As part of EPA's continuing efforts to implement the Frank R. Lautenberg Chemical Safety for the 21st Century Act, which amended the Toxic Substance Control Act (TSCA) with immediate effect upon its enactment on June 22, 2016, EPA is developing a final rule to implement TSCA section 6(b)(1). TSCA section 6(b)(1), as amended, requires that EPA promulgate a final rule within 1 year of enactment to establish a risk-based screening process, including criteria for designating chemical substances as high-priority substances for risk evaluations or low-priority substances for which risk evaluations are not warranted at the time. As required by TSCA, the process to designate the priority of chemical substances must include a consideration of the hazard and exposure potential of a chemical substance or a category of chemical substances (including consideration of persistence and bioaccumulation, potentially exposed or susceptible subpopulations and storage near significant sources of drinking water), the conditions of use or significant changes in the conditions of use of the chemical substance, and the volume or significant changes in the volume of the chemical substance manufactured or processed.