The Residents' Guide to What U.S. Steel’s Proposed Hot Strip Mill Means for Our Air

If you’ve been following Mon Valley news lately, you’ve probably seen a LOT of headlines around U.S. Steel’s proposed multi-billion-dollar capital investment plan for its local facilities - and at the heart of this plan is a proposal to build a hot strip mill at the Edgar Thomson Works in Braddock.

U.S. Steel has bragged in press releases about efficiency, securing thousands of union jobs, and bringing a historic 150-year-old mill into the modern era. But around here at GASP, we know that when it comes to industrial air pollution, you always have to look past the headlines and dig into the actual data.

Let's break down what a hot strip mill is, what U.S. Steel is promising, why the environmental math isn't quite adding up for the health of the Mon Valley, and how YOU can get involved in the process.

A Little Info on the Current Mon Valley Works Setup

Before we get too deep in the weeds about permits and pollution, let's look at how the Mon Valley Works operates as a team. Right now, the process is split up across a few locations:

• The Clairton Plant bakes coal into coke.

• The Edgar Thomson Plant uses that coke in its blast furnaces to melt down iron ore into liquid iron, which is cast into heavy steel slabs.

• The Irvin Plant in West Mifflin takes those cold steel slabs and heats them back up to extreme temperatures so a machine—a hot strip mill—can roll them flat into massive coils for cars and appliances.

The new plan shifts that last piece of the puzzle - U.S. Steel wants to build a brand-new hot strip mill right at Edgar Thomson, which means they can process the steel slabs right where they are made, possibly decommissioning the 87-year-old mill currently running over at the Irvin Plant.

What is a Hot Strip Mill, Anyway?

The short answer is it’s a massive industrial facility designed to transform thick, semi-finished steel slabs into thin, long strips or coils at extremely high temperatures.

Here’s the process:

1. Reheating: Slabs are heated in a furnace to approximately 1,250°C to ensure they are soft enough to deform without cracking.

2. Descaling: High-pressure water sprays remove mill oxidized layers from the surface to prevent surface defects in the final product.

3. Roughing Mill: Massive rollers reduce the initial slab thickness by about 80 percent through several passes.

4. Finishing Mill: A series tandem stands further compress the steel to its final precise thickness and width.

5. Cooling and Coiling: The strip is rapidly cooled using water before being wound into giant coils weighing up to 35 tons.

The Corporate Argument: More Efficient, Lower Emissions Per Ton

U.S. Steel argues the shift in operations from the Irving Works to Edgar Thomson is a win for the environment, and that moving the new hot strip mill will utilize what’s known in the air quality permitting world as Best Available Control Technologies (or BACT) to keep emissions down.

The company projects that emissions directly associated with the strip mill's operations will drop from 25.4 tons per year (at the old Irvin plant) to about 22 tons per year at the planned Edgar Thomson setup.

U.S. Steel argues that because the mill would be brand new and more efficient, the pollution per ton of steel produced goes down.

The Reality Check: Why Air Quality Advocates are Concerned

While a minor drop in emissions from hot strip mill operations sound good enough on paper, environmental watchdogs and data tell a much more complicated story.

A couple things to keep in mind as this process unfolds:

1. The New Hot Strip Mill Locks in Dirty Coal Technology for Decades

The biggest red flag isn't necessarily what the new mill does as much as what it's going to keep alive: As part of this merger and investment package, Nippon Steel pledged to keep Edgar Thomson's traditional, coal-fired blast furnaces running at full capacity for at least the next 10 years.

While other modern steelmakers are transitioning to Electric Arc Furnaces (EAFs) that melt recycled scrap metal using electricity and emit a fraction of the pollution, U.S. Steel’s hot strip mill project doubles down on traditional blast furnaces.

This means the Mon Valley will continue relying heavily on coal and coke, locking in legacy pollution for years to come.

2. The Facility Will Have a Massive Carbon Footprint

According to EPA estimates, adding a hot strip mill operation directly to the Edgar Thomson facility could increase the plant's greenhouse gas emissions by up to 750,000 tons of carbon per year.

To put that into perspective: Adding 750,000 tons of carbon dioxide to our local ambient air annually is the environmental equivalent of putting 150,000 more cars on the road. It’s also enough carbon dioxide to power 30 homes for an entire year.

But that’s not all: According to a recent analysis from our friends at Carnegie Mellon University’s CREATE Lab, the closure of the Irvin Works facility coupled with emissions impacts from the new hot strip mill at Edgar Thomson would actually expand the Mon Valley Works’ pollution zone substantially.

3. Ongoing Fine Particulate Matter (PM2.5) Concerns

The Mon Valley has a long, well-documented history of air quality struggles. Monitor data consistently show the highest levels of fine particulate matter (PM2.5)—the microscopic soot that penetrates deep into human lungs—are recorded near the Clairton Coke Works and Edgar Thomson facilities.

Mon Valley airshed has historically failed to meet federal clean air standards.

Meanwhile, U.S. Steel’s Mon Valley Works operations have been subject to consent decrees with local and federal officials triggered by ongoing air quality violations at both the Clairton Coke Works and Edgar Thomson.

While U.S. Steel continues to brag about what amounts to minor efficiency gains with the host strip mill, residents and advocates like GASP are concerned that adding even more heavy industrial pollution to a site already struggling to meet basic health-based air standards is a massive gamble for the communities of Braddock, North Braddock, and surrounding municipalities.

