Ontario Provincial Police have charged 12 people from Ontario and Quebec in connection with a massive marijuana grow-op bust in a former Molson brewery near Barrie, Ont., six years ago.

Police announced at a news conference Thursday that the people have been charged with drug and criminal enterprise offences.

Officers seized property and vehicles worth more than $7.5 million under proceeds of crime legislation.

The property includes the former brewery building, a property in Elliot Lake, Ont., vehicles and cash.

Police swarmed the former brewery in January 2004 and seized 30,000 marijuana plants, which had a street value of millions of dollars.

Police said the growers used more than 5,574 square metres in the operation. They also had living accommodations for up to 50 people, including common areas, televisions, refrigerators and stoves.

At the time, the grow-op discovery was called the largest and most sophisticated marijuana operation in Canadian history, police said.

Nine people who lived in the plant were arrested in 2004. Police had said millions of dollars were invested in equipment for the operation, which was capable of producing up to three or four crops a year. Vats previously used by the brewery housed hundreds of plants, police said.

Molson closed the brewery in 2000, and sold the building to a company that leases out space to a number of other businesses.

With files from The Canadian Press