Police have set up a 300-metre perimeter around a water-treatment plant on Ashbridge's Bay after a regular chemical mixing produced chlorine gas, a potentially deadly chemical.
There is no public health risk, according to Toronto Fire, and all employees are safe and accounted for.
At 8:48 p.m., fire officials got reports of a possible chemical hazard at the Ashbridges Bay Water Treatment Plant, said Toronto Fire's Adrian Ratushniak. Sodium chloride had been poured into the wrong container, he said.
"It was initially thought that could be a really bad thing, but as we've investigated and done air sampling, we've found there's no airborne risk at all, no injuries."
There is no gas spill, leak or airborne risk, he added.
Firefighters have put on chemical suits and entered the building to investigate, he said.
"We're in the process right now of standing by while the engineers of the plant go through and do their assessments and readings," Mr. Ratushniak said.
He could not confirm the type of chemical that was produced, but Staff Sergeant Peter Troup, who's officers are on scene, says it is chlorine gas.
"I believe it does have an odour," he said.