About 20 people found themselves displaced Tuesday and one was receiving treatment for smoke inhalation after a three-alarm fire Monday night caused an estimated $700,000 damage to a building housing apartments and retail establishments in downtown San Diego.

The fire broke out in a commercial building topped by two floors of apartments at 831 Broadway, near Ninth Street, around 10:40 p.m. Monday, Lee Swanson of the San Diego Fire-Rescue Department said.

More than 50 firefighters battled the blaze, declaring a knockdown at 11:25 p.m., Swanson said, adding that some  apartments were damaged by the fire.

Damage was estimated at $600,000 to the structure and $100,000 to its contents, he said.

Someone’s pet dog died in the blaze but an ailing pet cat was rescued and revived by firefighters with a pet oxygen mask, Swanson said.

The cause of the fire was under investigation.

— City News Service

Chris Jennewein is founder and senior editor of Times of San Diego.