Explosion sparked by coke oven gas igniting

Multiple agencies will investigate Monday’s Clairton Coke Works tragedy that left two workers dead.

An ordinary shift at U.S. Steel’s Clairton Coke Works was shattered by an explosion Monday morning that claimed two lives, injured several more and sent shockwaves far beyond the plant gates.

By Tuesday, the grief that gripped Clairton was matched by determination — from officials, union leaders and residents — to understand the cause of the accident and make sure it never happens again.

While the grief is still raw, county officials, union leaders and executives stood outside the gates to the plant to speak directly to the community.

“Today is a terribly sad day here in Allegheny County,” said County Executive Sara Innamorato. “Our thoughts and prayers and hearts are with the employees here at U.S. Steel … their family and friends and the entire community of Clairton.”

In Clairton, steel is more than an industry. It’s the soundtrack of the town — the rumble of freight cars, the hiss of steam and the glow of the coke batteries that light up the Monongahela River on cold nights.

That familiar rhythm broke when an explosion tore through batteries 13 and 14.

Waiting for answers

According to U.S. Steel officials, Monday’s blast occurred during what was described as “normal course of business” at batteries 13 and 14 — two adjacent coke oven units where coal is baked at high temperatures to produce coke for steelmaking.

Scott Buckiso, who oversees U.S. Steel’s North American Flat-Rolled operations, said workers were in the process of “charging ovens and pushing coke out of ovens” when the incident happened.

Nearby, other employees were preparing for a maintenance job that had been scheduled for the following week.

The explosion was sparked when coke oven gas — a combustible byproduct of the process — ignited.

Officials confirmed there was “one explosion that involved coke oven gas,” followed by the activation of rupture gates on a separate set of batteries.

Those gates, designed to release excess pressure, caused visible plumes that some witnesses initially mistook for additional blasts.

“There was some back pressure into 19 and 20 battery,” Buckiso explained. “Those rupture gates … did their job. They released. That’s why we saw a bit of a plume when those two occurred. But they did exactly what they were supposed to do from a safety standpoint.”

As the situation unfolded, crews shut off gas flow to the affected area and accounted for all workers.

Batteries 13 and 14 were taken offline immediately and will remain shut down until a comprehensive investigation is completed. The process could take months or even longer.

As a precaution, batteries 19 and 20 — where the rupture valves had activated — were also shut down for repairs.

First responders, fast action

The explosion triggered an allhands response as dozens of local fire companies, paramedics and emergency crews converged on the site.

Innamorato said Allegheny County’s emergency services and police worked “to coordinate response, to work with U.S. Steel and the employees to gather information to determine what happened.”

Air quality — a common source of anxiety in Clairton, where past emissions violations have sparked lawsuits and protests — was closely monitored.

County and state environmental agencies reported that particulate matter, sulfur dioxide and hydrogen sulfide levels stayed within safe limits throughout the day, allowing a temporary stay-at-home order to be lifted Monday evening.

Calls for accountability

U.S. Steel CEO David Burritt addressed the media Tuesday with a mix of sorrow and resolve.

“Safety is and always will be our number one priority every shift, every day, every facility,” he said. “We will share as much as we can, as soon as we can, and we will take every step necessary to keep our people safe.”

Union leaders say those words will be measured against action.

“Every worker deserves to go home every day,” said United Steelworkers District 10 Director Bernie Hall. “The families of those who lost their lives and were injured yesterday deserve nothing less than a full and transparent investigation.”

The investigation into the deadly explosion will involve multiple agencies and could take several months.

OSHA will lead the federal workplace safety probe, inspect equipment and interview workers, while the DEP checks for any environmental violations and reviews emissions data.

The Allegheny County fire marshal will investigate the ignition source and safety compliance, with the United Steelworkers Safety Committee likely conducting its own review to advocate for worker concerns.

An internal team from the company will examine operations, maintenance logs and equipment performance.

“I have assurance from U.S. Steel that they will continue to cooperate fully with our team at Allegheny County to get the information we need to do a thorough investigation,” Innamorato said. “I think we all share a common goal that we want to get to the bottom of what happened and we want to prevent it from ever happening again.”

Burritt said the investigation will be comprehensive and fact based, with information shared as it becomes available.

“We owe it to the families of those we lost, and to every worker here, to make sure nothing like this happens again,” Burritt said. “Every finding from this investigation will be used to strengthen our safety protocols and equipment.

“This process isn’t just about finding answers — it’s about making this facility safer for the long term.”

Legacy of those lost

Gov. Josh Shapiro praised Innamorato for her leadership in managing the emergency, coordinating resources and supporting the community.

