TORONTO - The burning question about precisely where a person can smoke these days is flaring up again in Ontario, where a 48-year-old trucker faces a $305 fine for lighting up on the job: while driving his big rig along Canada's busiest highway.

The man, who hails from London, Ont., a two-hour drive southwest of Toronto, was headed for the Ontario border city of Windsor when he was pulled over Wednesday along Highway 401 and given a ticket under the Smoke-Free Ontario Act.

The law, considered a Canadian standard-setter when it was passed in 2006, forbids smoking in all workplaces and enclosed public spaces, including buildings, structures or vehicles worked in or frequented by employees, according to the government's website.

"Examples of an enclosed workplace include the inside of a trailer office on a construction site, the inside of a loading dock, or the inside of a delivery truck," the site says.

Ontario provincial police Const. Shawna Coulter said the law is very explicit about what constitutes a workplace.

"It says the inside of any place, building, structure or vehicle that is part of the employee's workplace, which if you're driving a truck for long periods of time -- that becomes your workplace."

The driver, whose name was not immediately released, could have good reason to fight the ticket in court, said Doug Switzer, vice-president of the Ontario Trucking Association.

The provincial law ought not apply in the case of federally regulated trucking companies that operate in other provinces or the United States, Switzer said -- nor should it be brought to bear on truckers who own and operate their own rigs and work alone.

"It is a little complicated on the enforcement end because you've got thousands of people from OPP, municipal police forces and health unit enforcement staff, not all of whom are versed in the subtle nuances of the trucking industry or the smoking legislation," Switzer said.

Julie Rosenberg, a spokeswoman for Ontario's Ministry of Health Promotion, refused to comment Thursday on whether or not the law would be applicable in the case of a truck belonging to a federally regulated company.

In the event the driver of the truck did not construe an employee as defined by the legislation, however, "the vehicle in question would not meet the definition of an enclosed workplace," Rosenberg said in an email.

Transportation Minister Jim Bradley said he'd never heard of such a case, and while he couldn't comment on any particular case, said he'll be watching to see how this one unfolds.

"It would be interesting to see how this develops," Bradley said. "That's interesting. It's a new one to me."

Coulter said it was unclear whether the fine was the first of its kind in Ontario. "We don't track specific charges, but I don't know that it's been utilized in the past," she said.

Nonetheless, that's the way the law is supposed to work, said Health Promotion Minister Margarett Best.

"It's about health, and I'm not looking at this from the perspective of whether it's a milestone or not," Best said of the charge. "I'm looking at it from the perspective of being concerned about the health of Ontarians."

Neil MacKenzie, the manager of tobacco programs for the Windsor-Essex County Health Unit, said even a farmer's enclosed tractor would be considered a work environment.

"Whether or not you have the sunroof open or windows down ... it's an enclosed workplace and you're prohibited from smoking in that vehicle," MacKenzie told Windsor radio station CKLW.

Still, no one would march into a field and fine a farmer for smoking in an enclosed tractor, he said.

"Before we take any radical action on it, we'd confirm with the Ministry of Health whether there's precedent," MacKenzie said.

"We'd make sure the farmer understood requirements and give the opportunity for full compliance."

Ontario's Liberal government, first elected in 2003, has been aggressive in its efforts to curb tobacco use in the province. Last summer, the province amended the Highway Traffic Act to prohibit smoking in cars carrying children.

Stringent anti-tobacco laws prohibiting smoking in covered public places and workplaces, like restaurants and bars, are also in effect in a number of other Canadian provinces and territories, including Manitoba, Saskatchewan, Quebec, the Maritime provinces, the Northwest Territories and Nunavut.

Last February, a 29-year-old woman from the Sarnia, Ont., area was charged under the ban after she was allegedly found smoking with five young children in the vehicle. Officers said they found both the driver and a 19-year-old female passenger smoking cigarettes.

John Tuckwell, spokesman for Alberta's Health Ministry says technically a trucker could be fined in his province.

Under Alberta legislation, the cab of truck is considered a workplace if the driver is not alone in the rig, says Tuckwell.

But he's not aware of any charges being laid under these circumstances.

Several provinces, meanwhile, plan to join forces against tobacco companies to recover health-care costs related to smoking.

Quebec confirmed earlier this month it was joining Ontario, British Columbia and New Brunswick in filing a multibillion-dollar lawsuit against tobacco manufacturers.

Ontario's $50-billion lawsuit against three tobacco companies is aimed at recovering the cost of treating smoke-related illnesses dating back as far as 1955.

The provinces began to consider legal action after a 2005 Supreme Court of Canada ruling that upheld British Columbia's right to seek compensation against tobacco companies.