EPA published a final rule that reaffirms the legal backing for the Mercury and Air Toxics Standards (MATS) for power plants. The 2012 MATS rule set standards for power plants’ emissions of mercury, acid gasses, and other air pollutants. In order to issue MATS, EPA must first find that these regulations are “appropriate and necessary” under the Clean Air Act. In 2020, the Trump EPA revoked that underlying finding. This final rule responds to the Biden EO 13990 and undoes that 2020 rule, stating that it was predicated on a “fundamentally flawed interpretation of the Clean Air Act.” EPA previously estimated that, between 2010 and 2017, MATS reduced power plant mercury emissions by 86%, acid gas emissions by 96%, and non-mercury metal emissions by 81%. Preserving this rule will prove particularly beneficial to vulnerable communities located near power plants and that are most susceptible to those plants’ air pollution. The rule does not change the current emission standards but it ensures the continuation of current public health protections.