An explosion caused by an ammonia leak injured one employee at a food supply facility in Elk Grove Village, Illinois. A hazmat worker was also hospitalized for exhaustion.

According to fire officials, ammonia began to leak inside Grecian Delights and came into contact with a source of ignition, triggering an explosion that blew off part of the building’s façade. About 100 people were working in the plant at the time and were evacuated. Officials said the ammonia likely was used in the building’s refrigeration system.

The injured worker was burned in the explosion and taken to Alexian Brothers Medical Center for treatment of non-life-threatening injuries.