The Environmental Protection Agency (EPA) is seeking public comment on its proposal to delist coal- and oil-fired electric utility steam generating units (EGUs) from the Clean Air Act (CAA) section 112(c) and rescind (or to rescind without delisting) the National Emission Standards for Hazardous Air Pollutants (NESHAP) for Coal- and Oil-Fired EGUs, commonly known as the Mercury and Air Toxics Standards (MATS).
After considering the cost of compliance relative to the HAP benefits of regulation, the EPA proposes to find that it is not “appropriate and necessary” to regulate hazardous air pollution (HAP) emissions from coal- and oil-fired EGUs, thereby reversing the EPA's prior conclusion under CAA section 112(n)(1)(A) and correcting flaws in the EPA's prior response to Michigan v. EPA. The EPA further proposes that finalizing this new response to Michigan v. EPA will not remove the Coal- and Oil-Fired EGU source category from the CAA section 112(c) list of sources that must be regulated under CAA section 112(d) and will not affect the existing CAA section 112(d) emissions standards that regulate HAP emissions from coal- and oil-fired EGUs.
The EPA is also proposing the results of the residual risk and technology review (RTR) of the NESHAP that the EPA is required to conduct in accordance with CAA section 112. The results of the residual risk analysis indicate that residual risks due to emissions of air toxics from this source category are acceptable and that the current standards provide an ample margin of safety to protect public health. No new developments in HAP emission controls to achieve further cost-effective emissions reductions were identified under the technology review. Therefore, based on the results of these analyses and reviews, the EPA is proposing that no revisions to MATS are warranted. Finally, the EPA is also taking comment on establishing a subcategory for emissions of acid gas HAP from existing EGUs firing eastern bituminous coal refuse.