Exhibit 99.1

Press Release

Clean Harbors Reports Fourth-Quarter
and Year-End 2010 Financial Results

·                  Contributions Across Business Lines Drive Strong Results

·                  Q4 Revenue Increases 20% to $417 Million

·                  Q4 Net Income Up 68%; EBITDA Grows to $70.3 Million

·                  Company Increases 2011 Guidance

Norwell, MA — February 23, 2011 — Clean Harbors, Inc. (“Clean Harbors”) (NYSE: CLH), the leading provider of environmental and energy and industrial services throughout North America, today announced financial results for the fourth quarter and year ended December 31, 2010.

Revenues increased 20% to $417.1 million from $347.0 million in the fourth quarter of 2009, reflecting a strong contribution from both its environmental and energy and industrial businesses. Income from operations increased 54% to $43.0 million from $27.9 million in the fourth quarter of 2009.

Fourth quarter 2010 net income grew to $23.3 million, or $0.88 per diluted share, from $13.9 million, or $0.53 per diluted share, in the fourth quarter of 2009.  EBITDA (see description below) increased to $70.3 million from $52.6 million in the fourth quarter of 2009.

Comments on the Fourth Quarter

“Clean Harbors concluded a successful 2010 with a strong fourth-quarter performance, as we delivered 34 percent growth in EBITDA on a 20 percent increase in revenue,” said Alan S. McKim, Chairman and Chief Executive Officer.  “We experienced a continuation of the favorable industry trends we saw in the third quarter, achieving double-digit growth across a number of key markets including Chemicals, Manufacturing, Oil & Gas, Refineries and Utilities.”

“Both our Environmental business and our Energy and Industrial business generated momentum during the quarter,” McKim said. “Within Environmental, utilization at our incinerators exceeded 93% for the quarter — our highest level of 2010.  In addition, a sharp uptick in projects drove total landfill volumes up by more than 60 percent from the same period of 2009.  Within our Energy and Industrial business, increased investments in Western Canada by major energy companies continued to spark production activity, creating new opportunities for us throughout the region and generating another excellent quarter for our lodging business.”

Full-Year 2010 Results

Revenues for 2010 increased 61% to $1.73 billion from $1.07 billion in 2009.  The Company’s participation in the oil spill response efforts in the Gulf of Mexico and Michigan generated revenues of approximately $253 million in 2010.  Income from operations more than doubled to $211.9 million from $82.1 million in 2009.  2010 net income grew to $130.5 million, or $4.93 per diluted share, from $36.7

42 Longwater Drive · P.O. Box 9149 · Norwell, Massachusetts 02061-9149 · 781.792.5000 · www.cleanharbors.com

million, or $1.47 per diluted share, in 2009.  EBITDA (see description below) doubled to $314.7 million from $157.6 million for 2009.

The Company concluded 2010 with cash and marketable securities of $305.4 million, compared with $235.6 million at December 31, 2009.

Non-GAAP 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 fourth quarter and full year of 2010 and 2009 (in thousands):

Business Outlook and Financial Guidance

“Our outlook remains decidedly positive as we head into 2011.  We are continuing to see indications of the general economic recovery as we maintain an active pipeline of potential new projects within both our Environmental and Energy and Industrial businesses.  We are excited about the prospects for our pending acquisition of Badger Daylighting, and are continuing to evaluate additional strategic acquisition opportunities,” McKim concluded.

Based on fourth-quarter performance, and current market conditions, Clean Harbors is increasing its 2011 annual revenue and EBITDA guidance.  The Company currently expects 2011 revenues in the range of

$1.54 billion to $1.59 billion, up from its previous revenue guidance of $1.52 billion to $1.57 billion.  For 2011, the Company expects EBITDA in the range of $262 million to $270 million, an increase from its previous guidance of $258 million to $267 million.  This guidance is exclusive of any potential future acquisitions, including the Company’s planned purchase of Badger Daylighting.

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.  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.

Investors who wish to listen to the webcast should log onto www.cleanharbors.com/investor_relations.  The live call also can be accessed by dialing 877.709.8155 or 201.689.8881 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

Clean Harbors is the leading provider of environmental, energy and industrial services throughout North America.  The Company serves more than 50,000 customers, including a majority of the Fortune 500 companies, thousands of smaller private entities and numerous federal, state, provincial and local governmental agencies.

Headquartered in Norwell, Massachusetts, Clean Harbors has more than 175 locations, including over 50 waste management facilities, throughout North America in 36 U.S. states, seven Canadian provinces, Mexico and Puerto Rico.  The Company also operates international locations in Bulgaria, China, Singapore, Sweden, Thailand and the United Kingdom.  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.  These forward-looking statements are generally identifiable by use of the words “believes,” “expects,” “intends,” “anticipates,” “plans to,” “estimates,” “projects,” or similar expressions.  Such statements may include, but are not limited to, statements about the Company’s business outlook and financial guidance 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, those items identified as “risk factors” in the

Company’s most recently filed Form 10-K and Form 10-Q. Therefore, readers are cautioned not to place undue reliance on these forward-looking statements.  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, which may be viewed at www.cleanharbors.com/investor_relations.

CLEAN HARBORS, INC. AND SUBSIDIARIES

UNAUDITED CONSOLIDATED STATEMENTS OF INCOME

(in thousands except per share amounts)

CLEAN HARBORS, INC. AND SUBSIDIARIES

UNAUDITED CONDENSED CONSOLIDATED BALANCE SHEETS

ASSETS

(in thousands)

CLEAN HARBORS, INC. AND SUBSIDIARIES

UNAUDITED CONDENSED CONSOLIDATED BALANCE SHEETS

LIABILITIES AND STOCKHOLDERS’ EQUITY

(in thousands)