Large Explosion

Emergency workers patiently sifts through rubble of a burned down home, three days after a natural gas pipeline exploded into a deadly fireball in San Bruno, Calif., Sunday, Sept. 12, 2010. The remains of at least four people have been found, and authorities have said four are missing and at least 60 injured, some critically. Two people reported missing after blast were located Sunday, city spokeswoman Robyn Thaw said. (AP Photo/Tony Avelar)