Late Thursday firefighters wade at the edge of the crater left by the San Bruno explosion earlier that evening. Now filled with water from fire hoses, the roughly 15-foot-deep (4.6-meter-deep) hole is about 30 feet (9 meters) long and 20 feet (6 meters) wide, according to San Francisco's KGO TV news.
Though the San Bruno fire's source is still a subject of investigation, most gas pipeline accidents are due to digging projects, Nicor Gas executive Rocco D'Alessandro said during testimony at a June U.S. Senate hearing on pipeline safety. Speaking on behalf of the American Gas Association, D'Allessandro argued for the reauthorization of current federal pipeline-safety laws.
Some critics, though, argue that the laws don't do enough to protect the 70 million U.S. households that rely on gas pipelines for heat. For example, Carl Weimer, executive director of the nonprofit Pipeline Safety Trust, argues for rules limiting how close homes can be to pipelines.
"There aren't any regulations at all about setbacks," Weimer told the Washington Independent news site in August. "You can build a house right next to a pipeline."