With spring barely upon us, a favourite Winnipeg summertime debate has already flared up.

A recent report by the World Health Organization links the city’s preferred mosquito-killing chemical with certain types of cancer.

The report by WHO’s International Research Agency for Cancer says malathion could contribute to non-Hodgkin lymphoma and prostate cancer.

"We've known all along that malathion is harmful and this is simply another indication of mounting evidence that malathion hurts people,” said Dave Nickarz who led the charge in the early 2000’s against the controversial practice of mosquito fogging, even getting arrested during a protest.

"If they decide to go fogging this summer, they're going to be using a likely carcinogen that's damaging people's health,” he added.

In a statement to CTV News, the city said the report will be looked at before this year’s mosquito season.

“The City of Winnipeg Public Service will be reviewing the WHO report in consultation with Health Canada who license and regulate the use of malathion by municipalities,” said the city.

Entomologist Taz Stuart, now of Poulin’s Pest Control, oversaw the mosquito-control program in Winnipeg for a decade and was responsible for determining when to spray malathion.

"Health Canada, the pest management regulatory agency, deemed the product safe when you're applying it according to label directions,” said Stuart.

According to Stuart, Winnipeg is the only major city in Canada that still uses malathion.