Located along the Monongahela River, Clairton, Pennsylvania is a small city in the Pittsburgh metropolitan area with a population of around 6,000 people. Like much of the region, it has a rich history of industrial development, especially steelmaking, that began nearly at its conception.
Opening in 1916, Clairton Coke Works is the largest coke production plant in the United States, producing about 4.3 million tons of coke annually. It is one of the largest polluters in Allegheny County.
The facility employs 1,300 workers in addition to subcontractors through companies like Veolia North America and MPW Industrial Services. The US Steel location is the first destination for raw coal entering the steelmaking process. Coal is baked into coke at temperatures above 2,000 degrees Fahrenheit, producing a more carbon-rich product. From there, some of the coke is transported to the nearby Edgar Thomson Works in Braddock—where it will be used in the blast furnace as fuel to convert iron ore into liquid iron. But most of the coke produced at Clairton is sent out of the region, either to feed the company’s other blast furnaces at the Gary Works in Indiana, or sold into the market for use by other companies.
A History of Unsafe Conditions for Workers and Residents
The Clairton Coke Works has a long history of unsafe working conditions, large incidents, permit violations, and a reputation for cancelling and deferring much-needed upgrades. In September 2009, an explosion occurred due to a gas leak. A maintenance worker, Nick Revetta, was killed and no fines were issued to US Steel. In July 2010, 15 workers were injured in an explosion at one of the facility’s coke ovens. Many of the workers suffered from burn injuries covering between 10% and 40% of their bodies, with some suffering from inhalation-related injuries. Following an investigation, the Occupational Safety and Health Administration (OSHA) penalized US Steel $143,500 for two willful violations for “failure to provide an effective energy control procedure” and 11 serious violations posing risk of harm or death, including:
- Lack of fall protection
- Inadequate lookout/tagout to prevent inadvertent release of energy
- A deficient process safety management program
- Failure to implement an emergency response plan
- Failure to evaluate respiratory hazards
- Failure to use flame retardant gloves
- Failure to use approved electrical equipment
In 2014, a worker was severely burned in the quench tower—the area where the coke is cooled, that raises the water temperature upwards of 150 degrees Fahrenheit. Sixty four-year-old Russell Brown would suffer from second- and third-degree burns before succumbing from his injuries two weeks later. While not much information is available regarding OSHA and US Steel’s investigations into the incident, Brown’s daughter Lisa Marie Coultas would later file a wrongful death lawsuit for failure to provide suitable infrastructure to prevent such an accident—including basic hazard mitigation structures such as guardrails or trench covers.
In the early hours of Christmas Eve 2018, a fire lasting five hours broke out in the Clairton facility’s control room. Many residents weren’t made aware of the fire until about two weeks later. Pollution controls, including the desulfurization equipment, were knocked out for three months, resulting in a 4,500% increase of sulfur in the air paired with a surge in asthma-related cases for months following the incident, a slew of air pollution violations for federal SO2 exceedances, and a crackdown on US Steel’s overall emissions at all of their Mon Valley locations.
In the wake of the fire, US Steel announced in May 2019 that it would invest more than $1 billion in the Mon Valley to reduce pollution and improve efficiency but these plans were dropped by the company two years later.
Ultimately, in 2024, Allegheny County Health Department, PennEnvironment, and Clean Air Council reached a $42 million settlement with US Steel, requiring the company to 1) invest $37 million in control room upgrades including replacement of deteriorating equipment and projects centering the prevention of system outages, 2) pay $5 million to the Allegheny County Department of Health in penalties and to support public health and environmental projects, and 3) allocate $4.5 million to Jefferson Regional Foundation and Allegheny County Department of Economic Development to support heavily impacted communities near US Steel’s Mon Valley plants. US Steel was also ordered to permanently shut down the Clairton plant’s Battery 15.
But the incidents have continued. Even before the deadly explosion in August, the Clairton Coke Works facility had two earlier events in 2025—an explosion that injured two workers in February, and another incident that knocked out pollution controls in June.
