Marijuana tourism is forecast to inject up to $2 billion a year into Canada’s economy once the recreational drug becomes legal throughout the country on October 17 of this year.

Shaman Ferraro, Chief Executive Officer of cannabis tourism guide Gocanna, predicts that Canada will see a major boost in tourism revenue once marijuana and cannabis become legal — with pot tourism eventually contributing $2 billion a year to the country’s national economy.

Ferraro has based his forecasts on a report that Colorado’s tourism agency commissioned in 2015, which found that 4% of the state’s tourists visited solely to acquire access to legal marijuana dispensaries, and 23% said access to cannabis influenced their decision to visit the Rocky Mountain state. It’s also based on Statistics Canada data on how much US tourists spend while traveling through Canada.

“The tourism sector is going to be huge for cannabis,” said Ferraro, who spoke to Canadian television news channel BNN Bloomberg at the Marijuana Business conference held last week. “There’s going to be some early adopters but as the industry evolves, you’re likely to see more integration of cannabis in tourism hot spots.”

He cautioned though that it will take some time for the marijuana tourism sector to grow and reach $2 billion in annual revenues. He noted that the burgeoning industry is only now figuring out how to effectively market marijuana to tourists.

The ways in which businesses can publicly promote marijuana and cannabis will be an issue for tourism operators as there are tough government restrictions in the federal legislation that legalizes the drug. The legislation that’s been passed in Canada’s Parliament consists of regulations on how marijuana and cannabis can be marketed, prohibiting company sponsorship, contests, and endorsements by celebrities.

Businesses that violate the marketing restrictions placed on marijuana and cannabis products will be subjected to licence suspensions, fines as high as $5 million, and/or jail time, according to Health Canada, which is overseeing the Canadian government’s legalization efforts.