Ohio Nitric Acid Leak

Key Facts and Developments

Jun 11, 2025

Incident Overview

A major chemical incident occurred on the morning of June 11, 2025, at the Austin Powder Company's Red Diamond explosives plant in McArthur, Vinton County, Ohio. Around 8:30 a.m., approximately 3,000 gallons of nitric acid leaked from a 5,000-gallon tank, resulting in a significant release of hazardous gases and prompting a large-scale emergency response1 2 5.

Immediate Consequences

The leak produced vibrant orange and brown plumes of smoke, visible for miles, and led to the formation of a toxic nitric oxide gas cloud after a chemical reaction in the tank1 2 4.
The Federal Aviation Administration imposed a temporary no-fly zone over the area, and local authorities ordered mass evacuations, particularly in the village of Zaleski and along several nearby roads1 2 4 5.
Emergency shelters were established at Vinton County High School to accommodate evacuees, with support from the Red Cross and United Way2 4 5.
No injuries or hospitalizations have been reported as of the latest updates1 4.

Health and Environmental Risks

Nitric acid is highly corrosive and can cause severe burns to skin and eyes. The resulting nitric oxide plume can irritate eyes, skin, nose, and throat, and—at higher concentrations—may cause drowsiness or loss of consciousness2 3 4.
Residents were advised to evacuate promptly and avoid exposure. Those experiencing symptoms were instructed to wash affected areas with clean water and seek medical attention if necessary4.
Authorities are also monitoring potential effects on pets and livestock in the affected area4.

Ongoing Response and Monitoring

Hazardous materials teams from multiple counties responded to contain the spill and monitor air quality4 5.
Meteorologists are closely tracking weather patterns, as wind and temperature changes could affect the dispersion and concentration of the toxic plume. Winds have been pushing the plume northeast, but current models suggest it remains largely confined to Vinton County3 4.
Officials continue to monitor the situation, with the duration of evacuation orders dependent on wind conditions and ongoing air quality assessments2 3 4.

Facility Background

The Austin Powder Red Diamond plant manufactures explosives for mining and construction. The facility is located in a rural area, which helped limit immediate residential exposure1 4 5.

Summary Table: Key Details

AspectDetailsLocationAustin Powder Red Diamond, McArthur, Vinton County, OhioChemical InvolvedNitric acid (primary), Nitric oxide (resulting airborne gas)Volume Leaked~3,000 gallons from a 5,000-gallon tankVisible EffectsOrange/brown toxic plume, no-fly zone, mass evacuationsHealth RisksIrritation, burns, drowsiness, possible unconsciousnessEvacuation AreasZaleski, Creek Rd, Morgan Rd, Infirmary Rd, State Route 677Emergency ResponseHazmat teams, FAA, Red Cross, United Way, local and state authoritiesInjuries ReportedNone as of latest reportsOngoing MonitoringAir quality, weather impact, animal health

What Happens Next

Authorities are maintaining evacuation orders and closely monitoring air quality as the situation develops. Residents are urged to stay informed through official channels and avoid the affected area until it is declared safe to return2 3 4 5.

For those in or near Vinton County, continue to follow all local emergency instructions and updates.

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