This article was updated to reflect findings from the US Chemical Safety and Hazard Investigation Board’s final report on the fatal explosion at the U.S. Steel Clairton Coke Works facility.
August 11 marked one year since an explosion at the Mon Valley Works’ Clairton Coke Plant took the life of two steelworkers and injured ten more.
The blast, which occurred while maintenance was being performed on batteries 13 and 14, and resulted in a temporary shelter-in-place order for nearby residents, came just shy of two months after U.S. Steel was acquired by Japan’s Nippon Steel.
And despite the deal including a national security agreement with the federal government that requires Nippon to spend $2.4 billion on the Mon Valley Works – and invest $10.8 billion across U.S. Steel’s operations – so far no major upgrades have been announced for the Clairton facility.
Following the incident, U.S. Steel placed the #13 and #14 coke batteries on a hot idle, or temporary production suspension, as repairs were made to the facility. Production resumed at the #14 coke battery in October 2025 and the #13 battery in February 2026.
The US Chemical Safety and Hazard Investigation Board (CSB), an independent federal agency responsible for investigating industrial incidents, spent a year looking into what went wrong that day in Clairton. In a final report issued on August 10, the CSB said the deadly incident, which also caused an estimated $52.5 million in property damage, was the result of an ad hoc informal procedure, poor facility siting, and an ineffective process safety management system at Clairton and “should never have happened.”
A pair of wrongful death lawsuits filed by the families of the two workers killed last August allege the company was warned about the dangerous configuration at the plant for decades. In 2003, a facility siting study was recommended to see if occupied buildings were too close to explosion hazards, but management rejected the recommendation, claiming their system was exempt from certain OSHA regulations.
Beyond the fixes to get Clairton back up and running, U.S. Steel and its parent company Nippon have not announced any major investment at the site. According to materials provided at a recent open house event hosted by the company, U.S. Steel says it spends about $100 million annually for environmental improvements and compliance in the Mon Valley.
Meanwhile, in a recent update regarding ongoing contract negotiations with U.S. Steel sent before the release of the CSB’s final report, the United Steelworkers said it is fighting for several “common-sense improvements, including better siting practices, structural inspections, additional training, improved equipment for emergency responders, more robust training for electricians to enable them to do their jobs, and mental health resources for workers impacted when a fatal catastrophe occurs.”
The Mon Valley’s workers and communities deserve real investment in safer, modern operations. Not a band-aid to continue business as usual.
Nippon’s greener steel investments land in Arkansas
With nearly $11 billion to spend, Nippon could dramatically shift the way steel is made in the US.
And it is. In late April, it was announced Nippon would invest $1.9 billion to build a new, first-of-its-kind direct reduced iron (DRI) facility in the US, which has the potential to produce steel with near-zero emissions when paired with renewable energy and green hydrogen.
The problem for the Mon Valley is, this investment isn’t happening here.
Instead, next-generation, lower-emissions steel will be made in Arkansas, and it will be made with a non-union workforce.
Nippon’s Mon Valley investments double down on traditional steelmaking
In early June, U.S. Steel grabbed headlines announcing a “new era” of steelmaking in the Mon Valley. But so far, Nippon’s announced investment plans are centered around the construction of a new hot strip mill and slag recycler at the company’s Edgar Thomson facility in Braddock.
The new hot strip mill, which U.S. Steel says will reduce energy consumption, enhance product quality, and expand the Mon Valley’s abilities in automotive and other high-value markets, is overdue and will replace the 87-year-old hot strip mill at Irvin. But from what has been announced, this project seems to do nothing to change the emissions-intensive way they actually make iron and steel in the Mon Valley. It just changes the way they roll it.
It’s unclear how much of the $2.4 billion in planned Mon Valley spending will go to the hot strip mill project. And according to Nippon’s latest quarterly earnings presentation released Aug. 4, the hot strip mill project is not finalized and still needs shareholder approval.
To date, Nippon’s shareholders have only approved $90 million in Mon Valley spending for the new slag recycler at Edgar Thomson, leaving at least $2.31 billion remaining. Overall, of Nippon’s total $10.8 billion in planned US investment under the national security agreement, only about $3.7 billion has been finalized and approved by shareholders, according to the Aug. 4 investor presentation.
A big question now is will the Mon Valley see any substantial investment to modernize its upstream production or does $2.4 billion only buy a hot strip mill and a slag recycler? For those waiting for more, now is the time to ask: is this it?
