Statement from ACHD on US Steel’s Clairton Coke Works Breakdown
Published on June 03, 2025
Statement from ACHD on US Steel’s Clairton Coke Works Breakdown
PITTSBURGH – Last evening there was an issue at the Clairton Coke Works in Clairton, according to breakdown reports submitted to the Allegheny County Health Department (ACHD) by US Steel.
The reports indicate there was elevated sulfur levels in coke oven gas while repairs took place within a control room. The incident occurred on June 2nd at 7:08 pm and it was reported that all equipment was back online on June 3rd at 3:05 am.
The preliminary report says during the breakdown, control room five was shut down and bypassed meaning that Coke oven gas was only partially treated by control rooms one and two. As a result, the gas produced during coke-making - called coke oven gas - was only partly cleaned by the remaining control systems. Control room five removes harmful chemicals like hydrogen sulfide and ammonia from the gas. U.S. Steel has seven days to submit a full report explaining what happened.
During the breakdown a significant spike of hydrogen sulfide and sulfur dioxide were measured at the ACHD Liberty Monitor. The highest hourly H2S concentration measured at the ACHD Liberty Monitor occurred on June 2nd at 9:00 PM at 32 ppb. For H2S, the ability to smell it and the state regulatory level is 5 ppb. Allegheny County is normally below 1 ppb, see Hydrogen Sulfide - Allegheny County, PA. The highest hourly sulfur dioxide (SO2) concentration during the breakdown was 47 ppb on June 2nd at 10:00 pm. As a comparison, SO2 was at 1 ppb at the same location at 1:00 pm today.
The Allegheny County Health Department is at Clairton for a pre-planned stack test today and is gathering additional information on the breakdown as well.
For more information regarding issues within the Clairton Coke Works facility reach out to US Steel.
The Allegheny County Health Department (ACHD) will continue to investigate the breakdown.
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The Allegheny County Health Department's mission is to protect, promote, and preserve the health and well-being of the more than 1.2 million people who call Allegheny County home.
Media inquiries may be directed to Ronnie Das,
Public Information Officer for the Health Department,
at ronnie.das@alleghenycounty.us or by phone at 412-578-7991.