5 Things to Know About this Week’s Clairton Coke Works Breakdown

Friends, it’s been a week. Regionally, we’ve dealt with Canadian wildfire smoke impacts, and the Mon Valley has suffered through five straight days of stench and crazy elevated hydrogen sulfide concentrations.

Then on Tuesday came the big news: There was a breakdown at U.S. Steel’s Clairton Coke Works facility Monday evening that knocked out pollution control equipment that removes dangerous chemicals like H2S and ammonia from coke oven gas.

Allegheny County Health Department (ACHD) sent out a news release Tuesday afternoon announcing the incident. You can read more about that here.

But we wanted to flag five things we think you need to know about the incident.

1. The incident took place around 7 p.m. in Control Room 5, which was shut down for repairs through 3:05 a.m. That means that only partially cleaned coke oven gas spewed from the facility for eight hours.

   
   

2. During this incident, there was a “significant” spike in H2S. How significant? Consider this: The highest hourly H2S concentrations measured at ACHD’s Liberty air quality monitor happened at 9 p.m. Monday at 32 ppb (that’s parts per billion). Usually, people can smell H2S (that rotten egg odor) at 5 ppb (which is also the 24-hour average limit in PA). The health department indicated that Allegheny County is “normally below 1 ppb.” 

   
   

3. There were also spiking levels of sulfur dioxide during the breakdown. According to ACHD data, the highest hourly SO2 concentration during the breakdown was 47 ppb at 10 p.m. Monday. As a comparison, SO2 was at just 1 ppb at the same monitoring location at 1 p.m. Tuesday.

   
   

4. Control Room 5 was also one of three at the Clairton Coke Works that experienced an outage during the July 4, 2022, breakdown as well as the high-profile Christmas Eve fire in 2018. Electrical issues were at the root of those breakdowns.

   
   

5. ACHD’s news release indicated that U.S. Steel submitted an initial breakdown report, but did not note whether it was received within the one-hour window required by Clairton Coke Works’ Title V permit. The company has seven days from the date of the incident to submit a follow up report to ACHD.

GASP staff continues to follow these issues closely. We plan to submit a public records request to get further details on what happened, when they happened, and whether or not U.S. Steel followed protocol. Stay tuned.