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Watchdog Report: Another Weekend, Another Pair of Air Quality Exceedances for Mon Valley

Updated: Mar 28


It was another weekend of poor air quality for Mon Valley residents: The Liberty-Clairton area (again) had the worst AQI in the country Saturday morning when it soared into the red, unhealthy-for-all range. 


Allegheny County also tallied two more air quality exceedances over the weekend, when concentrations of hydrogen sulfide exceeded Pennsylvania’s 24-hour average standard of 0.005 ppm at the Liberty monitor Friday (0.007 ppm) and Saturday (0.012 ppm).


The latest bout of poor air quality pushed exceedances at the Liberty monitor to 22 so far this year. By contrast, there were 25 such exceedances at the Liberty monitor in ALL of 2020.

Hydrogen sulfide is a colorless gas most commonly recognized by its “rotten egg” smell.


This puts us on track to average at least one H2S violation per week, back to where it was in 2019. Numbers like that suggest air quality in 2020 was anything but typical and calls into question the County’s press release earlier this year that stated air quality was still on track to attain the federal standards in 2020 even without lower levels of pollution due to the pandemic.


This also calls into question what’s been going on at U.S. Steel’s Clairton Coke Works so far in 2021. 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.


The NOV covers 25 exceedances that occurred in 2020 and seven from the first quarter of 2021. The notice is the first step for any enforcement action, including civil penalties of up to $25,000 per violation per day, for sources. 


Eight exceedances of the state’s 24-hour H2S standard that occurred at the North Braddock monitor December 2020 through March 2021 were not included.


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. 


“Since the NOV was issued, there have been 15 more H2S exceedances at Liberty and zero additional information from the health department,” GASP Executive Director Rachel Filippini said. “It’s been nearly two months since the enforcement action was filed, the public deserves an update.”


She continued:


“ACHD has a duty to provide residents with timely public communications regarding extended bouts of unhealthy air quality and how it could impact their health and that of their families,” Filippini said. “We appreciate that the health department has started to address poor air quality in the Mon Valley via social media, but all too often those communications come too late to help residents make decisions that could help mitigate their exposure to unhealthy air.”


Editor’s Note: GASP has submitted a state Right to Know request related to the April 1 NOV and will provide more information if and when it is granted.


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