A massive ammonia leak late Wednesday night in Weatherford, Oklahoma sent dozens to the hospital and forced hundreds of residents to evacuate their homes, according to local authorities. Officials lifted evacuation orders Thursday morning after air quality levels returned to safe conditions. Weatherford, a city of about 12,000 residents, is located roughly 70 miles west of Oklahoma City
The incident began around 10 p.m. when an 8,500-gallon tanker truck parked outside a Holiday Inn Express began leaking anhydrous ammonia, a toxic chemical commonly used in fertilizer and industrial applications. Weatherford Police Chief Angelo Orefice said crews quickly responded and managed to stop the leak. However, before the situation was contained, a thick plume of gas spread across a wide area, forcing emergency evacuations.
Weatherford Emergency Manager Mike Karlin said that “as the event unfolded, we had a large plume of anhydrous ammonia gas spread over a pretty large area.” Karlin estimated between 500 and 600 people were displaced, though Orefice noted the number was likely closer to 300–500 as the situation evolved.
Anhydrous ammonia, a colorless gas with a pungent odor, can cause severe burns and respiratory damage upon exposure. While commonly used in fertilizers for crops such as corn and wheat, it poses serious health risks in concentrated form. Authorities confirmed that approximately 36 people received medical attention, with 11 transported to nearby hospitals and four airlifted to Oklahoma City in critical condition. Residents reported experiencing severe respiratory distress as first responders went door to door in gas masks, warning people to evacuate.
Emergency alerts were sent out shortly after the leak, instructing people to “Evacuate north to Davis Ave and from Washington Ave to Lyle Rd. Safety location is Pioneer Cellular Center. If you are having medical symptoms, call 911, or medical personnel located at Ace Hardware.”
Several nursing homes were cleared, and both Southwest Oklahoma State University and Weatherford Public Schools canceled classes Thursday. The university advised, “First responders on scene have recommended that all students in SWOSU on-campus housing shelter in place due to the fumes. Students in residence halls should remain indoors, keep windows and doors closed.”
A public safety notice also urged businesses and residents in certain areas to stay indoors until further notice. Interstate 40 exits leading into Weatherford were temporarily closed, and hazmat teams worked through the night alongside the Oklahoma National Guard to contain and neutralize the leak. Officials said calm winds initially slowed efforts to disperse the gas, but by early Thursday the air was deemed safe, and residents were allowed to return. Orefice advised that any clothing worn during the incident be placed outdoors to allow remaining ammonia residue to dissipate.
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