The Allegheny County Health Department says there was an “incident” early Wednesday morning at the Clairton Coke Works that left two people injured and caused a large boom.
The department says US Steel informed them of an issue with “its B Battery”.
A hydraulic failure of a switch in the battery led to “buildup of combustible material in the under-fire system, which then ignited.”
That caused the loud sound some in the area may have heard.
It also caused emissions to leak for about 20 seconds.
The ACHD says that the battery was not damaged in the incident but was put on idle until US Steel can investigate.
US Steel also says two people were injured, “getting material” in their eyes. They were taken to the hospital with non-serious injuries.
“While there was an uptick in readings at the Clairton monitor around 4:45 am this morning lasting approximately 75 minutes, the pollutions rates rose from 3.5 to 8 μg/m which is well under the EPA 24-hour rate of 35 μg/m.,” ACHD said in a statement.
Monitoring will continue.