The utility won't release its pipeline locations — even to the Fire Department — but we managed find the info
The remarkable thing is that much of the data the city doesn't have — and PG&E won't give up — can be pulled together from publicly accessible data. The major news media, particularly The Bay Citizen, have been pursuing the story and have run pieces of the map. Several newspapers and websites have published rough maps outlining where the major underground pipes are.
But as far as we know, nobody's done a full-scale look at what the existing public records show.
Using information that the U.S. Department of Transportation has put on the Web, we've managed to put together a pretty good approximation of the secret map PG&E doesn't want you to see.
We took a map from the DOT's Pipeline and Hazardous Materials Safety Administration and layered it over a map of San Francisco. The maps of the southeast part of the city are more accurate; the information on gas mains going through the north and west side of town are sketchier. But the lines appear to run parallel to major streets, and we've put together a guide that at the very least can tell you if there's a potentially explosive gas line in your neighborhood — and maybe even under your street.
Obviously, every house or business that has natural gas service — and that's most of San Francisco — is hooked up to a gas pipe, and those feeder pipes run under almost every street. But the gas in those lines is under much lower pressure than the gas in the 30-inch main lines shown on this map, where pressure can reach 200 pounds per square inch. It was a main pipe that blew up under San Bruno.
It's not surprising that the southeast — traditionally the dumping ground for dangerous and toxic materials — would have the most gas mains, and the most running through residential areas. One line, for example, snakes up Ray Street and jogs over to Delta Street on the edge of McLaren Park and near a playground. It continues under Hamilton and Felton streets, under the Highway 280 and onto Thornton Street before heading into the more industrial areas near Evans Avenue.
Another main line goes under the south side of Bernal Heights, running below Banks Street, around the park, then down Alabama Street to Precita Street, where it connects with 25th Street. That line then heads to Potrero Hill, where it follows Rhode Island Street to 20th Street.
Research assistance by Nichole Dial.