CSB Releases Update in Investigation of Virginia Ammonia Release

On Nov. 15, the U.S. Chemical Safety and Hazard Investigation Board released an update (PDF) to its investigation of an ammonia release that occurred on July 31, 2024, at the Cuisine Solutions Inc. food processing facility in Sterling, Virginia. Ammonia is a chemical often used in refrigeration systems. When inhaled, ammonia may cause headaches, nausea, vomiting, coughing, wheezing, and irritation of the throat, and the substance is considered immediately dangerous to life and health when present at high levels. All 286 employees and contractors at the Cuisine Solutions facility evacuated when the release was discovered, CSB reports. There were no fatalities, although 40 people were evaluated at local medical facilities and four people were admitted to nearby hospitals.

At the Cuisine Solutions facility, ammonia refrigerant was used to cool water used in the food preparation process. On the evening of July 31, a Cuisine Solutions employee reported smelling a chemical odor and experiencing tearing eyes, throat irritation, and difficulty breathing outside the building, near the main employee entrance. Maintenance workers investigating the report a few minutes later observed a white cloud emerging from the ammonia system located near the west side of the building. Meanwhile, people inside the facility identified an ammonia odor, and the site manager instructed all personnel to evacuate the building through exits on the east side, but some mistakenly evacuated through exits near the ammonia release and were exposed to ammonia vapor. Initially, all personnel gathered at a muster point to the east of the building, but due to the prevailing wind, they were still able to smell ammonia and eventually relocated a short distance away. Employees called emergency services and assisted the Loudoun County Fire and Rescue Hazmat Team in isolating an emergency pressure release valve which had released the ammonia. Emergency services then ventilated the building to remove the remaining ammonia.

Further information about CSB’s investigation and a link to download the update may be found in a CSB news release.