Three pool employees were sent to hospital Thursday after they inhaled ammonia gas following a suspected chlorine leak.
Nanaimo Fire Rescue responded to the incident shortly after 1 p.m. and arrived to find people being evacuated from the building.
"Ammonia is basically gaseous chlorine," said Martin Drakeley, Nanaimo Fire Rescue assistant chief of operations. "When it reacts with moisture it turns into hydrochloric acid and forms burns."
One female lifeguard was being taken to Nanaimo Regional General Hospital when firefighters arrived.
Her injuries were reported as not serious and the trip to the hospital was precautionary. Two other employees were taken to hospital, also as a precautionary measure after developing respiratory symptoms, Drakeley said.
The chlorine leak was small and the result of maintenance work being done on a supply line.
"If there was a leak, it was basically just what was left in the line," Drakeley said. "Maintenance staff were on it immediately and it was looked after."
No visitors to the pool were injured and portions of the Beban Park complex were being reopened by about 2:30 p.m.