that's how pg and e /khrarpblgs us. you have the big main. usually there are 60 or a hundred or 50. the little guys are 20-15-30. if you want to shut off the power you shut off the little guys first than the main. when you throw a switch there is the arch. like water when water flows in an old house any you shut it off quick you get the hammer effect? that's like electricity. is it safe to do it if you smell natural gas? show of hands. >> nobody has their hands up. it's not safe to flicking any switches if you smell natural gas. how about if there is smoke coming out of an outlet. if you shut this off in an area where there is no gas, good idea. >> just about anything can be a hazardous material, cleaners, solvants, hair products anything can be hazardous. they are every where. the only time they are hazardous if they are misused our there is a disaster. do you see these in san francisco? that's probably propane. we have a port. in an industrial area. it identified where they are stored. are there hazardous storage places in this air? no. are there a dry cleaners? yes. who remembers