The coke is used in what’s known as “integrated” steelmaking. Coke is combined with iron ore and limestone in a scorching-hot blast furnace to produce iron. The molten metal is then moved into a basic oxygen furnace where it becomes steel — the essential and abundant material used in bridges, buildings, ships, cars, and household appliances.
The number of U.S. coal-based steelmaking facilities has declined over the decades, owing largely to growing competition overseas and shifting market conditions at home. No new steel facilities that use coal have been built in the U.S. in decades. Today, roughly 30% of the country’s steel production is made the traditional way.
The remaining 70% of domestic steel output comes from electric arc furnaces, many of which are scattered across the U.S. South. These giant facilities use electricity to melt scrap metal — a method that can significantly curb CO2 emissions and reduce air pollution compared to using coal, especially if that electricity is being generated with clean energy.
But recycled steel can’t entirely displace demand for high-strength “primary” steel. In order to truly clean up steelmaking, the industry must end its reliance on coal, experts say.
“We know that there are alternatives that don’t involve coke-making,” Hilary Lewis, steel director at Industrious Labs, said days after the Clairton explosion. “And if we have ways to do this that are safer for workers, safer for communities, we should be seriously considering them.”
Today, the leading alternative for coke-fed blast furnaces is the “direct reduced iron” process, or DRI. Existing DRI plants typically use fossil gas to convert iron ore into iron, which is relatively cleaner than using coal. But if producers swapped gas for green hydrogen — made with renewable power — they could slash the overall CO2 emissions from steelmaking by up to 90%.
The iron can then be melted into steel in an electric arc furnace, ideally one that’s also powered by carbon-free electricity, though that’s not typically the case today.
Green steel’s path is still uncertain in U.S.
For now, this fossil-fuel-free arrangement mostly remains out of reach, given the challenging economics and the persistent lack of green hydrogen supplies globally.
A handful of commercial-scale projects are slowly advancing in Europe and China. But plans to build two hydrogen-based steel mills in the United States have recently been abandoned.
Last year, the steelmakers SSAB and Cleveland-Cliffs were selected to receive up to $500 million each from the Biden-era Department of Energy to build green steel facilities in Mississippi and Ohio, respectively. In January, SSAB told Canary Media it had withdrawn from federal award negotiations. In July, Cleveland-Cliffs said it informed the DOE — now under President Donald Trump — that the company was no longer pursuing its project, citing the lack of hydrogen and its intention to keep using “beautiful coal, beautiful coke, beautiful natural gas.”
The Trump administration is encouraging the U.S. steel industry to double down on coal. In May, Energy Secretary Chris Wright designated metallurgical coal as a “critical material” for the U.S. supply chain. The GOP megalaw passed last month allows coal producers to claim the advanced manufacturing tax credit through 2029, helping to reduce the cost of coal-based steelmaking, both domestically and in countries that import U.S. metallurgical coal.
Most notably for Clairton Coke Works, the Environmental Protection Agency recently moved to delay requiring coking plants to comply with new air-quality standards until July 2027. The rules set caps on previously unregulated air pollutants. They also required plants to monitor pollution — a measure that can provide key data about a community’s exposure risk following major accidents.
In the wake of the fatal explosion at Clairton, the Allegheny County Health Department said it was increasing air-quality monitoring near the facility to assess for pollutants such as volatile organic compounds, fine particulate matter, and sulfur dioxide. Initial reports suggest the weather helped to lessen the potential pollution impact from the blast by dispersing plumes, rather than trapping them in place.
For Ansari, of Valley Clean Air Now, the last few days have been a hectic blur. His group has managed to donate hundreds of air purifiers across the Mon Valley, and he’s been encouraging residents to have their blood drawn to document any potential chemical exposure from the blast.
“The community has definitely responded and rallied around us, and I’m very grateful for that,” he said. “But it’s unfortunate, because I feel like all of this could have been avoided.”
