Tests sponsored by PSPC showing high legionella levels may be unreliable, says PSPC
Tom Spears
Mar 21, 2018 • Last Updated March 21, 2018 • 3 minute read
Google street view image of Environment Canada Building on 4905 Dufferin Street
Public Services and Procurement Canada doesn't accept data suggesting cooling systems in some federal buildings have high levels of legionella bacteria, saying that while the department sponsored the research, it believes the testing technology is still unproven.
This week an Ottawa company said its DNA testing, which it stands by, found unexpectedly high levels of the bacteria that can cause legionnaires' disease, a form of potentially lethal pneumonia.
The bacteria can grow in cooling towers — rooftop water tanks that absorb heat from the air conditioning systems. The potential danger is when water vapour from these tanks is drawn back into the building's ventilation through an air intake.
Spartan Biosciences of Ottawa studied federal office buildings for PSPC, and concluded that 39 per cent of the 51 cooling towers it tested last year had unacceptably high bacterial levels. It argues that sending samples away to a lab that grows a bacterial culture gives understated numbers because bacteria often die during the shipping.
But PSPC now says it is relying on its traditional testing methods, which showed lower levels. The highest levels it found that way indicated that some towers needed to be watched, but had not reached hazardous levels.
"We support innovation through this Build In Canada Innovation Program, but that test procedure is innovative. It isn't commercially available. It is meant to test the actual methodologies," said Kevin Radford, an assistant deputy minister with PSPC, referencing the program that sponsored the Spartan research.
And he said PSPC's testing methods "meet or exceed" any in North America.
PSPC was interested in Spartan's fast technology — results in 45 minutes instead of days or weeks — and commissioned the study to see how well it works.
For some buildings, the results were far from positive. Four of the 51 cooling towers tested were at least 10 times over the limit for legionella bacteria. One tower was at least 100 times over the limit.
The building with that tower was disinfected as a precaution, said Radford.
That building houses Environment Canada on Dufferin Street in Toronto, this newspaper has learned. Three other buildings that showed lower but still elevated bacteria levels haven't been identified by PSPC.
PSPC sent Spartan's report to both Health Canada and the Quebec Ministry of Health and Social Services and both said the technology needs more testing.
Radford said there are measures in the rooftops to keep water vapour from leaving the cooling tower and being pulled into air intakes, so having bacteria in the towers doesn't mean there are bacteria in the building's air.
Building workers weren't notified because bacterial levels never reached hazardous levels, he said.
Paul Lem, the CEO of Spartan, said his firm's DNA testing is superior to anything PSPC is using.
"It is well known in the industry that legionella culture is a terrible test. It has very poor performance," he said. The U.S. Centers for Disease Control and Prevention found that labs using these culture tests got results that averaged 17 times too low, he said.
"We showed in our study that all the bacteria are dying (on the way to the lab) 60 per cent of the time," he said.
Lem said the PSPC trials produced fresh evidence supporting his own company's testing. In some cases they did conventional culture tests in a Petri dish right at the scene, to get around the problem of shipping samples to a lab. And these on-the-spot culture tests and the DNA tests showed the same results, he said.
"We are talking about people's lives. Every day, people are going to office buildings, shopping malls, schools, and hospitals and they are at risk of contracting legionnaires' disease from contaminated cooling towers. The good news is that the risk is preventable, and the solution is easy to use and affordable," he said.
In the capital, the buildings tested were: the John Diefenbaker Centre at 111 Sussex Drive; Natural Resources at 580 and 588 Booth Street; the Canadian Police College residence at 1 Sandridge Rd.; the heating plant for the RCMP on Vanier Parkway; Centre de Préservation de Gatineau at 625 du Carrefour; Place du Centre in Gatineau; all four phases of Place du Portage; a heating plant at 45 Sacré-Coeur in Gatineau; Asticou in Gatineau; 22 Eddy Street and 30 Victoria Street in Gatineau; the heating plant for Les Terrasses de la Chaudière; seven cooling towers on National Defence's Carling Campus at 3500 Carling; the National Defence Data Centre at Tunney's Pasture. Other buildings were in Toronto and Montreal.
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