Two men from Quebec are facing criminal charges following a raid on a licensed medical cannabis grow operation in an agricultural area north of Toronto.

York regional police say officers seized nearly 290 kilograms of harvested cannabis and more than 4,000 plants in King Township, Ontario, late last month.

Police are working to identify production licence holders growing excessive amounts of cannabis under Health Canada authorizations.

Police say the large-scale cannabis grow operation was discovered on July 26 while officers were helping with a safety inspection of the property, which has 22 greenhouses.

Investigators say there were three Health Canada licences in place that allowed a total of 875 plants to be grown for medical purposes.

Officers returned on July 27 with a search warrant and removed cannabis plants in excess of those allowed by the licences.

Two men who were maintaining the plants—a 36-year-old from Montreal and a 43-year-old from Laval, Quebec—are charged with possession of marijuana for the purpose of trafficking and producing marijuana.

“This criminal enterprise was operating well in excess of Health Canada authorizations to grow cannabis for medical purposes,” Chief Eric Jolliffe said Friday.

Investigators allege that the cannabis was being grown in an unregulated, illegal, and unsafe manner, with no quality control, environmental considerations, or security measures.

Jolliffe said police are working to identify personal and designated production licence holders that are growing excessive amounts of cannabis under Health Canada authorizations.

“The product is then diverted to the illicit market by organized crime groups to supply illegal dispensaries, export outside of Canada and trafficked in our local communities,” he said.

Police say the investigation is ongoing.