Greenfield EAF to bring more investment…somewhere
A new hot strip mill, and one that should be built with the most advanced environmental technologies available, should just be the start to modernizing Mon Valley steelmaking, particularly as Nippon says it is scouting states to build a major new electric arc furnace (EAF) steel plant in the US.
Announcing the expansion plans in December 2025, Nippon Steel Vice Chairman Takahiro Mori said the company is envisioning “something like Big River 2,” referring to U.S. Steel’s newest 3 million ton per year EAF operation in Osceola, Arkansas. By comparison, the Mon Valley’s Edgar Thomson Works has an annual raw steel production capability of 2.9 million tons.
Big River, which U.S. Steel fully acquired at the start of 2021, has grown from producing 1.5 million tons of steel annually roughly a decade ago to an annual production capacity of 6 million tons today. In contrast to U.S. Steel’s century-plus-old, coal-based blast furnace operations in the Mon Valley, Big River was the first LEED-certified steel production mill in the US. And, as mentioned earlier, Big River is about to get even more competitive with a new, state-of-the-art DRI facility.
DRI, or direct reduction of iron, replaces the emissions-heavy blast furnace step of the ironmaking process, which traditionally uses coal to reduce iron. And when green hydrogen is used in DRI production, it can provide a virtually emissions-free way to produce primary steel. As more companies respond to the global trend of modernizing and decarbonizing steelmaking, DRI-EAF is being used more both in the US and globally.
Traditional blast furnace-based steelmaking like they do in the Mon Valley, meanwhile, has been on the decline for decades. Even after the crash of Pittsburgh’s steel industry in the 1980s, employment in primary iron and steel manufacturing continued to decline in the Pittsburgh MSA by about 55%, from roughly 12,200 workers in January 1990 to 5,400 workers in 2025, according to Bureau of Labor Statistics data.
But a shift to clean steel production in the Mon Valley can reverse this trend by making the region a competitive hub for next-generation sustainable steel — creating good jobs while cleaning up the air.
A 2023 report by the Ohio River Valley Institute found that a conversion from traditional coal-based processes to steelmaking powered by green hydrogen could be an economic driver for the Mon Valley through retaining steel jobs, creating new renewable energy jobs, and giving the state a first-mover advantage in global markets. However, if investments into cleaner, modern iron and steelmaking don’t happen in historic steel regions like the Mon Valley, these communities and the workers at these facilities are at risk of falling further behind.
Transitioning to clean steelmaking may provide the single best opportunity for US steel companies and steel communities to reverse several decades of eroding steel jobs, wages, and market share. Western Pennsylvania should be on Nippon’s shortlist for a new mill as our region’s workforce, supply chains, and resources make it uniquely positioned to be a leader in modern, sustainable steelmaking.
While Nippon’s national security agreement with the US government also prevents the company from closing, idling, or selling U.S. Steel facilities before June 18, 2035, RMI estimates the next blast furnace relining at Edgar Thomson will need to occur around 2034, meaning the time to transition is now. A transition to green steel production is capital-intensive, but so is continuing the status quo, as blast furnace relining costs run up to an estimated $400 million per unit on a 15- to 25-year cycle. This means how money is spent today will determine what our environment, jobs and tax base will look like for decades to come.
Forging a new future
The investments announced for the Mon Valley so far are significant and overdue. But a new hot strip mill falls short of a forward-looking steelmaking strategy.
The central question facing the Mon Valley is not whether or not Nippon will spend money here. It’s whether those dollars will help transform how steel is made here.
Across the industry, companies are investing in DRI and EAF technologies designed to produce steel with lower emissions, lower costs, and greater competitiveness. The Mon Valley should be receiving those same investments. With our skilled workforce, industrial supply chains, and generations of steelmaking expertise, Western Pennsylvania is uniquely positioned to be a leader in the next generation of steel production.
The once-in-a-generation opportunity in front of us is bigger than preserving existing operations for a few more years. We could create a pathway for the industry to grow and thrive here for decades to come.
For generations, the Mon Valley has helped build America’s prosperity. But for too long, the benefits have flowed elsewhere while local communities were left with polluted air, declining populations, and economic uncertainty. As investments are made, the people who have lived and worked along this industry deserve more than another round of promises. They deserve investments that create good jobs, cleaner air, stronger communities, and a better quality of life.