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 proposed rule to implement TSCA section 8(b)(4)(C). TSCA section 8(b)(4)(C) requires EPA to issue a final rule, within 1 year of EPA's compiling of a list of active substances on the TSCA Inventory pursuant to revised TSCA section 8(b)(4)(A), that establishes a plan to review all claims to protect the specific chemical identities of chemical substances on the confidential portion of the active Inventory. The rule must require all manufacturers or processors asserting Confidential Business Information (CBI) claims for the identities of chemicals on the active Inventory to substantiate those claims in accordance with TSCA section 14 unless the manufacturer or processor already substantiated the claim in a submission to EPA that was subsequently approved during the previous 5-year period. Approved CBI claims will generally be valid for 10 years except as authorized by the statute.