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April Ends With Three More Air Quality Exceedances in the Mon Valley

Updated: Mar 27

April ended with three more H2S exceedances in the Mon Valley.

Hydrogen sulfide (or H2S) is a colorless gas most commonly recognized by its “rotten egg” smell.

The average concentration of H2S at the Liberty monitor on both Tuesday and Wednesday was 0.007 ppm, according to preliminary health department data. The state 24-hour standard is 0.005 ppm. There was also an exceedance at the North Braddock monitor Wednesday, with a 24-hour concentration of 0.010 ppm – twice the state standard.

That made nine H2S exceedances at the Liberty monitor and three at North Braddock last month – exceedances that come in the wake of a Notice of Violation issued by ACHD to U.S. Steel regarding H2S emissions.

The NOV issued on April 1 covers 25 exceedances that occurred in 2020 and seven in the first quarter of 2021 at the Liberty monitor. 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.

The notice is the first step for any enforcement action – including civil penalties of up to $25,000 per violation per day – for air pollution sources. 

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

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