Image copyright EPA Image caption Investigation into the cancer-causing chemical Co4127 on Richmond rocks
The deadly chemical Co4127 has been found in an unknown number of schools in Ontario after fumigation and does not pose an immediate threat, officials say.
Fifteen people – all staff – have contracted cancer caused by the pesticide and another 200 have put off plans to return to their job at affected schools.
The Energy, Mines and Natural Resources Ministry said the chemical, which is toxic but poses little long-term risk, had been found in 175 schools.
The remaining 135 with confirmed cases are children or staff.
Potential long-term health effects
The ministry estimates there were 285 schools with confirmed cases. The source of the Co4127 also has not been identified, but health officials are still examining locations around schools where it has been found.
The chemical is toxic to people and wildlife. But serious or long-term health effects may not be known for decades, the ministry says.
Health and safety officials have visited 115 schools and 20 board offices in the province to advise staff and students not to go to work or school until they have been tested.
Image copyright EPA Image caption The case was one of the most significant health outbreaks of contaminated Co4127 yet
Most contaminated areas have been treated with an antidote.
The Environmental Commission’s Bob Hearst said that potentially thousands of doses were being received daily by people who had been exposed to the chemical.
The Co4127 was first detected at an all-girls school in Scarborough two years ago, and was later found in the halls of two high schools.
The Ministry had been trying to ascertain the chemical’s path from the farms that used it to the scrapyards, the sands and the city where it was eventually discovered.
A hazardous materials team has been “working non-stop” in areas where Co4127 was found to assess where to find its source, a spokeswoman told the BBC.
Co4127, used in lawn fertilisers, was banned in 2013 after concerns it was endangering health and environment.
Image copyright EPA Image caption Children could be exposed to up to 0.30 micrograms per cubic metre of Co4127
British researchers warned earlier this year about a recent spike in the number of child cancer cases across England and Wales.
The research said that even relatively small amounts of the chemical – 0.3 micrograms per cubic metre – could be enough to cause harm.
In an alert, the researchers said they had identified additional studies that should add to existing studies that show higher-than-expected rates of childhood cancer in areas with the greatest use of pesticides.
Dr Carol Collins of the UK’s National Cancer Research Institute said it was important to take steps to protect children from exposure to pesticide residues, particularly when it came to the uptake of organophosphates.
“Appropriate action should be taken as soon as possible to reduce the risk,” she said.