An alarm was the first indication of any problems at the Comox Valley Sports Centre Thursday night, alerting staff that ammonia was leaking inside a compressor room. 

Deputy Fire Chief Kurt MacDonald said arena staff immediately began clearing the building.

"Upon arrival we found that the arena had been evacuated by arena staff and that a small leak was detected in the compressor room," MacDonald said.

Both rinks and the pool were in use by the public at the time and meetings were taking place inside the building.

"Arena staff did an excellent job getting people out of the building prior to our arrival," MacDonald said.

Cameron Knox was at the arena getting ready for the start of an old-timer's pickup hockey game.

"I just got into the rink and I put my gear down and the rink attendant came in and [said], 'Get outside right away, there's an ammonia leak.'"

Knox said other players left with their gear but left their keys inside and had to wait for about an hour while maintenance crews fixed the problem.

Emergency crews and arena operators have a heightened sense of urgency around leaks following the death of three maintenance workers in Fernie in October 2017.

The trio were inside an enclosed room at the Fernie Memorial Arena when ammonia leaked from the cooling system, killing the three men and triggering the evacuation of 55 nearby homes.

In the Thursday incident, both entrances to the sports centre were blocked off to keep the public away from the facility.

"Obviously if you do have a leak you have to take it seriously. Fortunately this one appears to be very small and again it was contained to the room of origin, but best case scenario for sure," MacDonald said.