Niagara Regional Police confirmed there was a fatality as the result of an ammonia leak at Rich Products of Canada, a food factory in Fort Erie near the U.S. Border.
Two more people were taken to hospital, however police said their injuries were "non life threatening" in a Facebook post Monday afternoon.
Niagara Fire platoon chief Dave Belme said his department has sent a hazmat team to do a "secondary search" of Rich Products of Canada.
Belme and Niagara Police said the leak has been stopped and there is no public risk. Some streets around the factory remain closed.
Belme also said the Niagara Fire Department was there supporting the local Fort Erie Fore Department, which tweeted out that two patients were initially removed from the site, and that "additional patient(s) has been removed from Rich Products."