On July 31, 2024, a hazardous ammonia release at the Cuisine Solutions food processing facility in Sterling, Virginia sent 40 people to hospitals — four were admitted, including one to the intensive care unit. The facility employed approximately 350 workers and operated large-scale ammonia refrigeration systems approximately 30 miles from Washington, D.C. The release occurred when an ammonia refrigeration system pressure relief device (PRD) discharged — but instead of releasing vapor only, it released liquid ammonia in a two-phase flow, creating a dense, ground-level ammonia cloud far larger and more hazardous than a vapor-only discharge.

The Emergency Action Plan (EAP) at Cuisine Solutions did not distinguish between indoor and outdoor ammonia releases — two scenarios requiring different responses. No ammonia-specific alarm existed to tell workers what to do. Workers evacuated through areas with elevated ammonia concentrations because the EAP lacked wind direction guidance, alternate routes, and shelter-in-place criteria. The confusion during the response converted a containable process safety event into a mass casualty incident.

The CSB's final report (released September 25, 2025) found that the pressure relief system for the horizontal surge drum was not designed to prevent liquid/two-phase discharge — a gap in both facility design and industry standards. Six recommendations were issued covering relief system redesign, emergency planning, and process data collection.