OTTAWA -- The Liberal government’s plan to have marijuana legalized by July 2018 won’t wipe out the black market for some time, and could come with other unintended consequences, the committee of MPs studying the legislation heard Monday.

“It will take time. We will learn what this marketplace needs, both in terms of safety and health, but also trying to get the black market or illegal market out of this space,” Anne McLellan, the former Liberal cabinet minister who led the federal task force on marijuana told MPs.

“We’re not naïve, we’re not suggesting that you’re ever going to reach nirvana in terms of that there won’t be any illegal sales. We still have illegal sales of tobacco and a little bit of illegal sales of alcohol,” she said.

McLellan was one of nearly two dozen witnesses testifying at the House Health Committee in Ottawa Monday. The pot task force she chaired studied the issue and reported back to the government ahead of the legislation being tabled.

The committee is meeting throughout the week to get a head start on studying Bill C-45, the Cannabis Act, before Parliament resumes Sept. 18.

The bill, once passed, would allow adults in Canada to possess and use small amounts of recreational marijuana legally. It sets out the parameters around the production, possession, safety standards, distribution, and sale of marijuana. It also creates new Criminal Code offences for selling marijuana to minors. The proposed federal law spells out that it will be illegal for anyone younger than 18 to buy pot, but is leaving it up to the provinces and territories to set a higher age.

The committee of MPs is holding a marathon session of meetings, from 8:30 a.m. to 6 p.m. through to Friday. It’s scheduled to hear from dozens of witnesses over the course of these meetings.

Monday’s focus was on federal, provincial and territorial responsibilities, what the industry has to say, as well as public safety considerations.

The message a number of witnesses shared with MPs was that legalizing marijuana won’t immediately eradicate the black market for pot.

"We know that it is going to take some time to fully displace a sector that has over a century made a good gain in this area," said Kathy Thompson, assistant deputy minister in the community safety and countering crime branch of the Department of Public Safety. “It’s going to take some time and it’s going to take a robust regime,” Thompson said.

MPs heard that stamping out the illegal market will require making sure the licensed producers approved to sell legal recreational marijuana are able to compete with the black market on things like quality, price, product choice, branding, and access.

McLellan also cautioned the government to “remain vigilant and be prepared to course correct” as the process of legalization unfolds. “There will be unforeseen challenges and unintended consequences," she said.

"Only through careful and close monitoring and a willingness to be flexible and adaptable will it be possible to respond effectively to issues as they emerge," said McLellan.

Constitutionality concerns raised

Criminal lawyer Michael Spratt told the committee that Bill C-45 is “an unnecessary complex piece of legislation that leaves intact the criminalization of marijuana in too many circumstances.” For example, Spratt highlighted that under the proposed law, an 18-year-old who passes a joint to a 17-year-old friend would be breaking the law, as would an adult who lets their home-grown plant grow one centimetre taller than the law allows.

"This continued criminalization is inconsistent with a rational and evidence-based criminal justice policy and will only serve to reduce some of the positive impacts of this bill," Spratt said.

Spratt also raised concerns over the constitutionality of ticketing provisions in the bill, which give police forces the ability to issue tickets for minor violations, like possessing just over the 30-gram legal limit.

The bill says that if the ticket is paid on time, the court record would be kept private, but not if the fine is not paid. Spratt says this disadvantages the poor.

“If you are poor and can’t pay a fine you are further stigmatized through a public record,” said Spratt.

“It’s quite likely that this ticketing provision in Bill C-45 will be found to violate the Canadian Charter of Rights and Freedoms,” he said.

This argument was likely already on the government’s radar, as the provisions around ticketing were highlighted by Justice Minister Jody Wilson Raybould in the Charter statement she issued alongside Bill C-45. A Charter statement highlights the portions of any bill that could have implications on rights protected by the Charter.

Hearings continue throughout the week

Later in the day, the committee heard from marijuana industry associations and will be rounding out the first day with testimony from the Canadian Medical Association, Canada Border Services Agency, and the Vancouver Police Department.

On Tuesday, the committee will hear about the experiences Colorado and Washington had with legalizing marijuana. It will also hear from police services across Canada.

On Wednesday, the committee will hear testimony on growing marijuana plants at home, as well as have witnesses speak to legal possession age and the impact on young Canadians. There will also be a panel on prevention, treatment, and low-risk marijuana use.

On Thursday, the committee will delve into labelling and packaging, legalization and Indigenous communities, and workplace safety.

And on Friday, edible marijuana products, medical marijuana, municipalities, and international considerations will be discussed.

Bill C-45 is the first of a two-part implementation of the government’s marijuana legalization package. The second piece, Bill C-46, An Act to amend the Criminal Code (offences relating to conveyances), changes Canada’s impaired driving laws to give law enforcement new powers to conduct roadside intoxication tests, and would make it illegal to drive within two hours of being over the legal limit.

The House Justice and Human Rights Committee held its first meeting on Bill C-46 in June, where it heard from Wilson-Raybould and Department of Justice officials, and it’s expected to hold similarly concentrated meetings on the bill once Parliament resumes.