As part of EPA's ongoing 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)(4). TSCA section 6(b)(4), as amended, requires that EPA promulgate a final rule within 1 year of enactment to establish EPA's process for evaluating the risk of existing chemical substances and determining whether they present an unreasonable risk of injury to health or the environment, without consideration of costs or other non-risk factors, including an unreasonable risk to a potentially exposed or susceptible subpopulation identified as relevant to the risk evaluation by the Administrator, under the conditions of use.