Tragedy at Clairton Plant Renews Old Worries

Following explosion that killed 2, groups wonder about safety at coke works

By Staff Reports
The Tube City Almanac
August 14, 2025
Posted in: State & Region

This story was written by Tube City Almanac Editor Jason Togyer and includes reporting by Danielle Smith of Keystone State News Connection.

A massive explosion at U.S. Steel’s Clairton Plant killed two workers and injured an unknown number of other employees. A camera operated by the non-profit Breathe Project captured the moment of the blast. The investigation into the cause of the explosion “is going to take time,” Allegheny County Executive Sara Innamorato said. (Keystone State News Connection photo courtesy Breathe Project) 

As local and federal authorities investigate a deadly blast at U.S. Steel’s Clairton Plant, local groups have renewed their concerns about the health and safety of plant workers and the community.

Two employees died and at least 12 people were treated at local hospitals following an explosion Monday morning at the facilty, which employs about 1,400 workers.

Clairton Plant is the largest operation of its kind in North America. It superheats coal in giant ovens, called batteries, to produce coke, a fuel used in blast furnaces for steelmaking.

The Allegheny County medical examiner’s office identified one of the victims as Timothy Quinn, 39, of Westmoreland County. He was pronounced dead at the scene. The name of the other victim has not yet officially been released.

Emergency personnel said two workers were treated at the scene and an unknown number of employees were treated at the Clairton Plant hospital.

Investigators are still working to determine the total number of injuries from the blast, a county spokeswoman said.

In total, 14 local fire departments and 20 ambulance and rescue services responded to the scene to assist, Allegheny County officials said. Two medics were taken to an area hospital for evaluation.

The blast is being investigated by Allegheny County police, the Allegheny County fire marshal’s office, and other state and local agencies.

Interviews have also started with some of the workers who were on site at the time of the explosion, a county spokeswoman said.

Innamorato: ‘Investigation is going to take time’

“We understand this is a high-profile incident, but we want to stress this investigation is going to take time,” Allegheny County Executive Sara Innamorato said. “The families of workers killed, those who were injured, and the community deserve a thorough investigation to determine exactly what happened.”

The U.S. Chemical Safety & Hazard Investigation Board is also sending a team to investigate.

Pennsylvania Gov. Josh Shapiro visited the area on Tuesday to offer condolences and praise emergency responders and government officials. He said U.S. Steel is committed to finding the cause and ensuring safety.

The company’s chief executive officer, David B. Burritt, has also pledged to cooperate with authorities.

“U.S. Steel has pledged full cooperation and transparency, and we will hold them to that standard as we move forward with the investigation,” Innamorato said.

Matthew Mehalik, executive director of the Breathe Project in Pittsburgh, said his group’s cameras point directly at the plant and captured the explosion. But their sensor network did not detect high pollution levels, because he said the hot gas plume was carried northeast by the wind, dispersing before reaching the city.

A spokeswoman for the Allegheny County Health Department said that air-quality monitoring stations in Clairton, Liberty and North Braddock all showed levels of particulate matter — tiny soot particles called PM 2.5 — and sulfur dioxide to be within national air quality standards throughout Monday.

Hydrogen sulfide levels were also low and below the state’s nuisance threshold level, the county said.

Two health department staff members were at Clairton Plant Monday for routine inspections and were present during the explosion, the county said. One sustained injuries, was hospitalized and since has been released.

The health department said it continues to monitor the situation and had contractors on site today performing routine inspections of the coking operations.

Environmental groups: Long history of fines, penalties

Mehalik emphasized the need for continued monitoring and worker safety.

“The plant hasn’t been totally shut down, to our understanding,” Mehalik said. “There are some concerns about ongoing operating of the plant, safety of the community in general and especially safety for workers, and whether or not the explosion damaged enough of this plant that makes it risky to operate other parts of it.”

Mehalik noted the Clairton Plant and other parts of U.S. Steel’s Mon Valley Works have faced more than $64 million in fines in the past five years, including more than $7 million this year for air permit violations.

“They like to talk a good game about worker safety and the environment but their actions in the documented evidence of past fines suggest they minimize what they need to do to operate this plant,” Mehalik said.

U.S. Steel is now a subsidiary of Japan-based Nippon Steel Corp., which acquired the company in a nearly $15 billion deal.

Nippon Steel has promised to commit roughly $2.2 billion to modernize Clairton Plant and other facilities, including Irvin Plant in West Mifflin and Edgar Thomson Plant in Braddock and North Braddock.

David Masur, executive director of PennEnvironment, said his group has advocated for many years for U.S. Steel to address pollution and safety at Clairton and other Mon Valley plants.

It is now calling for a full and independent investigation, as well as a safety review of the infrastructure at the Clairton Plant, which has operated for almost 125 years.

PennEnvironment released a statement recalling a 2019 lawsuit against U.S. Steel for Clean Air Act violations. Masur noted the case was settled last year for $42 million and includes pollution controls, shutting down one coke battery and making plant upgrades.

“Whomever owns it, the standard we should be setting, either at the county or state level, or federally, is they should be using all the tools available to make sure that they're reducing their pollution and their emissions and protecting public health and as we sadly saw in this case, protecting their workers,” Masur said.

Federal investigator: Accident ‘could have been prevented’

One board member for the U.S. Chemical Safety & Hazard Investigation Board was blunt. CSB Board Member Sylvia Johnson said the incident “should not have happened and potentially could have been prevented.”

Steve Owens, who chairs the chemical safety board, said the agency will partner with other investigators to find out what went wrong.

“The CSB will work to determine the cause of this tragic incident and identify actions that can be taken to help ensure that a similar disaster like this does not happen again,” Owens said.

The CSB is an independent federal agency charged with investigating incidents and hazards that result, or may result, in the catastrophic release of extremely hazardous substances.

The agency does not issue citations or fines but makes safety recommendations to companies, industry organizations, labor groups, and regulatory agencies such as the U.S. Occupational Safety & Health Administration and Environmental Protection Agency.

Jason Togyer is editor of Tube City Almanac and volunteer executive director of Tube City Community Media Inc. Danielle M. Smith is a producer for Public News Service, where this story first appeared. An award-winning radio journalist/personality with more than a decade of experience in broadcast media, she is a former audio journalist with American Urban Radio Networks and Sheridan Broadcasting Networks who also hosts a weekly community affairs show “Good News” on WGBN (1360 AM/98.9 FM).

Originally published August 14, 2025.

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