On Monday, EPA’s final supplemental finding to its Mercury and Air Toxics Standards (MATS) in response to Michigan v. EPA was published. EPA concludes that consideration of cost does not change its earlier decision that regulation of hazardous air pollutants from coal- and oil-fired electric generating units is appropriate and necessary. EPA had proposed this supplemental finding last fall after the Supreme Court found that EPA erred in not taking costs into account in the rule and directed EPA to consider costs, including cost of compliance, before deciding whether the regulation is appropriate and necessary under Section 112 of the Clean Air Act.
EPA notes that looking at different cost metrics—historical annual revenues, annual capital expenditures, and impacts on retail electricity prices—the cost of complying with MATS is “within the range of historical variability.” EPA found that no information submitted during the comment period on the supplemental finding causes it to conclude otherwise. This supplemental finding is now eligible for judicial review as described in the notice.