North America, including a significant presence in Canada. The combined company is expected to have annualized revenue of approximately $750 million, approximately 4,400 employees and 38,000 customers including a vast majority of the Fortune 500.

About Clean Harbors, Inc.

Clean Harbors, Inc. through its subsidiaries provides a wide range of environmental and waste management services to a diversified customer base including a majority of the Fortune 500 companies, thousands of smaller private entities and numerous governmental agencies. Within its national footprint, the Company currently has service and sales offices located in 26 states and Puerto Rico, and operates 11 waste management facilities strategically located throughout the country. For more information, visit our Website at 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, and involve risks and uncertainties. These forward-looking statements are generally identifiable by use of the words "believes," "expects," "intends," "anticipates," "plans to," "estimates," "projects," or similar expressions. These forward-looking statements are subject to certain risks and uncertainties that could cause actual results to differ materially from those reflected in these forward-looking statements. Readers are cautioned not to place undue reliance on these forward-looking statements, which reflect management's opinions only as of the date hereof. The Company undertakes no obligation to revise or publicly release the results of any revision to these forward-looking statements. Information on the potential factors that could affect the Company's actual results of operations is included in its filings with the Securities and Exchange Commission, including but not limited to its Annual Report on Form 10-K for the fiscal year ended December 31, 2001.