The province launched a lawsuit against a group of 14 Canadian, American and British-based tobacco companies in 2009 to help recover costs of treating people with smoking-related illnesses.
The tobacco companies argued the province did not have the jurisdiction to sue them, but this week the Ontario Superior Court of Justice dismissed their objections, so the lawsuit can proceed.
Ontario's statement of claim alleges the tobacco companies knew about the addictiveness of cigarettes and the health damages they caused, and deceived the public by misrepresenting the risks.
The province also claims the tobacco companies promoted cigarettes to children and teens and failed to warn the public about the dangers of smoking.
The claims have not been proven in court.
Rob Cunningham, a lawyer for the Canadian Cancer Society, applauded the court decision Friday.
"It's a big win for the Ontario government," he said. "It's a big defeat for the tobacco industry."
"This judgment by the Ontario court is very similar to earlier judgments by the courts in British Columbia and New Brunswick on the same issue.
"In some of the other provincial cases, the foreign parent companies tried to be removed as defendants but were unsuccessful and now they've been unsuccessful in Canada's biggest province."
The Ontario government says smoking costs the province's health-care system $1.6 billion each year, and is the number one cause of premature death and illness in the province.
The province passed legislation in 2009, the Tobacco Damages and Health Care Costs Recovery Act, to allow the government to sue for recovery of past, present and continuing tobacco-related damages.
It also created a method to determine the costs associated with tobacco-related illnesses and allocated liability by market share.
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