top of page

More Air Quality Exceedances for Mon Valley, Allegheny County on Pace to Exceed 2017 H2S Numbers

Updated: Mar 29



That makes 29 exceedances of the H2S standard in the past six months at Allegheny County Health Department’s air quality monitor in Liberty borough. Hydrogen sulfide is a colorless gas recognizable by its rotten egg odor. 


To put those numbers into perspective: There were just 25 exceedances in all of 2020 and 36 in 2019.


“We are now on pace for 59 exceedances this year, which would equal 2017’s total,” GASP staff attorney Ned Mulcahy explained. “It’s difficult to understate how bad exceeding 2017 would be historically: In only four of the past 22 years have there been 60 or more exceedances of the 24-hour h2s standard at Liberty.”


GASP is again calling on ACHD to publicly address these mounting exceedances. Residents are regularly afflicted by the onslaught of odors and deserve to know what’s going on at U.S. Steel’s Clairton Coke Works to cause the issue, and what the department is doing to hold the company responsible.


There has been no update regarding the April 1 notice of violation (NOV) issued to the company by ACHD for prior exceedances of the hydrogen sulfide ambient air quality standard at the Liberty monitor.  


That NOV covers 25 exceedances 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 from December 2020 through March 2021.


“The health department can’t keep residents in the dark,” GASP Executive Director Rachel Filippini said. “They not only need to provide an update but also what the plan is for improving the situation.”

Source: ACHD 2019 Air Quality Annual Report


bottom of page