Through a process of elimination, a malfunctioning ice-resurfacing machine is believed to be the culprit in a carbon monoxide poisoning incident Saturday at a private ice arena.
The arena was was to reopen Tuesday evening after safety agencies gave approval.
B.C. Safety Authority released a statement earlier in the day saying it has ruled out any fixed equipment at the area utilizing gas as a cause. The refrigeration plant utilizes a heat pump and cannot emit carbon monoxide, it said in a statement.
Dawn Couture, manager at Ice Box at Mount Paul Industrial Park, said the ice resurfacer likely caused elevated levels of carbon monoxide.
WorkSafeBC said it has ensured the resurfacing machine will be serviced and maintained and monitoring equipment calibrated and utilized.
Fifty people were taken to Royal Inland Hospital with symptoms of carbon monoxide poisoning Saturday. All were released by the next day. Symptoms included headaches, nausea, dizziness and confusion among adult hockey players in a corporate tournament.
"That's what it's looking like now," Couture said of the ice resurfacer.
Repairs have since been done on the machine.
Incidents of carbon monoxide poisoning are not uncommon in North American arenas. Seven years ago, 21 people were taken to RIH after showing symptoms of carbon monoxide poisoning at Chase's Art Holding arena.
The risks inside arenas are well known in the industry.
Jeff Putnam, business and client services manager with the City of Kamloops, said the risk from carbon monoxide is a slow buildup rather than a sudden release.
The odourless, colourless gas, a byproduct of combustion, binds with oxygen to create carbon dioxide, thus robbing the indoor space of breathable air.
The City does weekly testing with portable monitors. Any readings above .5 parts per million (ppm) requires notification to a superior and potential action.
As an additional precaution the City is now installing permanent detectors in boiler rooms inside arenas. At Interior Savings Centre the City uses an electric ice resurfacing machine. At the two smallest arenas, ventilation fans operate when a machine cleans the ice.
Couture said the privately operated Ice Box has handheld carbon monoxide detectors.
"They're in the building all the time. We do test now and again."