2019-00936: National Emission Standards for Hazardous Air Pollutants: Coal- and Oil-Fired Electric Utility Steam Generating Units-Reconsideration of Supplemental Finding and Residual Risk and Technology Review

Summary

The Environmental Protection Agency (EPA) is proposing a revision to its response to the U.S. Supreme Court decision in Michigan v. EPA which held that the EPA erred by not considering cost in its determination that regulation under section 112 of the Clean Air Act (CAA) of hazardous air pollutant (HAP) emissions from coal- and oil- fired electric utility steam generating units (EGUs) is appropriate and necessary. 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 HAP emissions from coal- and oil-fired EGUs, thereby reversing the Agency's prior conclusion under CAA section 112(n)(1)(A) and correcting flaws in the Agency's prior response to Michigan v. EPA. We further propose 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. We are soliciting comment, however, on whether the EPA has the authority or obligation to delist EGUs from 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). The EPA is also proposing the results of the residual risk and technology review (RTR) of the NESHAP that the Agency 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, we are 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.

The agency’s own summary, as published.

What this changes

Amends 1 part of the Code of Federal Regulations — the standing rules this notice rewrites.

• 40 CFR 63 National Emission Standards for Hazardous Air Pollutants for Source Categories