Clean Harbors Completes Acquisition of Ensco Caribe, Inc. in Puerto Rico, and Forms Clean Harbors Caribe, Inc.

Norwell, MA – January 22, 2007 – Clean Harbors, the leading provider of environmental and hazardous waste management services throughout North America, today announced that it has completed the acquisition of Ensco Caribe, Inc., an environmental services and emergency response company based in San Juan, Puerto Rico. Clean Harbors acquired all of the membership interests in Ensco Caribe. Combined with Clean Harbors existing operations in Puerto Rico, the newly acquired entity will be Clean Harbors Caribe, Inc.

“Ensco Caribe’s operations represent an ideal fit with our existing capabilities in Puerto Rico,” said David M. Parry, Executive Vice President, Sales & Service. “Our investment in Ensco Caribe further improves our ability to service our customers on the island and demonstrates our commitment to maintaining the broadest portfolio of service offerings in our industry. We intend to leverage our existing waste collection and disposal capabilities in Puerto Rico and capitalize on the site services and emergency response capabilities of the Caribe operations.”

“The combination of Ensco Caribe with Clean Harbors’ current operations represents an exciting opportunity to provide the full range of environmental services to businesses across Puerto Rico,” added María Teresa Méndez, CEO and President of Ensco Caribe, who will be managing the newly formed Clean Harbors Caribe operations. “We have had an excellent working relationship with Clean Harbors and believe the combination will be a good cultural fit for the two groups. As a result, we expect the integration to be seamless, particularly for our customers.”

Ensco Caribe was a joint venture between Ochoa Industrial Sales Corporation and Teris, LLC. Clean Harbors acquired Teris in August of last year. Ensco Caribe operates a service location in Cataño, Puerto Rico, providing environmental services and dispatching crews and equipment to respond to hazardous material spills and environmental emergencies. Since 1992, Clean Harbors has provided waste transportation and disposal services in Puerto Rico. Its current base of operation is in Barceloneta, Puerto Rico. Clean Harbors Caribe will now provide the full complement of on-site environmental services, waste management and disposal, and emergency response services throughout Puerto Rico.

“The Ensco Caribe acquisition fits squarely with our growth strategy of expanding our geographic footprint and increasing market penetration,” said Parry. “We are pleased to welcome the Ensco Caribe team to the Clean Harbors family. Working together, we believe this transaction will be beneficial to all of the employees and the existing customers of both companies.”

About Clean Harbors

Clean Harbors is North America’s leading provider of environmental and hazardous waste management services. With an unmatched infrastructure of 49 waste management facilities, including nine landfills, six incineration locations and six wastewater treatment centers, the Company provides essential services to over 45,000 customers, including more than 175 Fortune 500 companies, thousands of smaller private entities and numerous federal, state and local governmental agencies. Headquartered in Norwell, Massachusetts, Clean Harbors has more than 100 locations strategically positioned throughout North America in 37 U.S. states, six Canadian provinces, Mexico and Puerto Rico. 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, 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 other than through its various filings with the Securities and Exchange Commission.

A variety of factors beyond the control of the Company may affect the Company’s performance, including, but not limited to:

• The Company’s ability to successfully integrate Teris’ operations and assets into its existing network of services and disposal facilities;
• The Company’s ability to manage the significant environmental liabilities which it assumed in connection with the CSD acquisition;
• The availability and costs of liability insurance and financial assurance required by governmental entities relating to our facilities;
• The effects of general economic conditions in the United States, Canada, Puerto Rico and other territories and countries where the Company does business;
• The effect of economic forces and competition in specific marketplaces where the Company competes;
• The possible impact of new regulations or laws pertaining to all activities of the Company’s operations;
• The outcome of litigation or threatened litigation or regulatory actions;
• The effect of commodity pricing on overall revenues and profitability;
• Possible fluctuations in quarterly or annual results or adverse impacts on the Company’s results caused by the adoption of new accounting standards or interpretations or regulatory rules and regulations;
• The effect of weather conditions or other aspects of the forces of nature on field or facility operations;
• The effects of industry trends in the environmental services and waste handling marketplace; and
• The effects of conditions in the financial services industry on the availability of capital and financing.

Any of the above factors and numerous others not listed nor foreseen may adversely impact the Company’s financial performance. Additional 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, which may be viewed on the Investor portal of the Company’s Web Page at www.cleanharbors.com.

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