A provincial New Democrat says former officials with the Ontario Ministry of Transportation have told him that Agent Orange was sprayed near highways across the province until the 1980s.

Gilles Bisson, the member for Timmins-James Bay, said during question period at Queen's Park in Toronto that an email sent to him by the officials indicates the substance was sprayed along the side of the highways to curb the growth of grass and shrubs.

"It would appear that there was a good chance that if you were an employee, you were exposed," said Bisson. "And if you were the travelling public walking along the roads — blueberry picking, doing whatever — you might have been exposed to these chemicals."

Ken Graham was a highways supervisor in Cochrane, north of Timmins, Ont., in the late 1970s.

"We would drive along the shoulders of the highway, and spray out there," he told the CBC.

Graham said he and his co-workers wore no protective respirators.

Ontario Transportation Minister Kathleen Wynne acknowledged in the legislature that "questions are being asked" about the role of her ministry regarding the use of Agent Orange. Wynne said she had only been briefed about the matter Thursday morning, and that she doesn't have the details yet.

The governing Liberals launched a probe last week into the province's use of Agent Orange after former workers came forward saying they'd been exposed to it.

Archive documents also confirmed that forestry workers were exposed to toxic herbicides while helping to clear massive plots of Crown land in northern Ontario in the 1950s, 1960s and 1970s.

Wynne said after question period that she was "concerned" when she first heard about the news.

"I did not have any information about how the herbicide had been used in the [Ministry of Transportation]. We're just asking those questions now. And we're going to work closely with [the Ministry of Transportation] to make sure we get A, the right questions asked and B, the answers," she said.

Agent Orange, a defoliant best known for its use during the war in Vietnam, has been linked to birth defects and deadly illnesses. Its use was banned by the federal government in 1985.

The only documented case of Agent Orange use in Canada occurred at CFB Gagetown in New Brunswick during the 1960s.

The federal government compensated thousands of people who lived or worked near the base at the time. Those compensated were diagnosed with one of 12 medical conditions linked to Agent Orange exposure.

Graham said he plans to get tested by doctors to find out if there is any trace of the chemical in his body.

"If I've got that in my system, somebody is going to have to pay some compensation somewhere along the line," he told CBC News.

He is also talking to his former colleagues about the possibility of a class-action lawsuit.

With files from The Canadian Press