Lessons from a Confined Space Tragedy

By Ed Rutkowski

June 11, 2026—In November 2018, three employees of an Alberta cryogenics facility died after exposure to nitrogen gas in a confined space. This incident was the focus of an educational session last week at AIHA Connect in New Orleans that showed how deficiencies in process design and training contributed to the tragic outcome. 

The presenter, Robert Waterhouse, is the principal consultant with Energy Safety Canada, the national safety association for the Canadian energy industry. Waterhouse began the session by playing an animated recreation of the accident produced by Energy Safety Canada. 

Based in LeDuc, Alberta, the facility used nitrogen to freeze metal pipes and other equipment intended for the oil and gas industry. According to a report on the incident from the government of Alberta, the freezing process allowed the rubber linings and coatings on the equipment to be removed more easily. The freezing apparatus involved two coolers in which equipment was placed, a transfer duct, exhaust ducts, and valves governing the flow of nitrogen that needed to be manually adjusted. Following a cooling cycle, which typically occurred overnight, workers would use compressed air to purge the nitrogen and lower an instrument into the cooler to monitor its oxygen levels. Once the oxygen reached a safe level, workers would enter the cooler for the purpose of removing equipment, which sometimes required the use of slings and a front-end loader.

On the day of the incident, workers determined that some previously frozen equipment needed to be refrozen. The equipment was placed in one of the coolers, but the valves were not set properly. Later, this oversight allowed nitrogen to flow into the cooler at the same time a worker entered to apply a sling to the frozen equipment. As the worker knelt to secure the sling, he breathed in nitrogen, became hypoxic, and lost consciousness. The worker’s supervisor and a coworker subsequently entered the cooler and were also overcome by nitrogen. All three were dead by the time emergency responders arrived.

One lesson from the incident, Waterhouse said, concerned the critical importance of a fail-safe capability—that is, the automatic return to a safe operating condition when an error is made. At the cryogenics facility, a fail-safe would not have allowed the system to operate with the valves incorrectly configured. Ventilation, alarms, and worker training on hazards and the proper use of personal gas monitors were also glaring omissions.

While the system’s design was unsafe, several factors contributed to the incident. During discussions with the facility’s employees, Waterhouse learned that the company wasn’t aware of regulations governing confined spaces. Someone who wishes to start a cryogenics business will not be prompted to learn about applicable regulations and possible hazards, Waterhouse said. The workers themselves seemed not to believe how quickly they could become incapacitated by nitrogen; one or two breaths is all it takes, Waterhouse said, to cause a rapid drop of oxygen to the brain. “People think, ‘I can hold my breath for several minutes. What’s the big deal?’”

The complexity of the process also came under scrutiny. Refreezing equipment was a departure from standard practice and meant that the workers’ mental model of the process was no longer valid, which could explain why they didn’t adjust the valves. “A lot of the solutions to complexity are actually transparency,” Waterhouse said. “You can’t make complex things simple, but you can make them transparent.” He suggested that a wall-mounted display of the nitrogen supply and the positions of the valves may have helped the workers recognize the danger.

Waterhouse encouraged participants to share information about incidents such as the LeDuc fatalities to ensure they aren’t repeated. The conditions that led to the tragedy are likely to exist in other workplaces, he said, and shouldn’t be dismissed because they occurred at a unique facility. “We’ve got to be way more open to actually learning from others’ experience.”

Ed Rutkowski is editor in chief of The Synergist.