Canada’s medical cannabis industry is making a push in the Senate to ban large-scale outdoor cannabis cultivation.

Allan Rewak, the executive director of the Cannabis Canada Council, an industry association that represents licensed producers of medical marijuana, urged senators Wednesday to prohibit large-scale outdoor cultivation in the government’s pot legalization legislation.

He said allowing it presents a “heightened degree of risk for diversion into the illegal market place.” It also raises concerns about the dangers of unintentional exposure to agricultural pesticides and cross-pollination.

Bruce Linton, the head of Canopy Growth Corp., agreed. He said outdoor cultivation “may have a future sometime, but I don’t think it’s today.”

He added it “sidesteps all the benefits” of the current supply chain system.

Under a current Health Canada regulatory proposal, the Liberal government’s cannabis legalization framework would allow licensed pot producers to grow cannabis outdoors. Currently, commercial outdoor production is not allowed.

Earlier this month, New Brunswick’s Health Minister Benoît Bourque made a similar plea to the same Senate committee studying Bill C-45. He shared the same concerns as producers, but also argued that allowing indoor growing could level the economic playing field across Canada.

“We think that indoor cultivation will allow all regions of Canada, including New Brunswick, to benefit from investments in cannabis production facilities,” Bourque told senators studying the legislation. “That way, the benefits will not be limited to regions with a climate that makes outdoor production viable.”

But others have previously made the push for the government to open up outdoor pot cultivation to reduce the carbon footprint of growing weed indoors.

In April, Jonathan Page, a UBC professor and CEO of the cannabis company Anandia Labs, told senators indoor growing creates “significant power needs.”

“There are significant environmental costs to indoor production, including electricity usage,” he said. “Outdoor production can mitigate some of these problems and should be considered an option.”

“For larger commercial production, I’m sure that Health Canada will mandate sufficient security requirements to protect outdoor crops from theft and diversion.”

The federal government’s consulting task force had recommended Ottawa should allow for outdoor commercial growing with “adequate security requirements” in order to “limit the environmental impact of the cannabis industry.”

Eric Costen, the director general of Health Canada’s Cannabis Legalization and Regulation Secretariat, said in March the government has been giving “close consideration” to the issue and how it would “minimize the risks” of diversion and other problems, while “at the same time allowing for the benefits of outdoor cultivation.”

“There are a number of regulatory safeguards, such as perimeter fencing for large-scale growers, video surveillance activities… intrusion detection systems,” he said during a media teleconference when the regulations were announced.

The government wants to legalize cannabis this summer. The medical cannabis producers who testified Wednesday, unsurprisingly, said the bill is “good public policy” and should be moved through the Senate “as quickly as reasonably possible.”