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GASP Smoke Reader Dispatch: More Concerning Mon Valley Works Emissions Reported to ACHD

Updated: Dec 14, 2022


GASP’s resident smoke reader - longtime project manager Sue Seppi - was back at it again last week, with stops in Clairton and Braddock to observe emissions emanating from U.S. Steel’s Clairton Coke Works and Edgar Thompson facilities.

For those who might not be familiar: smoke readers are volunteers who are trained and certified to recognize and understand:

  • visible emissions from smokestacks

  • what opacity violations look like

  • and how to file reports with the Allegheny County Health Department

During her observations, Sue noted concerning brownish plumes and a rotten-egg odor in Clairton and reported it to the Allegheny County Health Department, our local air quality regulator. She also reported high-opacity smoke from the Edgar Thomson facility.

Here’s the report she sent in:





Seeing frequent similar brownish plumes or sometimes parts of plumes (due to wind keeping plume flow flattish and sometimes behind buildings at Clairton Coke) as seen on previous visits in the same general area.


On Dec. 9, 2022, opacities of plume or partial plume were frequently 20% or higher during a 20-minute period starting at 12:28 pm. I can't see the source. Are these plumes or plume permitted? On this visit, the plume/s in this area were not as long-lasting as previously.


At Edgar Thomson, I observed some heavier opacity plumes on two different dates (see photos) from the same general area-not sure of the source. Are these plumes permitted?


At Clairton, there was a persistent rotten egg odor (Maple Ave.) not at Edgar Thomson (from the opposite side of Allegheny River from ET). Thank you for the opportunity to send comments that may be of assistance to you and healthy air quality.

Editor’s Note: Stay tuned, we’ll keep you posted on ACHD’s response. Last month, the department said it was investigating brown plumes Sue reported. You can learn more about that report here.


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