He thanked first responders and United Steelworkers members for their daily contributions, noting that their work is dangerous and should never be as perilous as it was during the explosion.

Shapiro said Burritt assured him the company is committed to fully investigating the cause, ensuring worker safety upon reopening and protecting the surrounding community. He emphasized that local, state and federal agencies are working together, but reminded everyone this is foremost a human tragedy that claimed two lives.

One of the lives lost was Timothy Quinn, known affectionately as “TQ.”

A hard worker, Quinn had been employed at the mill since 2008 and had become a mentor and friendly face.

“TQ was a special person, a devoted father of three, someone who I understood served as a mentor to the other steel workers who were here, someone that apparently you would go to on a rough day when you needed a joke or when you needed your stones busted,” Shapiro said. “He was the guy who was there for others while being there as a leader in this plant.”

Quinn cared for his mother, his children and his girlfriend’s children.

“I think it’s important to note that he was also a second-generation steel worker,” Shapiro said. “He followed in his father’s footsteps, and as his sister, Trisha, and his girlfriend, Lucy, shared with me, he was also a mama’s boy who, after working long and tough shifts here at the plant, would go take care of his mom and look after his three children and look after Lucy’s two children as well.

“He was devoted to them. He cared about them, and his life was cut too short because of what happened here at this plant.”

Shapiro vowed to honor Quinn and ensure his children know the man he was.

“We have a responsibility to remember his legacy, to make sure that his memory lives on,” the governor said. “We will honor his legacy, and we will make sure that his children know that their dad was a special man, a good man, and a man who helped build this community with his hands the way his father did.”

While the second victim’s family has asked for privacy, the prayers of neighbors and strangers have filled social media feeds and church bulletins across the Mon Valley.

GoFundMe set up for victim

On Monday, officials reported five of the injured remained in critical but stable condition at hospitals. Five others had been treated and released. They did not provide updates on their conditions Tuesday and could not comment on the extent of their injuries.

One injured worker, Ty Antonelli, has been identified by his family as one of the victims in Monday’s explosion.

A GoFundMe has been established by Daisha Reed to assist him and his family in his recovery.

“As many of you may have heard, there was an explosion at the US Steel Clairton plant. The Antonelli family has been deeply impacted as Ty was one of the victims working during the tragedy,” Reed wrote. “Ty is a devoted husband, and father to (three) beautiful children that has sacrificed a lot to be able to provide for his family. His wife Allesandra gave birth to a healthy baby boy two months ago, and currently is in nursing school to chase her dreams.

“Allesandra and Ty are college sweethearts, and they are truly each other’s best friend. They have always been the couple that you could call with any problem, and they would do their best to find a positive solution. For this tragedy that occurred, we want to be THEIR positive solution. We’re asking for your help during this difficult time. Your generosity will go directly toward Ty’s recovery, living expensive, and the essentials he’ll need while he heals. Our hearts go out to all the families that have been severely impacted during this difficult time. From the bottom of our hearts, we thank you for your kindness and prayers.”

The page can be found by going to GoFundMe and searching for “US Steel Clairton Explosion.” More than $11,000 of an $18,000 goal had been raised Tuesday night.

In addition to the employees, two medics were also taken to an area hospital for evaluation.

The future of steel in the Mon Valley

As investigators begin their work — a process with no set timeline — attention is turning to what comes next.

U.S. Steel, in the process of being acquired by Japan’s Nippon Steel, has committed more than $2 billion in upgrades to the Mon Valley Works.

Burritt said those investments will make the facility “safer and more efficient,” adding that Monday’s tragedy will not have an impact on the future of the mill in the Mon Valley.

“These investments from Nippon Steel are not just about modernizing equipment — they’re about making this a safer place to work,” Burritt said. “Nippon understands that our people are our most important asset, and their commitment will help us reduce risks and protect every worker who steps through these gates.

“… Safety is at the core of this partnership, and the upgrades we’ll be able to make with Nippon’s support will strengthen our operations for the long term.”

Shapiro, who has supported the Nippon deal, said the upgrades must do more than modernize equipment.

“We can make sure that the neighbors who live in the area have confidence in the air they breathe and the water they drink, that the workers … have confidence in the safety of this facility,” Shapiro said.

For now, the affected coke batteries remain offline.

Counseling services are in place for employees, and families of the victims are being offered ongoing support.

Clairton is no stranger to tragedy, but its people are also no strangers to resilience.

In church halls and union meeting rooms, in quiet kitchen conversations and at the plant gates, the same question is being asked: How do we prevent any more catastrophic accidents in the future?

As Shapiro put it, “This is more than a plant. It’s part of the fabric of this community. We owe it to the people here to make sure this never happens again.”