You should “Shelter in Place”, which means you should close all doors and windows, and turn off the heating or air-conditioning system, including fireplace vent to create the best seal. Turn the radio to KCBS, station 740 am, or turn on the television to a local bay area news station. You will be instructed as to what to do. You may also receive an automated phone call to inform you of what has occurred and how to respond.
