The Allegheny County Health Department has found no indication of a long-term health emergency after U.S. Steel’s Clairton Coke Works experienced a breakdown of pollution control equipment this week.
A breakdown occurs when equipment stops working properly and releases more pollution than usual, county health officials said in a statement Thursday. Such equipment failures can be spurred by power outages and other unexpected problems.
According to county officials, Control Room 2 at Clairton Coke Works went offline Tuesday at about 8:05 p.m. and lasted until about 8:30 p.m. the next day.
During the outage, Control Rooms 2 and 5 were not processing coke oven gas.
U.S. Steel in a statement said no one was injured and employees had immediately began the process of restarting the control room.
Both impacted control rooms have returned to normal operations, U.S. Steel said.
“Environmental compliance and safety remain our top priorities,” the company’s statement continued.
County health department monitors recorded elevated readings of hydrogen sulfide (H2S), sulfur dioxide (SO2) and PM2.5, a small particulate matter, at the Liberty monitor site Wednesday morning. The highest readings were reported between 6 a.m. and 9 a.m., when light winds from the southwest and a weak temperature inversion trapped pollutants.
Those readings were not high enough to exceed a one-hour or 24-hour air quality standard, officials said.
Hydrogen sulfide levels were elevated at county monitors in the surrounding areas, officials said.
A colorless gas that is known to smell like rotten eggs, hydrogen sulfide can cause headaches, nausea, dizziness, eye and throat irritation and respiratory discomfort at concentration levels over 2 parts per million, according to the U.S. Department of Labor’s Occupational Safety and Health Administration. The highest hourly concentration recorded during this incident was 0.019 parts per million.
“Currently, ACHD has limited information regarding the cause of the breakdown but has requested more information and has inspectors onsite inspecting coking operations,” county officials said in a news release.
U.S. Steel will be required to submit a report within a week.
County officials said there is “no indication of a long-term health emergency,” but the health department will closely monitor air quality in and around Liberty, Clairton and North Braddock.
Health officials encouraged residents in the area who experienced prolonged, intense symptoms to seek medical care. Hourly updates are posted to an online Air Quality Dashboard, as well as the Hydrogen Sulfide Dashboard.
An explosion at Clairton Coke Works in August left two dead and others hurt. Officials ramped up pollution checks after the incident. U.S. Steel officials said there had been no indications of safety concerns prior to the fatal blast.