CHINO HILLS (CBSLA.com) — A large-scale marijuana growing operation was discovered Monday after firefighters responded to a residential fire in San Bernardino County.

The marijuana grow was discovered around 3 p.m. at a 3,500-square-foot home in the 2100 block of Old Carbon Canyon Road in Chino Hills, the San Bernardino County Sheriff’s Department said.

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“Nearly every room was converted for cultivating marijuana utilizing a hydroponics method,” officials said.

A total of 394 marijuana plants and a large amount of processed marijuana were seized. An unknown number of plants were also destroyed in the fire.

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Officials say the fire started in a room where cultivation equipment was plugged in to an outlet.

No suspects were in the home at the time of the fire.

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Investigators are asking anyone with information on the suspects to contact the Sheriff’s Narcotics Division at (909)890-4840.