In a report to the state Public Utilities Commission, Southern California Edison said it was investigating whether its electrical equipment caused the blaze. However, the utility had reduced that to under 16,500 as winds eased temporarily Monday night. Fire officials said PG&E transmission lines sparked that fire, which destroyed hundreds of homes and caused nearly 100,000 people to flee. While the biggest fires in California have been fully or significantly contained, more than 5,000 firefighters remain committed to 20 blazes, state fire officials said. Associated Press writer Amy Taxin in Orange County, California contributed to this report.