On November 15, 2016, the Environmental Protection Agency (EPA) approved 45 and disapproved 143 human health criteria (HHC) submitted by the State of Washington and, on November 26, 2016, issued a final rule that promulgated 144 federal HHC applicable to Washington's waters. The EPA's final rule took effect on December 28, 2016. In response to a stakeholder petition, the EPA reconsidered its 2016 partial disapproval, and on May 10, 2019, the EPA approved certain HHC that the Agency had previously disapproved. In light of this decision, the Federal standards are no longer necessary, and on August 6, 2019, the EPA initiated a notice and comment process to withdraw the corresponding federally promulgated HHC. The EPA finalized this rule.