Cross-State Air Pollution Rule and Section 126 Petitions

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Why it Matters

States rely on the Cross-State Air Pollution Rule (CSAPR) to protect their residents’ health by reducing smog and soot pollution from upwind sources in other states.

Current Status

Lawsuits continue over the Federal Implementation Plan (FIP) and Phase 2 emissions budgets for CSAPR. Meanwhile, downwind states seek deeper cuts in pollution from out-of-state sources. Connecticut, Delaware, and Maryland have sued the Environmental Protection Agency (EPA) for failure to act on their section 126 petitions.


A downwind state can file a section 126 petition asking the EPA to regulate pollution from sources in another state, when that pollution is impairing interstate air quality. EPA has 60 days to respond to a section 126 petition. If EPA determines action is necessary, the polluting state must address the emissions in their State Implementation Plan (SIP). Otherwise a Federal Implementation Plan (FIP) will assign emissions limits. Section 126 petitions prompted EPA to address interstate air pollution across many upwind states in 2005, in the form of the Clean Air Interstate Rule (CAIR).

On August 8, 2011 EPA finalized CSAPR, which replaced CAIR. Both rules were designed to protect interstate air quality. CSAPR regulates nitrogen oxides (NOx), sulfur dioxide (SO2), ozone, and particulate matter. States have “budgets” for these air pollutants and may choose where to find the emissions reductions, as long as the state stays below its budget.

After several legal challenges, EPA began implementing the rule; Phase 1 began on January 1, 2015 and Phase 2 was scheduled to begin on January 1, 2017. Emissions limits become stricter for some states in Phase 2.

Several downwind states seek deeper cuts. On June 1, 2016 Connecticut filed a section 126 petition, asking EPA to curb emissions from the Brunner Island coal plant in Pennsylvania.

On July 7, 2016 Delaware filed its first section 126 petition which asked EPA to curb emissions from the Brunner Island coal plant.

On July 25, 2016 EPA extended the timeline for responding to Connecticut’s petition to January 25, 2017.

On August 9, 2016 Delaware filed its second section 126 petition which asked EPA to curb emissions from the Harrison coal plant in West Virginia.

On August 23, 2016 EPA extended its timeline for responding to the first Delaware petition to March 5, 2017

On September 27, 2016 EPA extended its timeline for responding to the second Delaware petition to April 7, 2017.

On October 26, 2016 EPA published a Federal Implementation plan (FIP) for states that had not incorporated CSAPR into their SIP. EPA also adjusted some of the Phase 2 NOx limits. This companion rule to CSAPR was effective December 26, 2016.

On November 10, 2016 Delaware filed a third section 126 petition asking EPA to address pollution drifting into that state from the Homer City coal plant in Pennsylvania.

On November 16, 2016 Maryland filed a section 126 petition, asking EPA to address pollution drifting into that state from 36 coal plants located in Indiana, Kentucky, Ohio, Pennsylvania, and West Virginia.

On November 22, 2016 16 lawsuits were filed to challenge the October 26, 2016 rule. The consolidated case is styled Wisconsin v. EPA, No. 16-406.

On November 28, 2016 Delaware filed a fourth petition, this time asking EPA to address pollution from the Conemaugh coal plant in Pennsylvania.

On December 16, 2016 EPA extended its timeline for responding to Delaware’s third (Homer City) petition and Maryland’s petition by six months, to July 9, 2017 (DE) and July 15, 2017 (MD).

On January 19, 2017 NY, RI, NH, VT, MA, and MD filed a motion to intervene in Wisconsin v. EPA, supporting EPA’s October 26, 2016 actions.

Trump Era

On January 23, 2017, EPA extended the deadline on Delaware’s fourth (Conemaugh) petition to August 3, 2017.

On February 24, 2017 President Trump signed the Regulatory Reform Executive Order directing EPA to “evaluate existing regulations… and make recommendations to the agency head regarding their repeal, replacement, or modification…). EPA may review this rule under that broad directive.

On March 24, 2017, Delaware sued EPA over the extension of the deadline to respond to its petition regarding the Conemaugh coal plant. Delaware v. EPA, No. 2:17-1099 (D.C. Cir.).

Environmental groups wrote Administrator Pruitt on April 25, 2017, requesting that he grant the pending section 126 Petitions.

On May 17, 2017 Connecticut sued EPA for failure to respond to its petition on the Brunner coal plant in Pennsylvania. – Connecticut V. Pruitt et al., No. 3:17-00796.

On July 20, 2017 Maryland’s Department of the Environment sent a 60-day notice letter to EPA announcing it intends to sue for EPA’s failure to respond to its section 126 petition by the July 15, 2017 deadline.

On September 27, 2017 Maryland sued EPA for failure to respond to its petition.

On January 2, 2018 Delaware gave EPA notice it intends to sue EPA over its failure to address Delaware’s four section 126 petitions.

On April 9, 2018 EPA issued a Notice of Final action rejecting Connecticut’s Brunner coal plant petition, saying it was “denying the petition based on the conclusion that Connecticut has not demonstrated and the EPA has not determined that the Brunner Island facility emits or would emit pollution in violation of the good neighbor provision with respect to the 2008 ozone NAAQS.” EPA had issued a proposed rejection in February.

For more information

For more on the history of CSAPR see its entry in the Columbia University Sabin Center for Climate Change Law’s database. Also see Sabin’s Climate Deregulation Tracker for additional updates.

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