Investigators say plumbers were working in the attic and it was a spark from a plumber's torch that ignited the blaze.
The flames were intense after the blaze broke out shortly after 3pm Thursday at the Arbor Ridge East Apartments here on Imperial Valley near Parramatta. You could see them shooting more than 10 feet into the air from the roof at one point. Firefighters had to pull a second alarm.
One eyewitness, Amy Vazquez, describes the chaotic scene she encountered when she returned home just after the fire began.
"The first thing I saw was this lady running with her baby. I asked her if she needed help. She just started crying in my arms. The baby was just a week old," said Vazquez.
Fire investigators say about 16 units were heavily damaged. Others were damaged as well.
The fire department says they had some issues here with a shortage of water because they were pouring so much on this fire when they got here.
The fire department says everyone got out OK and there were no injuries.
However, several dozen people remain outside the apartments here, unable to return home.