The Explosion
On August 11, 2025, US Steel’s Clairton Coke Works was once again the site of a deadly explosion that cost two workers their lives and injured 10 more. The site of the blast was batteries 13 and 14, two series of coke ovens which were originally constructed in the 1920s and had last been upgraded in 1989. The batteries were separated by a “transfer area” which included employee break and personnel rooms. The isolation valve, which allows coke gas to flow into the battery, was going through routine maintenance–in the presence of an Allegheny County Health inspector–at the time of the incident. While US Steel’s procedures authorize the use of low-pressure steam as a method to clean isolation valves, employees were also authorized to use high-pressure water, although not formally stated in maintenance procedures. On the day of the explosion, employees were conducting routine maintenance on batteries 13 and 14 when high-pressure water pumped into the isolation valve began leaking after a “pop” sound and alarms sounding on workers’ gas monitors prompted evacuation orders. Less than a minute later, the batteries exploded, prompting search and rescue operations. Thirty-nine-year-old Timothy Quinn and 52-year-old Steven Menefee were killed.
Chemical Safety Board Funding Cuts
The US Chemical Safety and Hazard Investigation Board in late September issued an update concerning its investigation into August’s deadly blast at Clairton. The board, an independent federal agency responsible for investigating incidents that might, or do, result in the release of hazardous substances, is unable to enforce or create regulations in the way that Occupational Health and Safety (OSHA) or the Environmental Protection Agency (EPA) can, but it does serve a unique purpose as it investigates the root causes of chemical safety incidents, releases reports, and makes safety and hazard recommendations.
As part of its investigation, the CBS said it needed to continue to gather facts and analyze several key areas including: determining the cause and source of the gas release that led to the explosion; metallurgical analysis of the cast iron coke oven gas valves and US Steel’s use of cast iron in coke oven gas piping; and US Steel’s policies, procedures, and safety management systems. However, since President Trump has proposed eliminating funding for the US Chemical Safety and Hazard Investigation Board in the 2026 budget, the future of the investigation is up in the air.
Community Impacts
While US Steel reported a $384 million profit in 2024, the city of Clairton is in the 90th percentile for poverty, nationally, with 29.9% of its residents living below the poverty line compared to 10.6% at the national level. With the city of Clairton at the 93rd national percentile for households with persons with a disability and 88th percentile for population aged 65 years and older, respectively, much of the city is especially vulnerable to such high levels of pollution. According to this National Air Toxics Assessment Report, Allegheny County residents have some of the highest risks of cancer from environmental pollutants. The county is listed at the 99th percentile nationally for environmental factors that pose a risk to human health, including some of the highest rates of vulnerability related to proximity to pollution sources, exposure to pollutants such as black carbon, lead in drinking water, and cancer-causing air pollutants that damage respiratory, neurological, developmental, and reproductive systems. Carcinogens such as coke gas, formaldehyde, and diesel particulate matter released by Clairton Coke Works and other similar facilities have led to some of the highest rates of childhood cancer and asthma in the country. In fact, according to the US Climate Vulnerability Index, Allegheny County has the highest rate of childhood asthma in the state of Pennsylvania, with Clairton having some of the highest rates of air pollution-related deaths in the country due to impacts of ground-level ozone on the respiratory and cardiovascular systems.
This past November, the Allegheny County Council voted to increase fees incurred by the county’s industrial polluters, which will go toward the county’s Air Quality Program. The largest polluters will have annual fees increased sixfold. But at the same time, the Trump administration has reversed course again on a new air pollution rule for coke ovens, granting two-year waivers to coke oven plants for the rule that would have required plants, such as US Steel’s Clairton Plant, to monitor for cancer-causing emissions at the fence line.
New owners, Nippon Steel, have committed to investing nearly $11 billion in US Steel’s facilities, including $2.4 billion of planned capital investment in the facilities that make up the Mon Valley Works, which could lay the groundwork for the US to be competitive in the low-emission steel market. However, Nippon has instead so far signaled a doubling down on coal-based steel production by promising to reline or repair six US Steel blast furnaces by 2030, contradicting its stated goal of going carbon-neutral by 2050. A US Steel executive in November said that capital will be directed to the Clairton Coke Plant; however, details on planned investment have not been made public.
Residents of Clairton and Allegheny County have a right to live, work, and play in a community free from a constant threat of pollution and health risks caused or exacerbated by environmental toxins. Employees have a right to feed themselves and their families while working under safe conditions. Any future industrial investment in Allegheny County should prioritize the health and safety of its workers and residents—rebuilding trust and strengthening communities impacted most by environmental injustice.
Update: On December 23, 2025, the US Chemical Health & Safety Board issued two interim safety recommendations to US Steel in regard to Clairton Coke Works—perform thorough evaluations of all buildings that are, or could be, occupied for potential workplace hazards, and reduce any safety risks identified according to industry safety standards.