For 10 days in October of 2007, wildfires riding hot Santa Ana winds swept across Southern California, forcing nearly 1 million people to flee and killing 10. When the ashes cooled, investigators found that many of the blazes had been caused by electrical lines swaying or falling in the wind. So state regulators resolved to tighten fire safety rules for electric utilities. They quickly passed new regulations for Southern California and began developing rules for the rest of the state. It would take 10 years. On Nov.