Chilliwack RCMP say they have busted the largest marijuana grow-op ever found in Chilliwack.

The grow-op in an underground bunker on Nixon Road had 11,520 marijuana plants valued at over $3 million, police said.

One male suspect, unknown to police, was arrested and held in custody while the investigation continues.

Chilliwack RCMP officers and the Lower Mainland Emergency Response Team executed a search warrant at the property in the 7600-block Nixon Road at 8 a.m. Wednesday.

Police said a Quonset hut had been built over top the bunker giving the illusion of a legitimate out-building on the property.

Water was being drawn from a nearby fish-bearing creek, and chemicals were being dumped onto the property with an unknown environmental impact.

BC Environment Ministry were called in to correct any environmental damage, and steps were taken to ensure the property itself is never used for a grow-op again.

Police estimate more than $400,000 worth of electricity was stolen to power the grow-op.

“While we cannot confirm any links to organized crime at this point, the level of sophistication of this grow-op suggests many people were involved in establishing and running this operation,” RCMP Cpl. Lea-Anne Dunlop said.

There were two booby traps designed to spray bear spray at anyone entering the property, and security cameras were set up to monitor the grow-op from the house.

A sub-floor had been built in the hut concealing an elevator-style hydraulic lift that provided access to the underground bunker where four separate grow rooms were located.

“Dismantling a grow of this magnitude take a large coordinated effort,” Dunlop said, and police were assisted by the City of Chilliwack, the Chilliwack Fire Department and BC Hydro.

Police are asking anyone who saw any suspicious activity in the rural area to call the Chilliwack RCMP at 792-4611. Anonymous tips can be made to Crime Stoppers at 1-800-222-TIPS or online at www.chilliwackcrimestoppers.ca