On the morning of June 11, 2025, a significant chemical leak at the Austin Powder Company’s Red Diamond facility in Vinton County, Ohio, triggered widespread emergency evacuations and a swift response from local authorities and environmental agencies. The incident involved the release of approximately 3,000 gallons of nitric acid from a 5,000-gallon storage tank, setting off a chemical reaction that produced a plume of nitrogen oxide gas, visible as an ominous orangish-brown cloud over the region.
The leak was first reported around 8:30 a.m., when crews discovered the nitric acid escaping from the tank at the explosives manufacturing plant located at 32000 Powder Plant Road in McArthur, Ohio. Austin Powder, headquartered in Cleveland, is one of the few U.S. companies that produce industrial explosives used primarily in mining and construction, employing about 250 people at this facility.
Initially, there was some confusion regarding the volume of the leak. Emergency management officials first reported a leak involving 50,000 gallons, but this was later corrected to 3,000 gallons leaking from the 5,000-gallon tank. The Ohio Environmental Protection Agency (EPA) clarified that an unknown contaminant had entered the nitric acid tank, causing a chemical reaction that released nitrogen oxide gas into the atmosphere.
The nitrogen oxide plume was visible from miles away, painting the sky with a striking red-brown hue. This hazardous gas is known to cause a range of health issues, including irritation of the nose, throat, and lungs, coughing, shortness of breath, fatigue, and in severe or prolonged exposures, permanent lung damage. Other symptoms include skin and eye irritation, headaches, dizziness, and even a bluish discoloration of the skin. Officials warned that fluid buildup in the lungs might be delayed, making it imperative for anyone experiencing symptoms to seek immediate medical attention.
In response to the leak, emergency services acted quickly to protect residents. The Vinton County Sheriff’s Office issued evacuation orders for the village of Zaleski, a small community of about 216 residents, as well as surrounding areas including Powder Plant Road, Morgan Road, Infirmary Road, Creek Road, and State Route 677. The American Red Cross opened a shelter at Vinton County High School for those displaced by the evacuation. Some residents were also advised to shelter in place, particularly in areas where the plume was expected to drift.
Fire departments deployed drones to monitor the affected area, while air quality sensors conducted rigorous testing. Fortunately, no positive readings for nitrogen oxide were detected beyond the immediate vicinity of the plant, and the plume gradually dissipated over the course of the day. By approximately 4:40 p.m., the Zaleski Fire Department lifted the evacuation orders, allowing residents to return home safely.
Throughout the incident, no injuries were reported among plant workers or residents. The plant's spokesperson confirmed that all employees were accounted for and safe, with most being sent home temporarily while a smaller team remained to assess the situation. Production at the facility was suspended for the remainder of the day as a precaution.
Public officials emphasized the importance of following safety instructions during the emergency. State Senator Shane Wilkin urged residents to heed the guidance of local law enforcement and emergency personnel, stating, “Public safety is of the utmost importance. I urge those affected to listen to the local sheriff’s office and other emergency personnel on what to do and how to proceed during this emergency.” Similarly, Ohio Republican Senator Jon Husted announced that his office was closely monitoring the situation and coordinating with federal, state, and local agencies.
The Ohio Department of Transportation reported closures of State Routes 328, 677, and 278 due to the emergency, with no immediate timeline for reopening. Meanwhile, the Federal Aviation Administration established a temporary flight restriction covering a 30-nautical-mile radius around the plant to ensure airspace safety during the incident.
Environmental and public health authorities reassured the community that private and agricultural water wells were not contaminated, with no evidence suggesting that water supplies were unsafe for consumption. The Ohio EPA pledged to continue air quality monitoring until the situation was fully resolved.
Wind conditions played a critical role in the incident’s impact. The National Weather Service in Charleston, West Virginia, provided plume trajectory updates, which showed the nitrogen oxide cloud moving southward from the plant. Officials noted that the timing for residents to return home depended largely on these wind patterns and the dissipation of the hazardous gases.
While the exact cause of the nitric acid leak remains under investigation, authorities confirmed that the chemical reaction within the tank was triggered by an unknown contaminant entering the nitric acid process tank. The incident serves as a stark reminder of the risks associated with chemical manufacturing and the importance of stringent safety protocols.
Residents in Vinton County and surrounding areas have been advised to remain vigilant for any symptoms associated with exposure and to consult medical professionals if concerns arise. The community’s calm and orderly response, combined with the rapid actions of emergency responders and plant personnel, helped prevent injuries and minimized the incident’s overall impact.
As Austin Powder and regulatory agencies work to determine the leak’s cause and prevent future incidents, the event underscores the delicate balance between industrial activity and community safety in rural America.
