One Rock Capital Partners, LLC (together with its affiliates, “One Rock”), a value-oriented, operationally focused private equity firm, today announced that it has entered into a definitive agreement to sell EnviroServe Inc. and its related affiliates (collectively, “EnviroServe” or the “Company”) to Clean Harbors, Inc. (“Clean Harbors”) (NYSE: CLH) for $470 million. The transaction is expected to close in the second half of 2026, subject to regulatory approval and other customary conditions.

EnviroServe is a provider of environmental and waste management services, with an extensive service offering spanning remediation, rail services, industrial cleaning and emergency response, as well as hazardous and non-hazardous waste transportation and processing. The Company serves customers across a wide variety of end markets from a strategic network of branches, including 10-day transfer facilities, waste solidification facilities and railcar cleaning locations.

“We acquired EnviroServe, a high-quality, people-driven business with a strong team, loyal customers and attractive growth opportunities, through a carve-out from Savage Companies and built it into a successful standalone business. Under our ownership, we have expanded EnviroServe’s service capabilities through organic growth, new greenfield locations and add-on acquisitions. We believe this transaction with Clean Harbors positions the Company for continued growth as part of one of the world’s leading environmental services companies,” said Tony W. Lee, Managing Partner at One Rock.

Eric Gerstenberg, Co-CEO of Clean Harbors, noted, “We are excited to welcome EnviroServe’s strategic footprint, talented team and loyal customers to Clean Harbors. EnviroServe is a strong strategic and cultural fit with our Technical Services and Field Services businesses and the combination of the two businesses will result in new opportunities for EnviroServe’s team members.”

ABOUT ONE ROCK CAPITAL PARTNERS, LLC

One Rock makes controlling investments in companies with potential for growth and operational improvement using a rigorous approach that utilizes highly experienced Operating Partners to identify, acquire and enhance businesses in select industries. The involvement of these Operating Partners affords One Rock the ability to conduct due diligence and consummate acquisitions and investments in all types of situations, regardless of complexity. One Rock works collaboratively with company management and its Operating Partners to develop a comprehensive business plan focused on growing the enterprise and its profitability to enhance long-term value.

For more information, visit www.onerock.com.

ABOUT ENVIROSERVE

EnviroServe helps customers manage their most complex waste streams safely and in full regulatory compliance. Serving approximately 2,400 customers across a broad range of end markets, the Company has built its reputation on a disciplined safety culture, deep and long-tenured customer relationships and a well-invested operating footprint spanning the United States. EnviroServe combines the responsiveness of a regional operator with the capabilities and reach of a national platform, supporting customers as they navigate increasingly complex environmental and regulatory demands. For more information, visit www.enviroserve.com.

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