Washington, D.C., June 24, 2025 — The U.S. Chemical Safety and Hazard Investigation Board (CSB) announced today that the agency has launched a formal investigation into two incidents involving toxic nitric acid at facilities owned by the Austin Powder Company: (1) the June 11 release of toxic nitrogen oxide gas at the company’s Red Diamond facility, an explosives manufacturing plant near McArthur in Vinton County, Ohio, and (2) a similar gas release that occurred on November 24, 2024, at the U.S. Nitrogen facility in Midway in Greene County, Tennessee, which Austin Powder owns. The CSB conducted initial fact-finding at the Ohio facility last week.
According to a statement issued by Austin Powder, the June 11 incident at the Ohio facility occurred after “an unanticipated chemical reaction” in a 5,000-gallon storage tank containing nitric acid “generated” nitrogen oxide gas that was released to the air. A large, yellow-brownish-colored plume of gas covered the facility and much of the surrounding area. Local officials ordered an evacuation of a 3-mile radius around the facility, and hundreds of residents in the nearby community of Zaleski also were later evacuated. Additionally, local media reported that the Federal Aviation Administration temporarily restricted flights for a 30-nautical-mile radius surrounding the facility.
The November 24 incident at the company’s U.S. Nitrogen facility in Tennessee occurred after a “malfunction” during a start-up of the facility’s nitric acid plant, according to a statement issued by Austin Powder at the time. The Tennessee facility produces nitric acid and other substances that are used in other products manufactured by Austin Powder. Like the June 11 incident in Ohio, a similarly colored large plume of gas was emitted during the November 24 incident in Tennessee.
CSB Chairperson Steve Owens said, “We are concerned that incidents involving nitric acid have occurred at two facilities owned by Austin Powder in less than seven months. While fortunately no one was injured in either incident, we want to ensure that they do not continue to happen.”
The CSB is an independent federal agency responsible for investigating industrial chemical incidents that result—or could result—in catastrophic releases of hazardous substances. The Board conducts thorough investigations, issues safety recommendations, and advocates for preventive measures to protect workers, communities, and the environment.
Board members are appointed by the President and confirmed by the Senate. The CSB does not issue fines or citations but makes non-binding safety recommendations to companies, labor organizations, regulatory bodies, and industry stakeholders.
For more information, visit www.csb.gov or contact Communications Manager Hillary Cohen at [email protected].