A breach in a recently installed liquid nitrogen system is the suspected cause in a chemical release Thursday morning that killed six workers at a poultry plant in Gainesville, Georgia.
A press conference conducted Saturday by the U.S. Chemical Safety and Hazard Investigation Board reported that a major portion of the liquid nitrogen system at the Foundation Food Group’s Prepared Foods Division, Plant 4, had been commissioned and installed in the last four to six weeks.
At about 10:15 a.m., multiple 911 emergency calls were made to report a hazardous materials situation at the plant. Five employees died at the scene and one transported to Northeast Georgia Medical Center among about a dozen injured later succumbed at the hospital.
About 130 personnel were on duty at the plant at the time of the emergency.
“During this on-scene portion of our investigation, we will not be determining or speculating as to the probable cause,” Katherine Lemos, CSB chairman and CEO told the Atlanta Journal Constitution. “It’s our civic duty to make sure that we consider all of the potentials and not rule out others too quickly.”
Depending on the complexity of the investigation, reaching a conclusion may take as long as several years, Lemos said.
Investigators report that Plant 4 operates five production lines and that the accident occurred on line 4 in which chicken is processed. A release of liquid nitrogen rapidly converted to an inert gas that displaced the available oxygen in the room.
Liquid nitrogen, dispensed by a cryogenic freezer and associated equipment, is used to flash freeze the chicken. The liquid nitrogen is stored in tanks external to the building.
In a description of the incident, the maintenance manager described personally closing the isolation valves of the tanks in the parking lot, shutting off supply to the building.
The site was not cleared as safe for inspection until Saturday morning.
“We are currently working to understand the exact location of the point of release inside the plant,” the CSB statement reports.
Plant 4 receives two to three 18-wheel truckloads per day of liquid nitrogen during normal operations.
CSB investigator Ben Schrader has been placed in charge of the investigation.