Public health officials in Toronto have identified a Toronto Transit Commission cooling tower as the source of a recent outbreak of legionnaires’ disease.
Officials said they investigated an outbreak of six confirmed cases within about a one-kilometre radius of the intersection of Bathurst and Dupont streets.
They said a cooling tower at the TTC’s Hillcrest Complex was determined to be the source of the outbreak after samples collected from the tower matched a sample from a legionnaires case.
“Taken together with the epidemiological and environmental findings from TPH’s investigation, local public health officials are confident that the cooling tower was the source of the outbreak,” Dr. Shima Shakory, associate medical officer of health, said in a statement.
Officials also identified a possible epidemiological link between this outbreak and five legionnaires’ disease cases at Castleview Wychwood Towers, a long-term care home in the area.
They said the TTC has worked closely with them and the affected cooling equipment was shut down.
Stuart Green, a spokesperson for the transit agency, said four of its employees were among the legionnaires’ disease cases.
“We immediately took steps to identify and mitigate risk in potential sources,” he wrote in a statement Tuesday.
“This included shutting down cooling systems in two buildings that were identified as having legionella bacteria present. Further, we brought in a contractor to conduct testing and assist in the process of deep cleaning the two systems.”
The disease is caused by legionella bacteria that exists in water sources and can also be found in hot tubs, sprinkler systems, humidifiers and decorative fountains.
People can contract the disease by breathing in small droplets of water containing the bacteria.
Officials have said legionnaires’ disease does not spread from person to person and the risk to the public remains low.
This report by The Canadian Press was first published Aug. 25, 2026.
Maan Alhmidi, The Canadian Press
