Diamond & Diamond, a national personal injury law firm in Canada, is spearheading a $500 million class-action lawsuit against various Roundup makers, including pharmaceutical company Bayer, the owner of Roundup maker Monsanto.

Roundup is a weedkiller that contains glyphosate, a herbicide chemical often used by homeowners to treat their lawns.

There have been many lawsuits filed across North America alleging that glyphosate can cause health problems including non-Hodgkin's lymphoma, a type of cancer that affects the lymphatic system.

In the United States alone, there have been about 18,000 lawsuits filed against the makers of Roundup.

Diamond & Diamond is calling this Canada's largest class-action lawsuit against Roundup makers. There are currently more than 60 individuals named as plaintiffs, but the firm said they believe thousands may have been affected.

This year, there have already been lawsuits against Roundup manufacturers filed in B.C., Quebec, Saskatchewan and Manitoba. This one would be the first class action in Canada and follows the likes of class-action lawsuits filed in the U.S.

Darryl Singer, the head of commercial and civil litigation at Diamond & Diamond, said the plaintiffs involved in this class-action lawsuit are looking not only for financial compensation, but also what he calls "behaviour modification" so that the same thing doesn't happen again in the future with other products in Canada.

"If there's not these lawsuits that force companies like Monsanto to write these big cheques, they have no incentive to change the way they do business," Singer said.

Singer said the plaintiffs have also been diagnosed with other forms of cancer, like brain and lung cancer, and some of his clients are acting on behalf of an estate.

"These are not minor injuries," he said. "Of the [plaintiffs] that are living, some of them are not likely to see the end of this lawsuit because they will pass away before that."

Bayer Canada said it will "vigorously defend" its products, according to a statement the company provided to CBC News.

"While we have great sympathy for the plaintiffs, glyphosate-based herbicides are not the cause of their illnesses," the statement said.

"Glyphosate has been extensively studied globally by scientists and regulators, and results from this research confirm it is not carcinogenic. We firmly stand behind the safety of glyphosate-based products and as a company devoted to life sciences, assure Canadians that their health and the environment are our top priority."