B.C. marijuana advocates have officially rolled out their campaign to effectively decriminalize pot possession.

Sensible BC has three months to collect signatures from 10 per cent of the province’s registered voters in all 85 ridings.

If they succeed, the petition would force the province to hold a referendum on marijuana laws, or force a vote in the legislature.

“No one’s ever tried a referendum campaign like this before,” Sensible BC spokesman Dana Larsen said Monday, as he and canvassers collected signatures in downtown Vancouver.

“I’ve been working on this campaign for 20 years,” he said. “It was a lonely road sometimes.”

It’s not lonely anymore – Larsen said 1,500 people are already signed up to help out with the 90-day campaign, and expects more will volunteer along the way.

He balked at the suggestion that gathering signatures in conservative rural areas of B.C. like Abbotsford and Chilliwack will be the campaign’s biggest challenge.

“I had standing room only events in both of those towns,” he said. “I’ve spent so much time travelling through those areas and finding local canvassers that, we have a lot of support.”

Larsen said he’s more concerned about garnering enough signatures in places like Vancouver and Surrey, because those cities’ population densities mean canvassers will need to collect an exponentially larger amount of signatures.

Vancouver resident Eileen Curtis said she supported the campaign because she had cancer three years ago and had a bad reaction to chemotherapy treatment.

“I was completely allergic to it,” she said. “[Pot] worked like a charm…It sure as heck helped me, so I’m all for it.”

Another Vancouver resident told CTV News she wouldn’t be signing the petition.

“For me, it makes no sense whatsoever,” she said. “This is such a beautiful city, why on earth do you have to smoke something to feel better about it?”

The only other time such a campaign has succeeded was in 2010 – when B.C. voted to end the Harmonized Sales Tax.

Volunteers from that campaign have joined up with the Sensible BC campaign, Larsen said.

The push for decriminalization has also gained steam with several prominent former politicians, including former Liberal attorney general Geoff Plant and former NDP premier Ujjal Dosanjh, calling for the legalization and regulation of marijuana.

Their group, the Stop The Violence B.C. Coalition, has pointed to opinion polls that suggest a majority of British Columbians agree with them.

Larsen has said he’s confident that if his petition collects enough signatures, a referendum would result in a resounding victory.

Towns across the province can expect to see the Sensible BC crew roll up in the “Cannabus,” a converted Greyhound bus that doubles as a mobile sign-up station.

With files from CTV British Columbia’s St. John Alexander and The Canadian Press