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Another Weekend, Another H2S Air Quality Exceedance for Mon Valley

Updated: Mar 25

The average concentration yesterday was 0.006 ppm, according to preliminary health department data. The state 24-hour standard is 0.005 ppm. The Sunday H2S exceedance was the sixth so far this month and the 13th so far this year at the Liberty monitor.

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

This most recent exceedance comes in the wake of a Notice of Violation issued by ACHD to U.S. Steel on April 1 regarding H2S emissions.

The NOV covers 25 exceedances that occurred in 2020 and seven in 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.

Since the NOV was issued, there have been six more exceedances of the H2S standard at the Liberty monitor and two at the North Braddock monitor.

U.S. Steel had 14 days to schedule a meeting with ACHD to discuss the NOV before legal may proceed with further enforcement action. No further information about the notice or U.S. Steel’s response is available on the ACHD website.

“Yesterday we heard from so many about how poor the air quality was, how much it impacted their health and quality of life – about headaches and asthma attacks,” GASP Executive Director Rachel Filippini said. “We hope that the health department understands just how awful these bad-air days are to the people who live in the Mon Valley and downwind of it. They deserve clean air, and they also deserve transparency on what ACHD is doing to make that happen. It’s time for the health department to update the public about exactly what it’s doing to remedy this situation.”

While ACHD has committed to providing Mon Valley air quality alerts when levels of fine particulate matter are expected to exceed health-based standards, GASP is again calling on the department to expand that messaging – folks deserve to know when levels of other pollutants like H2S are expected to exceed Pennsylvania’s own air quality standard.” 

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