The facility itself will be nestled in a cluster of Environmental Justice Communities:

In fact, a recent analysis from CREATE Lab shows the installation of the new hot strip mill wouldn’t lessen pollution as much as shift it: The primary pollution impacts would move to a more densely populated and already burdened population.

What Happens Next?

U.S. Steel wants to move quickly, targeting a production startup in the second half of 2029. However, the company cannot proceed without an approved Title V operating permit (more on this later) from ACHD, which is expected to be published sometime this summer.

Right now, the company is also seeking approvals from local municipal officials and other stakeholders related to issues like zoning and wastewater.

And this is where we collectively come in.

As the permitting process moves forward, there will be windows for public comment when it comes to air quality controls and compliance testing at the facility. That’s because Edgar Thomson is a Title V facility, which comes with a host of regulations and responsibilities.

What You Need to Know About Title V Facilities

Title V of the Clean Air Act requires Major Sources of air pollution to obtain operating permits from the Environmental Protection Agency (EPA) or a state or local agency that EPA has authorized to issue these permits. Major Sources in Allegheny County, like the Edgar Thomson facility, are permitted by the ACHD.

A Major Source is defined as one that has the potential to emit

• at least 100 tons per year of any air pollutant

• 10 tons per year of any single hazardous air pollutant

• or 25 tons per year of any combination of hazardous air pollutants

A Title V Operating Permit is a long, technical document that includes all emissions limits and standards to which a source is subject, as well as all operating, monitoring and reporting requirements that apply at the time of a permit’s issuance.

For folks who want to take a deeper dive into all things Title V permits are invited to check out our online clearinghouse here.

By including all requirements in one document, these permits - in theory - help source operators like U.S. Steel comply with those regulations. But they also help regulators and members of the public enforce them – all with the ultimate goal of reducing air pollution.

A major source of air pollution must apply for a Title V Operating Permit in order to begin normal operations. That Title V Operating Permit is valid for five years, and sources must apply to renew their Title V Operating Permits before their old permits expire.

Once the permit is published, it will go through a mandatory 30-day (or longer) period of time for members of the public to weigh in on the proposal.

ACHD has already approved the company’s installation permit for the facility, which was one of the first air quality-related hurdles. You can read more on that in this story by Jack Troy of the Pittsburgh Tribune Review.

How - and Why - You Should Get Involved

With critical regulatory milestones on the horizon, local residents have a powerful opportunity to demand stronger environmental and public health protections.

Here is how you can get involved and make your voice heard:

Show Up at Local Municipal Meetings

Decisions that impact local zoning, municipal oversight, and community development happen right in your neighborhood council chambers. Local leaders need to know that air quality and industrial oversight are top priorities for constituents like you.

Attending city and borough council meetings is one of the best ways to stay informed about what decisions community leaders are making regarding local facilities.

If you live in North Braddock or Braddock, you can reach out directly to your municipal officials to voice your concerns or ask about upcoming agenda items related to Edgar Thomson:

North Braddock Borough Officials

●     Mayor: Cletus Lee – toddle.cl@gmail.com

●     Borough Manager: Cory Ruff – northbraddock.mgr@gmail.com

●     Council President: Lisa Franklin-Robinson - admin@northbraddockborough.com

Braddock Borough Officials

●     Mayor: Delia Lennon-Winstead - mayor@braddockborough.com

●     Borough Manager: Lou Ransom Jr. - manager@braddockborough.com

●     Council President: LuJuan Reeves - councilwomanreeves@gmail.com

Plan to Participate in the Title V Air Permit Public Comment Period

Because navigating these dense, highly technical documents can be daunting, GASP is teaming up with our friends at North Braddock Residents for Our Future, CREATE Lab, and other partners to ensure the community isn't left in the dark. Together, we will be providing:

• Timely Notifications: We will let you know when ACHD publishes the draft Title V permit and the public comment period is open.

• Educational Workshops: We'll host sessions to teach you how to read the document and spot key areas of concern.

• Actionable Talking Points: We will share specific language residents can use to demand things like more stringent monitoring, quicker reporting protocols, and tighter emission limits to make the permit more protective of public health.

Understand Your Power to Comment

When a draft Title V permit is released, it triggers a mandatory public comment period. Generally, residents can submit comments in two ways:

1. Attend a Public Hearing and Testify: You can speak directly to regulators, sharing your personal experiences and demands face-to-face.

2. Provide Written Comments: You can submit formal letters or emails detailing technical or community concerns before the public comment window closes.

Why Regulators Need to Hear From You

It is easy to feel like a single comment won't make a difference, but public participation is a vital piece of the regulatory process. Here is why your voice matters:

• It Forces Accountability: When regulators receive a high volume of community comments, they are legally required to review them and publish a formal Comment/Response Document alongside the final permit. Public scrutiny ensures regulators do not simply rubber-stamp weak permits.

• You Provide Crucial Personal Perspective: No one knows the impact of local pollution better than the people living next to it. Telling regulators how industrial air pollution from the Edgar Thomson facility impacts your daily life, limits your time outdoors, or how it exacerbates health issues like asthma provides invaluable context that numbers on a spreadsheet cannot replicate.

• It Amplifies Legal and Advocacy Work: When organizations like GASP push for stronger enforcement or legally challenge a deficient permit, having a record of strong, active community opposition significantly strengthens the case.

Our region has historically faced some of the toughest air quality challenges in the nation, carrying increased risks of respiratory illnesses and cancer.

The good news is that by combining citizen advocacy, community-led education, and public opposition, we can push back against the corporate talking points to ensure our communities get the environmental justice they so richly deserve.