On November 16th, EPA proposed an “update” to its Cross-State Air Pollution Rule (CSAPR) ozone season requirements. Starting in 2017, the proposal is intended to reduce summertime emissions of nitrogen oxides (NOx) from power plants in 23 eastern States. The NOx limitations are predicated on reducing interstate air impacts on downwind States’ ability to meet the 2008 75 ppb ozone standard, as well as responding to the July 2015 remand of CSAPR NOx budgets by the United States Court of Appeals for the D.C. Circuit.

The update is based on the Clean Air Act's "good neighbor" provision that requires States to address interstate impacts of air emissions from their sources on downwind States’ ability to meet and maintain air quality standards. If a State contributes “significantly” to adverse impacts in a downwind State, it is obligated to submit a State Implementation Plan (SIP) revision to eliminate the impacts. In this proposal, EPA alleges such adverse impacts from the 23 States and proposes NOx budgets for each in order to reduce or eliminate the “significant” impacts.

On June 30th, EPA issued a final notice determining that a number of states had failed to submit “good neighbor” SIPs for the 2008 standard. The findings set a 2-year deadline for EPA to either approve a revised SIP for each noticed State or impose a Federal plan to meet the “good neighbor” requirement.

EPA notes in the proposal that it is only a partial solution and may not fully eliminate adverse interstate impact, while insisting the proposal would result in significant reductions in interstate ozone-causing emissions. While the proposal focuses on interstate emissions transport the eastern US, EPA is also soliciting comments on whether western States should be included in the rule.

The 23 States included in the proposal include all States east of the Mississippi River except the New England States, South Carolina, Georgia and Florida, and seven States west of the river – Iowa, Missouri, Arkansas, Louisiana, Kansas, Oklahoma, and Texas.