A legal marijuana grow operation in Maple Ridge, B.C., has been given a warning by the city to address concerns or risk being shut down.

Neighbours of the Kingston St. grow operation, housed in an industrial building, say it’s the source of a serious problem: wafts of pot so strong it’s giving people headaches.

Herb Hanna says it’s so pervasive it overpowers the aroma of coffee roasting at his business.

"I roast coffee, the company beside me roasts coffee, but the funny thing is it was always smelling (like) marijuana,” he told CTV News, adding that it’s driven customers away.

Maple Ridge Mayor Ernie Daykin says they've had so many complaints they're giving the grower 30 days to comply or risk being shut down.

Daykin believes the building isn’t vented properly and is missing a number of filters.

"They need to have it inspected, bring it up to electrical and all of the building code standards and that include the filtering and noxious odours and all that stuff,” he said.

Daykin feels the problem is widespread, with many other B.C. cities dealing with the complications that come with the vague legalities around grow operations.

“You could go to 12 or 22 other municipalities in Metro Vancouver and have similar experience,” he said.

Marijuana activist Dana Larsen said that grow-op safety should be the top concern, not smell.

“That’s not a serious issue,” he said. “The smell of marijuana is not dangerous or harmful.”

Despite his criticism, Larsen does believe all growers should try to be good neighbours.

"I would try to make a better effort and it's certainly not that difficult to vent those smells, to use different things to screen the smell out,” he said.

The question of grow safety came into prominence earlier this week, when an overnight fire leveled a Maple Ridge home that contained a grow operation.

And a legal medicinal grow-op in Port Coquitlam was shut down in February after the operator was found growing triple the plants he was licensed to have, in addition to safety, noise and smell complaints.

Last fall, the federal government announced it intends to make changes to the way Canadians access medical marijuana.

The proposed new ‘Marihuana for Medical Purposes Regulations’ will eliminate home grow operations and move production to commercial growers.

Under the new rules, to be finalized by March 2014, anyone who requires medical marijuana would have to buy it from licensed producers.