The leak occurred Tuesday afternoon in the wave pool of the Calypso Water Park and affected the children, who were taken to hospital with mild injuries but later released.
Calypso says in a release that a filtration system was shut down for 15 minutes, allowing a build up of liquid chlorine that was then injected into a section of the pool.
The chlorine emitted vapour when it hit the water's surface, irritating the airways and eyes of the children, and also causing nausea.
The Eastern Ontario Health Unit tested the air and water after the chlorine release but did not find abnormal chemical levels.
The water park says it is sorry for the incident and that it has adjusted its procedures to ensure chlorine is not injected into the water when the filtration system is stopped.
(The Canadian Press/CFRA)