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New Designated Non-Attainment Area for SO2 in Western PA? That’s What EPA's Proposing - But is it Too Late to Make a Difference?

Updated: Feb 21

The U.S. Environmental Protection Agency (EPA) earlier this month announced a proposal that - if approved - would mean four municipalities in our area would no longer meet a national air quality standard for sulfur dioxide (SO2), a harmful air pollutant emitted from fossil fuel combustion and other industrial processes. 

Specifically, the EPA is proposing to redesignate Lower Yoder Township in Cambria County and St. Clair Township, Seward Borough, and New Florence Borough in Westmoreland County as being in nonattainment for the one-hour 2012 National Ambient Air Quality standard (NAAQS) for SO2.  

Sound a little like word soup? We get it. Here’s why this is kind of a big deal:

EPA’s proposed redesignation will create a nonattainment area that is separate from, but adjacent to, an existing SO2 nonattainment area that consists of all of Indiana County, as well as Plum Creek Township, South Bend Township, and Elderton Borough in Armstrong County.  

In an interesting about face, EPA’s proposed redesignation is based in part on air quality modeling that environmental groups submitted to EPA in 2018 based on emissions data from 2013 through 2018. EPA now admits that it did not fully consider this data in 2020 when it determined that the proposed new nonattainment area was either “unclassifiable” or “attainment/unclassifiable.”  That data showed that the proposed new non-attainment area suffered from levels of SO2 pollution that exceeded the NAAQS.  

A little bit of background on process and some of those technical terms: The Clean Air Act requires EPA to designate areas that do not meet a NAAQS as nonattainment for that NAAQS.  

Once an area has been designated as nonattainment, the state in which it lies must develop what’s known as a State Implementation Plan (SIP) that demonstrates the area will attain the NAAQS within five years of EPA’s designation.  

“A SIP for a nonattainment area is typically based on new emission limits for sources of pollution but may also be based on the reduction of pollution due to equipment upgrades, plant retirements, or the like,” GASP senior attorney John Baillie said.

In Western Pennsylvania, the most significant sources of sulfur dioxide pollution are large facilities that burn coal. Until relatively recently, the already-existing and proposed SO2 nonattainment area in Indiana and Armstrong Counties was home to four power plants that burned coal and contributed to locally high levels of SO2 pollution:  

  • Keystone Generating Station in Plum Creek Township, Armstrong County

  • Conemaugh Generating Station in West Wheatfield Township, Indiana County

  • Homer City Generating Station in Center Township, Indiana County and 

  • Seward Generating Station in East Wheatfield Township, Indiana County 

The SO2 emitted by those facilities was the principal cause of both the existing and proposed new nonattainment designations. But note: Homer City ceased operations in mid-2023, and Keystone and Conemaugh are scheduled to cease operations by no later than 2028. It is logical to expect that attainment will follow once such large sources of SO2 cease emitting.

“It is entirely possible that three of the four large sources of SO2 emissions that impact that proposed new nonattainment area will be shut down before the date by which the area must finally attain the SO2 NAAQS,” Baillie explained.  “In that case, no additional controls or measures may need to be added to Pennsylvania’s SIP. The only real result of EPA’s eleventh-hour about-face on modeling and redesignation of the new nonattainment area will have been to increase paperwork for itself and DEP.”

Editor’s Note: GASP continues to follow this issue closely. We will keep you posted.

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