Heritage-Crystal Clean, Inc, through its subsidiary, Heritage-Crystal Clean, LLC, provides parts cleaning, hazardous and non-hazardous waste, and used oil collection services to small and mid-sized customers in the industrial and vehicle maintenance sectors in North America. It operates through two segments, Environmental Services and Oil Business. The Environmental Services segment offers parts cleaning, containerized waste management, wastewater vacuum, antifreeze recycling, emergency and spill response, and industrial and field services. The Oil Business segment engages in the collection of used oil, the sale of recycled fuel oil, and used oil filter removal and disposal activities, as well as the re-refining of used oil into lubricant base oil and other products. The company also collects and disposes wastewater. As of December 31, 2022, it operated through 105 branches serving approximately 104,000 customer locations. Heritage-Crystal Clean, Inc. was founded in 1999 and is headquartered in Hoffman Estates, Illinois. As of October 17, 2023, Heritage-Crystal Clean, Inc was taken private.