Response to an NH3 leak leads to serious exposures and missed shifts

At approximately 9:30 p.m. on or about July 31, Employee #1, a can and bottling operation maintenance technician, responded to a possible ammonia leak during the second shift at the plant. A 2,000-lb outside storage tank pumped ammonia into the line-filled room to cool the syrups to between 35 and 40 degrees F before the cans and bottles were filled. Part of the XXXXX valve, which controlled the line flow, broke, and ammonia leaked into the air.

Employee #1 arrived and entered the maintenance room WITHOUT ANY RESPIRATORY PPE. Once the supervisor was present, however, all the maintenance technicians donned respirators and were able to isolate the line where the leak occurred. The plant was evacuated and the lead maintenance technician and the second shift supervisor toured the facility with ammonia strips to determine whether it was safe to re-enter.

Ammonia was detected throughout the plant, so the second-shift employees were sent home, and all the doors were opened to allow the buildings to air out. Employee #1 said he felt nauseous and had a headache, and the supervisor sent him to the Emergency Room.

After determining the plant was safe to enter, the supervisor and maintenance lead decided to allow the third shift to begin work. Shortly thereafter, several employees in different parts of the building began to experience burning sensations on their faces, noses, and respiratory tracts. Even after stepping outside, these employees did not feel better, so the supervisor sent them to the hospital as a precaution. The supervisor and maintenance lead then called the plant manager and requested permission to send the third shift home.

Employee #1 and coworkers were treated and released, although the doctor instructed Employee #1 to take one day off from work. The location of the ammonia leak was in the compressor room, not the filler room, where there was a control panel that would shut down the system if a drop in pressure was detected, as happened in this case. Preventive maintenance was performed on the regulator valves but not on the gaskets.

In this case, the failure occurred due to a pinhole in a gasket. According to the lead maintenance technician, there was no way to prevent the occurrence. Because the refrigeration system was a closed loop, the tank had never been refilled in the three years the plant has been in operation. It was later determined that between 50 and 75 lb of hot vapor had been released.