In testimony to a Senate committee in Ottawa, Michael Bourque, head of the Canadian Real Estate Association, flagged risks associated with cultivating cannabis plants, such as the spread of mold and fungus through ventilation systems. He said the law should be amended to place a moratorium on home cultivation until provinces can pass tougher housing regulations.

The home-safety argument may set up another hurdle for Prime Minister Justin Trudeau, who is seeking to pass the marijuana bill in the next few months so the market can open for business later this year. Trudeau’s Liberal government says legalization will squeeze out criminal producers and help bring down high rates of youth consumption.

Although the law would allow people to grow up to four plants at home, Bourque, who represents 125,000 real estate brokers, said there’s no limit on plant size, meaning growers could raise giant plants that produce 5 kilograms (11 pounds) of grass a year, increasing the risk to homes and health.

“We question if personal cultivation is even necessary” when there is a “well-funded, well-capitalized industry,” Bourque said Monday. “The legislation ignores evidence that growing cannabis indoors can be hazardous to the home, and health of home owners.”

As Bourque was giving his testimony, the Royal Canadian Mounted Police said they arrested a New Brunswick man after a call to a house fire resulted in the seizure of 485 marijuana plants.