Clean Harbors Exceeds Expectations with Record Second Quarter Revenues and Profits

Date: August 8, 2006

Source: Clean Harbors, Inc.

Company Exceeds Revenue and EBITDA Guidance

Clean Harbors, Inc. ("Clean Harbors") (NASDAQ: CLHB), the leading provider of environmental and hazardous waste management services throughout North America, today announced financial results for the second quarter and six months ended June 30, 2006.

For the second quarter of 2006, Clean Harbors reported a $25.7 million increase in revenue to $199.6 million, up 15 percent from $173.9 million reported in the second quarter of 2005. Income from operations rose 24% to $17.8 million from $14.4 million in the second quarter of 2005. Net income attributable to common stockholders was $11.3 million, or $0.55 per diluted share, for the second quarter of 2006. This compares with $7.3 million, or $0.43 per diluted share, in the same period of 2005.

EBITDA (see description below) increased 17 percent to $28.3 million in the second quarter of 2006, from $24.2 million for the quarter ended June 30, 2005.

Comments on the Second Quarter

"Clean Harbors delivered a record-setting performance in the second quarter," stated Alan S. McKim, Chairman and Chief Executive Officer. "We surpassed our revenue and EBITDA guidance through a combination of targeted growth initiatives and a continued focus on cost containment. Our top-line grew by 15% year-over-year as a result of steady execution in both our Technical Services and Site Services businesses. We increased our EBITDA margin to 14.2 percent in the quarter despite one-time expenses related to the move of our corporate headquarters to Norwell and costs associated with the proposed acquisition of Teris L.L.C."

"Within Technical Services, our ability to win large-scale facility projects drove substantial volumes to our disposal facilities," McKim said. "Utilization at our incineration facilities, which includes the expansion we recently implemented at our Deer Park location, was greater than 90 percent. Our momentum in the quarter was even more evident in our landfill business, where volumes increased more than 75% from the same period in 2005."

"Site Services also was a key contributor in the quarter," McKim said. "Along with a steady performance from our branch office locations, we secured approximately $3 million from several small-scale emergency response projects, and $800,000 from residual emergency response work related to the Gulf Coast hurricanes."

Non-GAAP Second-Quarter Results
Clean Harbors reports EBITDA results, which are non-GAAP financial measures, as a complement to results provided in accordance with accounting principles generally accepted in the United States (GAAP) and believes that such information provides additional useful information to investors since the Company's loan covenants are based upon levels of EBITDA achieved. The Company defines EBITDA in accordance with its existing credit agreement, as described in the following reconciliation showing the differences between reported net income and EBITDA for the second quarter and first six months of 2006 and 2005 (in thousands):

Business Outlook and Financial Guidance

"We enter the second half of 2006 with significant momentum in several areas of our business," McKim said. "We have a healthy pipeline of large-scale projects to feed our disposal facilities. Within Site Services, the strength of the Clean Harbors brand continues to grow based on our responsiveness, reliability and extensive portfolio of service offerings. We expect to add two branch locations in the third quarter to support our organic growth. On the cost side, we will continue to pursue our ongoing cost-reduction initiatives, including our focus on internalizing transportation and utilizing our rail assets."

Based on its second-quarter results and current market conditions, the Company expects revenues for the third quarter of 2006 to be in a range of $190 million to $195 million, and EBITDA to be in the range of $28 million to $30 million. This guidance does not include any contribution from the proposed Teris acquisition.

Teris Acquisition

In early May, Clean Harbors announced it had signed a definitive agreement to acquire Teris L.L.C., an environmental services company based in Dallas, Texas with an incinerator in El Dorado, Arkansas and a transportation, storage and disposal facility in Wilmington, California. Under the terms of the agreement, Clean Harbors will acquire all of the membership interests in Teris for approximately $52.7 million in cash from SITA U.S.A., Inc., a subsidiary of Suez Environnement, S.A., a French corporation. Clean Harbors plans to fund the purchase price from existing cash and a term loan under its existing credit agreement. The acquisition is subject to customary closing conditions, and Clean Harbors currently expects the acquisition to close during the third quarter.

"Following the closing of the transaction, we will immediately begin the integration process, which we expect to complete by year-end," concluded McKim. "We are excited about this acquisition as Teris' operations are an ideal complement to our existing network of disposal facilities."

Conference Call Information

Clean Harbors will conduct a conference call for investors to discuss the information contained in this news release today, Tuesday, August 8 at 9:00 a.m. (ET). Investors who want to hear a webcast of the call should log onto www.cleanharbors.com and select "Investor Relations." In addition, if you are unable to listen to the live webcast, the call will be archived on the investor section of the website.

Those who wish to listen to the second-quarter 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 (800) 289-0494 or (913) 981-5520 (confirmation code: 8892444) 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 48 waste management facilities, including nine landfills, five incineration locations and seven wastewater treatment centers, the Company provides essential services to more than 45,000 customers, comprising more than 175 Fortune 500 companies, thousands of smaller private entities and numerous 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.

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