Liquid nitrogen leak kills six, injures 12 at US food processing plant
29 January 2021
Six people died and 12 others were hospitalised on January 28 after a liquid nitrogen leak occurred at a poultry plant in the state of Georgia, US. Local fire and police officials confirmed that five people died at the scene while one person died after being transported to hospital. Three of the injured are in critical conditions, five are stable, and three others have been treated and released.
Representative image: Shutterstock
The incident happened at a plant belonging to the Foundation Food Group in Gainesville, around 60 miles (97km) north of Atlanta. Foundation Food Group Vice President Nicholas Ancrum told reporters that an initial inspection suggested that a nitrogen line had burst. A full investigation by the local police and fire department is underway.
The US Chemical Safety and Hazard Investigation Board (CSB) said it two of its investigators would deploy to the scene and its CEO and Chairman, Dr. Katherine Lemos, would also attend the site.
Authorities were called to the site at around 10:12 local time and said the incident required a hazardous materials response within 10 minutes of arriving. Four firefighters were among those injured after suffering from respiratory problems.
The bodies of those who died at the scene were removed from the plant later in the day once it had been made safe. The Foundation Food Group did not disclose the identities of those who died but said among them were maintenance, supervisory and management team members.
Local school buses were used to evacuate around 130 people to a local church where they underwent medical evaluations. The fire department said that no explosion occurred during the incident.
Local media report that the plant where the leak happened was a Prime-Pak Foods facility until it merged into the Foundation Food Group on January 1. The plant processes raw chicken into products frozen products for restaurants and food service companies.
Liquid nitrogen is often used in food processing plants as a refrigerant. If it leaks into an enclosed environment, it can quickly displace oxygen and can lead to death by asphyxiation. In December 2020, there was a liquid nitrogen leak at a food processing plant in Vernon, Los Angeles which killed two workers. The incident at the Golden West Food Group plant remains under investigation after Hazmat teams were unable to determine the source of the liquid nitrogen and did not detect abnormal levels of liquid nitrogen in the area where the two employees were found.
In a statement on February 1, the CSB provided some initial facts regarding its investigation into the liquid nitrogen (LN) release at the Foundation Food Group’s Gainesville plant. As a matter of orientation, the CSB said that the event occurred on Line 4, where chicken is processed, to include seasoning, cooking, freezing, and then packaging. CSB investigators are focusing on the cryogenic freezing system, based on information from various sources.
The CSB released the following new facts on the incident:
- CSB has now confirmed that both the external and the interior elements of this system were manufactured by Messer. This includes the supply tanks outside, and the interior cryogenic freezing equipment on Line 4.
- Prior to the recent installation of this system, a different type of freezing equipment was used, which was ammonia-based. This equipment is still collocated on Line 4 adjacent to the cryogenic system and has not yet been removed.
- The approach of using LN was introduced to Plant 4 in 2020, as it is also being used on Line 2 in Plant 4.
- Some tools were located in the vicinity of the Line 4 immersion freezer. The CSB has since learned that unplanned maintenance was being conducted on Line 4.
The system installed is a LN immersion-spiral freezer. This process occurs in two stages. In the first stage, the chicken travels on a conveyer belt and is submerged in LN at a temperature of -320F. In the second stage, the conveyer belt travels through the spiral freezer portion, and the chicken is exposed to recovered gaseous N (from stage 1), to complete the freezing process.
The CSB added that on January 31, two additional patients were released from the hospital, and the remaining patient is in fair condition (previously critical). The CSB will continue to provide updates as the investigation progresses.