Clean Harbors is the leading provider of environmental and industrial services in North America, handling hazardous and non-hazardous waste collection, treatment and disposal (including incineration and landfills), field and emergency response services, industrial cleaning, and, through Safety-Kleen, used-oil collection and re-refining into lubricants. Incorporated in Massachusetts in 1980 and headquartered in Norwell, it is listed on the NYSE (CLH), reported 2025 revenue of $6.03 billion and had about 22,600 active employees at the end of 2025.