By Logan Andrew, Editor-in-Chief | FreeWire — Your News, Your Voice

McARTHUR, OH— A hazardous chemical leak at the Austin Powder Red Diamond Plant in Vinton County prompted mass evacuations, a no-fly zone, and emergency shelter orders across southeastern Ohio Wednesday morning.
According to state officials, around 3,000 gallons of nitric acid were released from a 5,000-gallon tank just after 8:30 a.m., sending a thick yellow-orange cloud of nitric oxide—a toxic gas—into the air. The incident led to the immediate evacuation of the nearby Village of Zaleski, the closure of surrounding roads, and the establishment of a 30-nautical-mile FAA no-fly zone.
The Ohio EPA said the leak was triggered when an “unknown contaminant” entered the nitric acid tank, initiating a chemical reaction. The resulting gas plume raised serious health concerns. Officials warned that nitric oxide exposure can cause respiratory damage, burning eyes, dizziness, and potentially permanent lung injury.
Roughly 750 residents in the affected area were directed to shelter at Vinton County High School, which was set up as an emergency site. Air monitoring continued throughout the day, and the evacuation order was lifted by 4:30 p.m. after conditions were deemed safe.
No injuries were reported.
The Red Diamond Plant, owned by Austin Powder, manufactures industrial explosives. While the facility has operated in the area for years, this appears to be one of the most serious incidents in recent memory.
Agencies involved in the emergency response include the Ohio EPA, Vinton County Sheriff’s Office, Ohio Emergency Management Agency, Department of Health, and regional hazmat teams. The plant remains shut down while investigators continue reviewing chemical handling protocols and potential violations.
FreeWire will continue to follow the investigation and provide updates as they develop.