A federal judge in Pittsburgh has dismissed a Clean Air Council lawsuit alleging U.S. Steel Corp. violated federal law by not reporting excess air pollution in the aftermath of two fires at its Clairton Coke Works.

A Dec. 24, 2018, fire destroyed pollution control systems at the coke works, but the Pittsburgh-based steelmaker continued to use unfiltered coke oven gas as fuel at the Clairton facility and its two Mon Valley steel mills in Braddock and West Mifflin, for 102 days. A second, smaller, fire occurred June 16, and also damaged pollution control equipment and caused excess emissions.

The Washington, D.C.-based environmental organization alleged that the company was required to report the resulting unpermitted releases of hydrogen sulfide, benzene and other coke oven gasses under the Comprehensive Environmental Response, Compensation, and Liability Act, or CERCLA, commonly known as Superfund.

But U.S. District Court Judge Marilyn Horan, in a decision filed Thursday, said that because emissions from the coke works and mills are regulated under the federal Clean Air Act, the company was exempted from the reporting requirements imposed by CERCLA.

The Clean Air Council, represented in court by the Environmental Integrity Project, had argued that the reporting exemption does not apply to pollution emissions that are in violation of existing permits.

According to Judge Horan’s 11-page decision granting the company’s request to dismiss the case, Congress did not specify that the Superfund reporting exemption applied only to permitted pollution emissions, thus the Superfund law “does not require that the air emissions comply with a Clean Air Act permit in order to be exempt.”

“Environmental stewardship is a core value at U. S. Steel,” said Amanda Malkowski a U.S. Steel spokeswoman in an email response to a request for comment. “Following the December 24, 2018 Fire at our Clairton Plant, we made prompt notifications as required by our operating Permits and the Clean Air Act. We respect the Court’s ruling that U. S. Steel made the appropriate notifications under the law.”

Lisa Widawsky Hallowell, senior attorney with the Environmental Integrity Project, said the environmental organizations are reviewing the ruling and could appeal.

“We are disappointed in the decision,” she said in an email, “and are reviewing our options.”

The Clean Air Council is also a plaintiff, along with PennEnvironment, in a federal citizen’s lawsuit filed in April 2019 charging U.S. Steel violated the U.S. Clean Air Act. The environmental organizations, represented by the National Environmental Law Center, said the company’s operations jeopardized the health of Mon Valley residents by continuing production at its coke works and its Edgar Thomson and Irvin steel mills after the December fire.

Sulfur dioxide is one of six primary or “criteria” pollutants regulated by the Clean Air Act, and at high concentrations can affect breathing and aggravate respiratory and cardiovascular diseases, including asthma, bronchitis and emphysema.

In December 2019, U.S. Steel agreed to an $8.5 million settlement of a 2017 class action lawsuit that alleged the company was negligent in allowing air pollution and odors from its Clairton Coke Works to impact residents of the surrounding community. That lawsuit centered on emissions from the coke works prior to the December 2018 fire.