A company that makes the commonly used herbicide ingredient 2,4-D is challenging the Quebec government under the North American Free Trade Agreement for banning its product.

The Canadian unit of Dow AgroSciences alleges the prohibition of the weed killer is without any scientific basis and in violation of the trade agreement between Canada, the United States and Mexico.

"We are of the view that this is in breach to certain provisions of NAFTA," Jim Wispinski, president and CEO of Dow AgroSciences, said in a press release. "We don't welcome this step but feel it is necessary given the circumstances."

Wispinski called the province's prohibition "tantamount to a blanket ban based on non-scientific criteria." He argues public policy decisions should be based on scientific evidence and a clear set of rules.

The company is challenging the province under Chapter 11 of the free trade agreement, which includes a provision that allows private companies to sue the federal governments of any of the three countries if a member country enacts laws that "expropriate" their profits.

On April 3, 2006, Quebec brought in a sweeping pesticide ban, pulling more than 200 products from provincial shelves.

In a statement of intent made public on Wednesday, Dow AgroSciences argues the province suggested a review of the herbicide by Canada's regulatory agency might influence its consideration of the ban but despite its favourable finding it did not.

The Health Canada Pest Management Regulatory Agency concluded earlier this year that 2,4-D meets its health and safety standards if used according to the label's directions, the statement notes.

Pesticide use on lawns has become controversial in recent years because of the potential impact on the environment and human health.

In June, Ontario passed legislation that will ban more than 80 ingredients and 300 pesticide products once the law is fully implemented next spring. The Ontario law, however, stopped short of banning 2,4-D or 2,4-Dichlorophenoxyacetic acid.

With files from the Canadian Press