Clean Harbors, Inc. (“Clean Harbors”) (NYSE: CLH) announced today that it has priced a previously announced private placement of $600 million of Senior Notes due 2021 (the “Notes”). The size of the private placement was increased from the previously announced amount of $550 million. The Notes, which carry an interest rate of 5.125%, were priced at 100.0% of the aggregate principal amount thereof. The transaction is expected to close on or about December 7, 2012, subject to customary closing conditions. Clean Harbors intends to use the net proceeds of the offering, together with the net proceeds of its follow-on offering of 6.0 million shares of common stock, which was priced on November 27, 2012, to finance a portion of the purchase price for Clean Harbors’ previously announced proposed acquisition of Safety-Kleen, Inc. and its subsidiaries and related transaction fees and expenses. The Notes are being offered in the United States to qualified institutional buyers pursuant to Rule 144A under the Securities Act of 1933, as amended (the “Securities Act”), and outside the United States pursuant to Regulation S under the Securities Act. This press release shall not constitute an offer to sell or the solicitation of an offer to buy, nor shall there be any sale of, the Notes in any jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such jurisdiction. The Notes will not be registered under the Securities Act or the securities laws of any other jurisdiction and may not be offered or sold in the United States absent registration or an applicable exemption from registration requirements. 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 Clean Harbors’ proposed acquisition of Safety-Kleen and 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 Clean Harbors’ most recently filed Form 10-K and Form 10-Q. Therefore, readers are cautioned not to place undue reliance on these forward-looking statements. Clean Harbors 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 in the “Investors” section of Clean Harbors’ website.