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More Unhealthy Air Quality, Exceedances Pervade Mon Valley – Update on H2S Problem Needed

Updated: Mar 28



The colorless gas is most commonly recognized by its “rotten egg” odor and concentrations exceeded the Pennsylvania 24-hour average standard of 0.005 ppm on both Saturday (0.007 ppm) and Sunday (0.009 ppm) at Allegheny County Health Department’s air quality monitor in Liberty borough.


“There have been 24 H2S exceedances so far this year at Liberty. That’s only one less than in all of 2020, but it’s also worth noting that the first exceedance in 2021 at that monitor didn’t occur until March 3,” GASP staff attorney Ned Mulcahy explained. “In other words, there has been an average of one H2S exceedance every fourth day for the past three months. That’s downright awful.”


The spate of exceedances so far this year begs the question: What is going on at U.S. Steel’s Clairton Coke Works? The Allegheny County Health Department on April 1 issued a Notice of Violation against the company for exceedances of the hydrogen sulfide ambient air quality standard at the Liberty monitor.


That NOV covers 25 exceedances that happened in 2020 and seven more from the first quarter of 2021. It did NOT include eight exceedances of Pennsylvania’s 24-hour H2S standard that occurred at the North Braddock air quality monitor December 2020 through March 2021.


Procedurally, U.S. Steel had 14 days to schedule a meeting with ACHD to discuss the NOV before the department could proceed with further enforcement action. But since the NOV was issued, there have been 17 more H2S exceedances. 


GASP submitted a formal Right to Know request for information related to the NOV and was provided little new information. However, we did receive copies of internal emails showing Allegheny County Chief Executive Rich Fitzgerald is aware of – and concerned about – the problem despite making no public statements about the ongoing air quality issue facing his constituents.


In an email to ACHD Deputy Director of Environmental Health Jim Kelly, the department’s Chief Operating Officer Patrick Dowd wrote:


“The County Executive was clearly frustrated that US Steel could meet the three-year emissions average yet still emit so much PM2.5 that people could be choking in a given set of hours.
He clearly wants to find a way to encourage the company to do the right thing for public health as you and your team pursue the longer term strategies related to regulatory changes.
Once you and your team have conferred, please, let’s you and I talk later today. Thank you, Jim. This work is extremely important, as the County Executive clearly said on the call.”

You can read the entire email here:


GASP is again calling on ACHD and Fitzgerald to provide a substantive update to residents on what is causing the H2S – as well as other air quality issues in the Mon Valley – and what transpired between when the NOV was issued and now.


“The public has had to deal with pervasive rotten egg odors from H2S this entire spring yet has received zero updates from the health department,” GASP Executive Director Rachel Filippini said. “H2S in the Mon Valley is a problem that’s getting worse, not better. It’s well past time for the health department and County Executive Fitzgerald to provide residents with an update on what’s being done to remedy this quality-of-life issue impacting far too many who live in Allegheny County.”



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