LIMOGES, Ont. – Fourteen children fell ill at Calypso Water Park Tuesday because of chlorine vapours pouring out of the pool, officials said.

Thirteen of the children were rushed to the Children’s Hospital of Eastern Ontario after they began choking, vomiting and feeling nauseous.

Staff at Calypso pinpointed the problem after reviewing it.

A technician added 25 kg of 60 per cent concentrated chlorine to the balance tank around 1:04 p.m. when he noticed a leak in the tank. The filtration system was shut down for a 15 minute period to repair the leak, but the chlorine injection pumps continued running, eventually injecting 16 litres of 12 per cent concentrated liquid chlorine into the wave pool.

The chlorine evaporated quickly once it hit the waves, affecting the children, who were all swimming in the same area of the pool. The floor area where the children were swimming, includes several water return pumps, explaining why only those children were affected.

The Eastern Ontario Health Unit has monitored health, safety and water quality at the water park since it opened in 2010.

“We’ve never had any issues with the pools,” said Nicole Laplante, the director of health protection for the EOHU. “They comply with our recommendations and our directives and it’s  unfortunately just an isolated case and a combination of some atypical circumstances that just happened.”

Officials with the EOHU were not able to find the problem, because by the time they took water samples, the extra chlorine had evaporated.

Calypso is apologizing to the public, saying there is a new procedure to follow, which ensures all of the chlorine pumps are turned off when the filtering process is interrupted.

Staff at Calypso did not offer any further comment to a Wednesday afternoon news release breaking down the cause of the problem.

All 13 children have been released from hospital.