Investigation concluded on fatal ammonia leak in B.C.

Following a six-month investigation, Technical Safety BC has released its findings on the fatal ammonia incident that occurred on May 26 in Kamloops, B.C.

The report, titled “Kamloops Ammonia Release” was based upon evidence presented and available at the time of the investigation, which sought to understand both causal and contributing factors that led to the ammonia release, according to Technical Safety BC.

The facts

The incident occurred on May 26 when a crew was in the process of cutting up and disassembling two ammonia refrigeration systems at an Artic Glacier Inc. ice distribution facility located in Mount Pail Industrial Park, located on Tk’emlúps te Secwépemc reserve in Kamloops, B.C.

According to the report, the crew believed that all ammonia had been removed from both systems. During the removal of a section of one of the systems containing the receiver and compressor, it was identified that a valve handle protruded past the frame and could cause issues with the rigging process.

“Options to deal with the protruding part, such as turning it, were being discussed and one of the individuals turned the valve handle, resulting in a large release of ammonia,” states the report. The individual who turned the handle was sprayed with ammonia and moved further into the building, while the remaining crewmembers evacuated through a nearby door.

The individual who opened the valve was later pronounced dead following the incident. Multiple others were exposed to the ammonia, and a local evacuation was issued.

Follow-up

Technical Safety BC found that the primary cause of the incident was a failure to remove ammonia from the refrigeration system ahead of its disassembly. The investigation concluded that the ammonia release occurred when a ball valve holding back pressurized ammonia for the entire system was opened. However, those working on the disassembly understood the system to have been previously emptied.

The investigation concluded that up to 1,000 pounds of ammonia was dissolved into water and released directly into the facility parking lot during a 16.5-hour purging operation of the system between May 25 and May 26.

During the fatal incident, it was calculated that between 1,300 and 1,645 lbs of ammonia were released from the receiver when the valve was opened. This amount was calculated from an analysis of the release and is consistent with the investigation findings that no ammonia had been removed from the vessel since it was shut down in late 2015.

The report states that several contributing factors led to this fatal incident, including miscommunication, staffing changes, and failure to involve a licensed refrigeration contractor to conduct a complete assessment for the presence of ammonia.

From its report, Technical Safety BC posed several learning and recommendations following the fatal incident. This includes ensuring a functional exhaust system is in place as this may have reduced the probability of an explosion occurring after the release.

during an instantaneous release of 6,000 lbs. of refrigerant with levels of 35, 300 and 1,200 parts per million (ppm).

The explosion occurred when the ammonia released from the system was only partially contained and came in contact with a source of ignition, which resulted in an explosion and damage to the facility. The ventilation system was also non-functional due to the assumption that no ammonia was present in the facility. A functional ventilation system would have likely lessened the amount of time that the ammonia concentration was combustible, but it likely wouldn’t have prevented ammonia concentration from reaching explosive limits.

Recommendations

Technical Safety BC recommends that only those with the necessary skills and knowledge should be conducting activities with hazardous work. This principle applies throughout the life cycle of regulated systems, including the dismantling and decommissioning stage, and licensed contractors must validate that ammonia and oil have been removed from a system and that equipment is ready for disassembly and transportation.

The report adds that when planning for and facilitating the final shutdown and disassembly of refrigeration equipment, owners and managers directly engage a licensed contractor to validate that both ammonia and oil are removed; and that equipment is ready for safe disassembly and transportation.

Additionally, Technical Safety BC recommends that Canadian Standards Association (CSA) adopt or develop requirements for the dismantling, disassembly and decommissioning of refrigeration systems and equipment.

Plumbing & HVAC previously reported on the ammonia leak in Fernie, B.C. back in 2017, which killed three people. For more information regarding ammonia safety, check out our “Ammonia System Safety” articles, written by Greg Scrivener. :