Firefighters discovered a marijuana grow operation while battling a one-alarm blaze at a home in Novato late Monday night, a Novato fire battalion chief said.

At 11:23 p.m., the fire department received a report of fire in the 1800 block of Marion Avenue, Battalion Chief Bill Tyler said.

The fire was under control at 11:53 p.m., he said.

Based on a preliminary investigation, Tyler said the fire appears to have been electrical in nature and began in the basement.

The home's electrical system had been set up to illegally bypass the PG&E meter, Tyler said.

No one was at home when the fire started, and no injuries were reported.

The exact cause of the blaze remains under investigation.