Police have seized $11 million worth of marijuana from elaborate grow-ops set up in 48 highrise apartments in three east-end Hamilton apartments, authorities confirmed Thursday.

Investigators say it is the largest bust in the city's history.

After receiving a tip about grow-ops, police conducted an early-morning raid on Wednesday at six units at a building on Grandville Avenue.

The find led them to other apartments filled with dozens of plants, and detectives soon discovered grow-ops in two nearby buildings on Violet Drive and Delawana Drive.

Police were shocked at the sophisticated and large-scale operation.

Investigators are now looking for the organized group behind the drug scheme. No arrests have been made.

Residents of the buildings said they often saw men in their 20s coming and going from the units. There is no indication they lived in the dwellings.

City officials have been called to the buildings to determine if there are health risks associated with the drug labs.

Officials who run the apartments said they had no knowledge of what was going on, as there was no abnormal hydro activity detected. But some residents said they had reported unusual activity.

M.J. Dann says she complained many times to the building manager about the noise coming from one particular unit.

Other residents are fuming about the mess that's been left behind following the bust.

Police said kitchen stove outlets were circumvented and used for electricity, a common practice in grow-ops.

The electrical work associated with marijuana grow-ops significantly increases the risk of fire, creating dangerous environments for those who live nearby. Fumes and mould can also create health problems.

Police say this operation is indicative of the evolution of the marijuana labs.

Criminals began grow-ops in outdoor fields, but have since moved sophisticated operations into residential homes and now apartments.

Last November police in Toronto raided a highrise and discovered $6 million worth of marijuana spread through two-dozen units on nine floors.

Several people were arrested and charged, including the building's superintendent.

With a report from CTV's MairiAnna Bachynsky and files from the Canadian Press