In 1976, Congress enacted the Resource Conservation and Recovery Act, an amendment to the Solid Waste Disposal Act of 1965, which called for regulation by the Environmental Protection Agency (EPA) of solid and hazardous waste disposal. The petitioner bares the responsibility for proving the waste is not hazardous based on the constituents for which it was originally listed; EPA must determine if the waste is hazardous for other reasons. EPA must have reasonable basis for requesting additional information or denying a petition. EPA transporter regulations, set forth in 40 CFR Part 263, deal primarily with manifest tracking and discharge cleanup. Large and small quantity generators cannot treat, store, dispose of, transport, or offer for transportation, hazardous waste without having received an EPA Identification number. Toxic Substances Control Act was enacted in large part due to the discovery of widespread contamination by polychlorinated biphenyls (PCB) and the EPA's lack of regulatory tools to control PCB material.