What to know
- Toronto Public Health identified a cooling tower at the TTC’s Hillcrest Complex as the source of the six-person Legionnaires’ disease outbreak near Bathurst and Dupont Streets.
- The outbreak involved six confirmed cases, including four TTC employees. No one died, and TPH says the risk to the general public remains low.
- The affected cooling tower was taken offline for testing, deep cleaning and remediation. Two other TTC cooling towers were also tested and disinfected, with no Legionella detected.
- Industrial hygienist Tom Peter said regular inspection, testing and cleaning of cooling towers can help prevent Legionella from growing in conditions involving warm water, debris, scaling and biofilm.
- The TTC launched an internal review and says it has strengthened maintenance and cleaning protocols for its cooling towers beyond recommended standards.
The Toronto Transit Commission (TTC) Hillcrest Complex-based cooling tower is behind an outbreak of Legionnaires’ disease in the city’s west end.
Following an investigation by Toronto Public Health (TPH) officials, looking into the source of the six-person spread in the Bathurst and Dupont Streets area, the government agency announced the illness was contracted through water particles coming from the transit organization’s cooling tower.
TPH confirmed during the initial investigation that Legionnaires’ disease can only be spread through breathing in contaminated, aerosolized water droplets.
Read More
Legionnaires’ disease is a form of pneumonia caused by Legionella bacteria. The recent outbreak involved six confirmed cases in people who lived, worked or visited within one kilometre of Bathurst Street and Dupont Street in early July.
The TTC confirmed that four of the cases were its employees.
The tower identified has since been offline for repairs, and additional testing continues.
The TTC said it was told of the first two confirmed employee cases in late July.
“We immediately took steps to identify and mitigate risk in potential sources,” the TTC stated.
The transit agency said it shut down cooling systems in two buildings and brought in a contractor to conduct testing and assist with deep cleaning of the two systems.
The TTC said it has been working with TPH throughout the outbreak’s investigation.
“We will continue to assist in that investigation in any way that is asked of us,” they said.
TPH said environmental testing linked the tower to the Legionella strain found through a clinical sample.
The affected tower has been taken offline, and remediation has been carried out.
The TTC added that two other cooling towers were also tested out of an abundance of caution and disinfected this month. No traces of Legionella bacteria or other issues were found.
The TTC is waiting for approval from TPH before bringing the affected unit back into service, after additional testing is complete.
The focus now shifts toward making sure the bacteria has been eliminated. Additionally, the TPH will determine how the infection was able to grow in the water system in the first place.
Tom Peter is a certified industrial hygienist and senior vice president of facility hygiene and regulatory business at First On Site Property Restoration. He told Now Toronto that the outbreak displays the importance of regular maintenance in buildings.
“It really comes down to maintenance and preventive maintenance, and it’s pretty easy to treat these systems,” Peter said.
He said cooling towers should be regularly inspected, treated and cleaned to help prevent the growth of Legionella bacteria.
“That’s where the focus should be on: having a routine schedule for somebody to inspect, somebody to treat and clean on a regular basis,” he said.
He said conditions including debris, organic material, scaling, and warm temperatures can create an environment where the bacteria can grow.
“Typically, it’s associated with a biofilm or some sort of slime. Then the Legionella can easily grow with those conditions,” Peter explained.
An internal review alongside the public health investigation was launched by the TTC. The agency said they were taking the circumstance seriously.
“Safety is our top priority, and we take our responsibilities to our neighbours seriously,” the TTC said. “In parallel with the TPH investigation, we have launched an internal review to determine how our system could become a source for this outbreak.”
Peter said the response taken by the TTC in this case — including shutting down the system, testing and cleaning — is an important part of contamination control.
“In this case, especially in this Toronto case, where they took immediate action by shutting down the system to prevent the additional droplets or misting going on, and then they took action by testing and as well as cleaning immediately,” he said.
The TTC added that it has already strengthened its maintenance.
“We have already enhanced the maintenance and cleaning protocols on our three cooling towers such that they exceed recommended standards,” the TTC said. “If there are further steps that need to be taken to mitigate future risk to our employees and the community, they will be taken.”
However, Peter said the fact that similar incidents continue to make headlines shows there is still more that can be done.
“If we keep seeing these stories hit the headlines, and we see this almost every year, [facilities are obviously not doing enough],” Peter said.
For facility managers, Peter said regular inspection, testing and cleaning should be a priority.
“It should be inspection and testing and cleaning. They should have a cleaning schedule automatically,” he said.
He added that buildings at risk should have a preventative maintenance program in place.
“They should really follow and develop a preventative maintenance program in each building that’s at risk, with cooling towers or water sources that can generate Legionella,” Peter said.
No one died during July’s outbreak, with TPH saying the risk to the general public remains low.
The TTC says it will continue working with TPH, taking any additional measures necessary, to ensure the outbreak is contained and the affected system can safely get back in service.
