Clean Harbors to Announce First-Quarter 2007 Results on May 9

Date: April 24, 2007

Source: Clean Harbors, Inc.

Clean Harbors, Inc. (Nasdaq: CLHB), the leading provider of environmental and hazardous waste management services throughout North America, will host its first-quarter 2007 conference call on Wednesday, May 9, 2007 at 9:00 a.m. ET.

On the call, Chairman, President and Chief Executive Officer Alan S. McKim and Executive Vice President and Chief Financial Officer James M. Rutledge will discuss Clean Harbors' financial results, business outlook and growth strategy.

Those who wish to listen to the first-quarter 2007 conference call webcast 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) 407-5790 or (201) 689-8328 prior to the start of the call. If you are unable to listen to the live call, the webcast will be archived on the Company's website.

About Clean Harbors, Inc.

Clean Harbors, Inc. 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 325 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 36 U.S. states, six Canadian provinces, Mexico and Puerto Rico. For more information, visit www.cleanharbors.com.

Contacts
Clean Harbors, Inc.
James M. Rutledge, 781-792-5100
Executive Vice President and Chief Financial Officer
InvestorRelations@cleanharbors.com.

or

Clean Harbors, Inc.
Bill Geary, 781-792-5130
Executive Vice President and General Counsel

or

Sharon Merrill Associates, Inc.
Jim Buckley, 617-542-5300
Executive Vice President
clhb@investorrelations.com.

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