Ottawa's public health agency believes the minimum age for buying legal marijuana should be set at 25, according to a submission it sent to the federal task force examining what legalization will look like in Canada.

The submission, sent earlier this summer and to be tabled before the Ottawa Board of Health on Oct. 17, includes some 33 recommendations on minimizing harm, establishing a safe way to produce and distribute marijuana, accessing marijuana for medical purposes and ensuring public safety.

Setting a minimum age for the drug was one of the most discussed issues among the 28 health agencies working together to share ideas on the issue, according to Gillian Connelly, manager of Health Promotion and Disease Prevention with OPH.

"We wanted to ensure that we're reducing access for youth," explained Connelly.

"One of the things that the research clearly demonstrates is that early access to cannabis can have detrimental affects for brain development and the brain develops up to age 25."

OPH also suggests the minimum should be Canada-wide and "must be coupled with rigorous enforcement and penalties for violations in order to be effective."

No consensus on minimum age for marijuana use

The minimum age of 25 is in line with recommendations offered up already by the Canadian Medical Association, but there was no consensus among health agencies, according to Connelly.

Some agencies thought not having alignment between the minimum drinking age and marijuana may be unrealistic, and difficult to enforce, but Connelly said OPH wanted to signal to the federal government a recommendation rooted in science research at this stage of the process.

"We'll have another kick at the can," said Connelly, "and should the federal government come up with a different recommendation in the spring, we'll reassess."

But Bruce Linton, the founder and CEO of Tweed, one of the largest medical marijuana producers in the country, said there could be perverse consequences to setting the minimum age too high.

"Every market which is not available for the legal organized suppliers is a market available for the other guys," said Linton.

"Because to believe that the people who wish to buy this product aren't going to get it I think doesn't recognize where we are already with the market," said Linton who thinks the minimum age should match the drinking age of 19 "to be consistent."

Other recommendations include:

Prohibit advertising, marketing and sponsorship and employ plain packaging similar to legislation being considered for tobacco.

Adopt a government-owned and controlled storefront system for distribution.

Ban consumption of marijuana in workplaces and indoor and outdoor public spaces.

Regulate base pricing based on THC content — the drug that gives marijuana its potency.

Utilize controls on edible products, including child-proof packaging.

OPH is recommending a portion of revenues from cannabis go toward more research, to help fill the "many gaps in knowledge" as well as supporting investments in education and prevention particularly toward adolescents, as well as those with "a personal or family history of mental illness."