Heritage-Crystal Clean provides parts cleaning, containerized waste management, used oil collection, wastewater vacuum services, antifreeze recycling, field services. Co. operates its business through its segments: Environmental Services, which consists of its parts cleaning, containerized waste management, wastewater vacuum, antifreeze, and field services; and Oil Business, which consists of used oil collection activities, re-refining activities, oil filter removal and disposal services, and the sale of recycled fuel oil. Via its re-refining process, Co. recycles used oil into lubricant base oil and other products, and Co. is a supplier to firms that produce and market finished lubricants.