Updated Sept. 21, 2018
Marin County Fire Chief Jason Weber said the Irving Fire was started by a downed PG&E power line.
"The investigators determined the cause to be a power line that came down into the grass," Weber told KQED.
Meanwhile, a bill that would provide utilities liability protection has been signed by Gov. Jerry Brown.
Senate Bill 901 allows utilities like PG&E that caused massive wildfires across Northern and Central California to issue bonds to pay for huge liability costs.