Mould a health risk in the metro

Mould growing inside Montreal metro stations could pose a health risk to workers who spend long periods of time in the underground tunnels, according to a government health official.
While mould doesn’t usually grow on the types of materials found in subway stations, such as tiles and cement, certain metro stations have become increasingly linked with the potential sanitary hazard, caused by water infiltration and dirt. The problem is particularly visible at Berri-UQAM, where grey mould can be seen spreading near exposed pipes, small water leaks, walls and ceilings.
Doctor Norman King, an epidemiologist at Agence de la santé et des services publiques de Montréal, says that while the mould isn’t a danger to passerby, it could become a potential health risk for people who are exposed on a long-term basis.
“If someone had to work in an area like that [an extremely mouldy tunnel] eight hours a day, five days a week, for weeks and months, that person could develop respiratory symptoms,” he said.
Concordia University associate professor of geography, planning and the environment Judith Patterson explains that the strong gusts of air caused by the movement of the metro cars could potentially disperse the mould, leading to an increase in symptoms for people who already suffer from respiratory problems.
Still, “there is no health risk for people who are just passing through on their way to the metro,” King said.
“If you were to walk through a very mouldy tunnel, [ . . . ] you could have eye, nose and throat irritation. [ . . . ] But if you get out into fresher air, then the symptoms will disappear. They won’t have a long-term effect.”
According to a 2002 report compiled by the Institut National de Santé Publique du Québec, exposure to mould in an inside environment has been linked to irritation of the eyes, nose and throat, rashes, respiratory difficulties and the exacerbation of asthma. Other recent studies have also suggested the toxic effects of mould may cause irritability, headaches and fever. However further research is needed to corroborate these findings.
While King doubts the problem in the metro system will get out of hand and become a health hazard for commuters, he says the same situation would be problematic in an office or school setting. “If that would have [occurred] in a school, it would be a public health concern. If we were made aware of it, we would issue recommendations for that situation to be corrected,” he said.
King adds that people often ask the health agency whether the mould they find in their homes or offices should be tested, but that there’s no point in determining what type of mould it is. “Once you see mould growing on building materials, it’s not a normal situation,” he said. “Once it’s there you have to get rid of the problem that caused it in the first place. If you clean up the mould and leave the water infiltration, the problem is going to come back.”
Société de transport de Montréal (STM) spokesperson Nadine Cordier refused to comment on the situation unless a list of questions was sent prior to the interview. However, according to the STM’s 2007-2011 business plan, improving cleanliness in the metro is the company’s 11th goal in their list of 33 top priorities.