On February 8, 2021, the U.S. Environmental Protection Agency (EPA) received a petition seeking a rule reversing EPA’s 1991 Bevill regulatory determination excluding phosphogypsum and process wastewater from phosphoric acid production (process wastewater) from hazardous waste regulation under Subtitle C of the Resource Conservation and Recovery Act (RCRA). The petition also urges EPA to promulgate regulations under RCRA Subtitle C governing the safe treatment, storage, and disposal of phosphogypsum and process wastewater as RCRA hazardous waste. Under Section 21 of the Toxic Substances Control Act (TSCA), Petitioners request that EPA initiate the prioritization process to designate phosphogypsum and process wastewater as high-priority substances for risk evaluation under TSCA Section 6, issue a TSCA Section 4 test rule for disposed phosphogypsum, and issue a significant new use rule (SNUR) under TSCA Section 5 for phosphogypsum used in road construction. In its letter acknowledging receipt of the petition, EPA notes that under TSCA Section 21, EPA has 90 days after the date of filing to grant or deny the petition. If EPA denies the petition, EPA will publish the reasons for such a denial in the Federal Register. For more information, please read the full memorandum.