Early morning 2-alarm fire damages 3-story Noe Valley residential building

SAN FRANCISCO -- A smoky 2-alarm fire spread through a 3-story residential building in San Francisco's Castro District early Wednesday, sending seven residents including two children scurrying for safety.

San Francisco Fire Captain Jonathan Baxter said 911 calls came in a little after 4 a.m. reporting a blaze in a building in the 1100 block of Castro St.

When firefighters arrived, they discovered the fire had spread in the building. 

"This fire quickly grew to a 2-alarm fire bringing 70 firefighters to the scene," Baxter said as the crews battled it from spreading to other buildings in the densely populated neighborhood.

All seven residents were able to escape safely. There were no injuries reported among the residents and firefighters.

The fire was brought under control in about an hour.  Baxter said the source of the fire had been traced "a heating source and deemed accidental."