More than a dozen children were treated by paramedics after what police are calling a chemical spill involving chlorine at a Burlington park.

Emergency services were called to the LaSalle Park just after 2 p.m. after pool staff noticed an odour and evacuated about 40 people, according to city spokesperson Carla Marshall.

Fourteen people were assessed at the scene by paramedics, says Chief Greg Sage.

Six of those people were taken to local hospital in stable condition. One person was transported to McMaster Children's Hospital in "more serious condition," he said.

"All of them [were] complaining of inhalation-type injuries, nausea, vomiting, light-headedness, decreased level of consciousness," said Sage.

City reviewing incident

Halton Regional Police Insp. Ivan Lortie said it's his understanding there was "some kind of chemical spill" and in a tweet the police service referred to reports of "chlorine contamination."

"It appears that there was some kind of inadvertent chemical injection of chlorine into the pool," explained Lortie.

Police say some sort of equipment failure may be to blame of injecting chlorine into the pool. (Jeremy Cohn/CBC)

The city says it has determined that water levels dropped during routine maintenance, causing "higher than normal levels" of disinfectant to enter the water.

Disinfectant levels were "still within the recommended range," said Marshall, but they have since been lowered even further.

"The City is reviewing this incident to prevent future incidents," she said. "[Burlington] would like to thank first responders for their speedy response and wish everyone a speedy recovery."

The City is reviewing this incident to prevent future incidents. <a href="https://twitter.com/BurlingtonFire?ref_src=twsrc%5Etfw">@BurlingtonFire</a> inspected and tested the entire perimeter of the pool for air quality and deemed all levels to be safe. —@cityburlington

Eight ambulances were called to the scene, along with an incident commander and a mobile command post to help provide space for people to cool down.

"Pediatric patients can be more challenging, but our staff are obviously trained to deal with them both from an emotional and clinical perspective," said Sage, adding emergency crews regularly practice their response to incidents with multiple casualties.

Pool expected to reopen Wednesday

The Burlington fire department has tested the air quality along the entire perimeter of the pool and found all levels were safe, said Marshall.

Members of the region's health department are still on scene. The wading pool and splash pad are expected to reopen tomorrow at 11 a.m., Marshall added, "once it has been tested, inspected and confirmed safe."