Police agencies across the Greater Toronto Area made dozens of arrests Tuesday as part of a major offensive against the illegal drug trade in Ontario.

Twenty-nine search warrants were executed in Toronto and other southern Ontario regions, including York, Durham and Kitchener-Waterloo.

Police told CTV Toronto that the arrests were part of Project Domo – a massive offensive against the cocaine trade in and around Toronto.

They allege that several small networks of drug dealers were working together to traffic drugs across the GTA.

Police said just under $2.5-million worth of drugs was seized as part of Project Domo, including quantities of cocaine, ketamine and ecstasy. Nine firearms were also seized in the raids.

Police said they made 22 arrests over the course of the raids.

Investigators say Project Domo has been ongoing for more than a year and is related to the raid of a Toronto biker club in May.

The raids came on the same day as officers in York Region made a giant drug bust of their own, just before noon, when they stormed an industrial marijuana grow-operation in Scarborough that is thought to contain an estimated $20-million worth of plants.

The bust involved dozens of officers, said witness Mary Donnolly.

“They just converged on the one building and then just stormed out in full riot gear with their oxygen masks on, and they had their weapons slung over their shoulders and they just went into the building,” said Donnolly.

The warehouse in Scarborough contained between 8,000 and 10,000 marijuana plants in various stages of growth, in what police Det. Const. Barry Smith described as “a sea of green.”

Even police were surprised by the scope of the bust, Smith told CTV Toronto.

“We knew what we were going to find, but the numbers? No. It’s a little overwhelming to walk in there and see this grown operation,” Smith said.

The bust in Scarborough was one of five search warrants, in Brantford, Toronto, Markham and Mississauga, that York Regional Police executed in relation to the investigation on Tuesday.

Eight men are facing charges in connection to the marijuana grow-operations.

With files from CTV Toronto’s Zuraidah Alman