U. S. Steel's is committed to environmental progress. We strive for 100% compliance with all federal, state and local agencies’ rules, regulations and permit conditions, even as regulations become more stringent. An important part of that progress and compliance is working to continuously improve our operations with regard to air quality.

In 2021, we set a goal to reduce corporate nitrogen oxides (NOx) emissions intensity by 10% by 2030 compared with our 2018 baseline. That goal amounts to cutting intensity by 174 net tons per million metric tons of crude steel produced. In 2023, our absolute NOx emissions intensity was 1,697 net tons per million metric tons of crude steel produced. Steel production increased which resulted in a slight decrease of our NOX intensity as compared to 2022.

However, we are still on target to meet the 2030 goal by:

  • Shutting down Clairton Coke Batteries facilities 1, 2 and 3 in early 2023
  • Following our enhanced maintenance and fuel use strategy; and
  • Establishing and tracking metrics
  • For the calendar year 2023, our compliance rate for coke oven battery under fire stacks was 99.8%.

For federal coke battery standards, our compliance rate was 100%. Based on actual monitoring data from the last three years, Allegheny County, including the area in which the coke plant is located, has met all federal National Ambient Air Quality Standards.

To see our air quality-related highlights, goals and progress, click here.


Air Emissions (U.S. tons)202120222023

Clearing the Air: Positive Trends in Pittsburgh Region’s Air Quality

In 2023, the fourth Clearing the Air report was published. The report was issued by Pittsburgh Works Together, an organization comprising business and labor leaders throughout the Pittsburgh region, of which both U. S. Steel and the United Steelworkers are members. Utilizing U.S. Environmental Protection Agency (EPA) data from 2022, the report provided the welcome news that the Pittsburgh region’s air quality has been improving year after year.

Other key findings in the report include:*

  • The region’s average level of microscopic soot (PM2.5) continues to decline. The PM2.5 level near
    U. S. Steel’s Clairton Plant has met EPA standards for years, and it declined 7% in 2022 compared to 2021, and dropped 23.2% over the past decade.
  • For the first time ever, Allegheny County has been in compliance with EPA National Ambient Air Quality Standards for two consecutive years.
  • The Pittsburgh region is one of the cleanest major metro areas for ozone, having less ozone than 74% of the 50 largest metropolitan regions in the country.


U. S. Steel Digital and Analytical Forecast Model

Weather can heavily impact the levels of particulate matter. That means being able to predict what’s going to happen with the air around a plant in the coming hours can provide an opportunity to help the region’s air quality while facing weather challenges.

To do exactly that, we developed an internal U. S. Steel Digital and Analytical Forecast Model to predict the probability of exceeding PM2.5 thresholds four hours in advance of certain weather shifts. This model incorporates data from Clairton Plant operations, regional and local weather stations and local air quality monitoring. The results allow us to analyze data quickly in response to an ambient air quality event; to predict the potential air quality impact under different operational parameters and weather conditions; and to proactively control operational parameters in response to a forecasted weather condition.

Our custom machine-learning model underwent yearlong training periods to test accuracy and refine performance. The model produces a dashboard of output visualizations for current weather and operational values, model performance and feature relevance, as well as prescriptive analytics to identify the effect on PM2.5 values. The dashboard is updated every 15 minutes, while predictions are updated every hour. We routinely hold meetings with subject matter experts to assess the models’ data and findings during inversions.

We expect to rely on the model to help us stay ahead of weather events and do the best job of being a partner to help protect the air around our plants.