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Health Department Tracks Down Source of Rotten Egg Hydrogen Sulfide Emissions

Updated: Feb 22

A year ago GASP began urging the Allegheny County Health Department (ACHD) to do more to eliminate violations of the County’s hydrogen sulfide (H2S) standard and the offensive rotten egg odors that go along with those violations.

GASP documented that the H2S standard has been violated on average more than 50 times a year, over the past six years, according to readings from the Liberty Borough monitor in the Mon Valley.

At the ACHD Air Quality Program Criteria Pollutant/Air Monitoring subcommittee meetings, we repeatedly insisted that ACHD staff look into the problem and do more to reduce these illegal emissions. We are pleased to report some progress is occurring.

At a recent meeting of the subcommittee, ACHD provided a preliminary study that compared the frequency and intensity of H2S concentrations with weather conditions and other types of air pollution at the Liberty Borough monitor from 2013-2017.

The study concluded that there was no seasonal trend in the occurrence of high H2S concentrations but there was a daily trend: most of the highest H2S readings occurred between 8 p.m. and 10 a.m. It is likely our region’s frequent atmospheric inversions, which occur at night, are trapping the H2S closer to the ground.

ACHD also concluded that sulfur dioxide (SO2), benzene, and fine particles (PM2.5) appeared to increase with an increase in H2S. These are all pollutants highly associated with coke-making. The study also revealed that most of the highest hourly H2S, SO2, benzene, and PM2.5 readings, at the Liberty monitor, typically came from the south, south-southwest, and southwest—which is in the general upwind direction of U.S. Steel’s Clairton Coke Works.

ACHD concludes that, “Based on location and amount of reported emissions from USS Clairton, it is likely a substantial contributor to the H2S, SO2, benzene, and PM2.5 concentrations.”

Is anyone surprised by this? We weren’t.

U.S. Steel’s Clairton Coke Works is by far the largest emitter of H2S in the county, emitting more than 109 tons in 2017, according to the Pennsylvania Department of Environmental Protection’s eFACTS online data portal. While we were glad to see ACHD put some effort into examining the problem, what we are most interested in is—what’s next?

Evaluation of Hydrogen Sulfide Concentrations at Liberty Borough Monitoring Station-1

Now that ACHD has an answer as to the source of the smelly H2S, what will ACHD and U.S. Steel do to remedy the problem?

In May, Jim Kelly, ACHD Deputy Director for Environmental Health, told the Allegheny County Board of Health that the Air Quality Program planned to revise the county’s coke oven regulations. Board of Health meeting minutes report, “[Jim Kelly] stated that fugitive emissions were responsible for the ‘rotten egg’ smell.

He stated that the rationale for change is that the current H₂S limit in the rule was not protective of the SO₂ NAAQS and that fugitive emissions should be reduced to improve compliance with the H₂S State standard. Elements of the regulation to be changed include the door areas, which will impact allowable visible emissions; coke oven gas, which will impact the allowable H₂S concentration, and updating of equipment lists.”

We know that the Air Quality Program’s Regulation subcommittee is currently reviewing the coke oven regulations. Will revisions to the regulations help to reduce H2S emissions coming from Clairton Coke Works and the rotten egg odor that permeates so much of the Mon Valley and downwind areas? That is yet to be seen, but we will keep you posted. This is a welcome but overdue step in the right direction. Any changes to the County’s air quality regulations must go out for public comment, and we will need your voice when that happens.

–Rachel Filippini, Executive Director

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