01/29/2026
Statement from ACHD on US Steel’s Clairton Coke Works Breakdown
The Allegheny County Health Department (ACHD) received a call from U.S. Steel regarding a breakdown of pollution control equipment at Clairton Coke Works. A breakdown happens when equipment isn’t working properly and releases more pollution than normal. This can happen when equipment fails, during power outages, or other unexpected problems happen.
Our initial understanding is that Control Room 2 went offline due to a breakdown beginning on January 27 at approximately 8:05 pm. As a result, Control Rooms 2 and 5 were not processing coke oven gas and the partially processed coke oven gas was combusted at the facility. The outage lasted until January 28 at approximately 8:20 pm. At this time, equipment is back online.
ACHD monitors recorded elevated readings of H2S, SO2, and PM2.5 at the Liberty monitor site on the morning of January 28. The highest readings were between 6 and 9 am when there were light winds from the southwest and a weak temperature inversion which can trap pollutants to the surface. The elevated readings were not high enough to cause a 1-hour or 24-hour exceedance of any air quality standard.
During this event, Hydrogen Sulfide (H2S) levels elevated at ACHD monitors in the surrounding areas. H2S is a colorless gas with a strong “rotten egg” odor. According to the U.S. Department of Labor’s Occupational Safety and Health Administration (OSHA), short-term exposure at high concentration levels (over 2 ppm) can cause symptoms such as headaches, nausea, dizziness, eye or throat irritation, and respiratory discomfort, particularly for individuals with asthma or other underlying lung conditions. The highest hourly concentration recorded was 0.019 ppm.
Currently, ACHD has limited information regarding the cause of the breakdown but has requested more information and has inspectors onsite inspecting coking operations. U.S. Steel is required to submit a breakdown report within seven days. There is also an additional 30-day reporting requirement.
Currently there is no indication of a long-term health emergency; however, ACHD will continue to closely monitor air quality in and around Liberty, Clairton, and North Braddock. Residents in the affected area who experience prolonged and intense symptoms are encouraged to seek medical care. The public is also encouraged to use the Air Quality Dashboard and the Hydrogen Sulfide Dashboard for hourly updates.
For more information regarding issues within the Clairton Coke Works facility, reach out to US Steel.
The Allegheny County Health Department will continue to investigate the breakdown and provide information to the public as it becomes available.
The Health Department takes are quality incidents seriously and is committed to protecting public health through ongoing monitoring, enforcement of air quality regulations, and transparent communication with the community.
