Six people were taken to hospital Saturday after breathing in noxious fumes at a Toronto gym.
Canada Journal reports that the gym was evacuated, citing Toronto emergency services.
Police say man in his 20s and a man in his 30s are both listed in serious condition and will be held overnight for observation.
Paramedics say 16 other people were transported onto a TTC bus for shelter and are said to be doing fine.
Fire officials say the fumes were the result of a human error when chlorine was mixed with a salt solution.
Toronto Fire has aired out the building and cleared the scene.
The GoodLife facility has been closed down for the day.