The sulfurous scent of a natural-gas leak hangs in the air as mail carriers wearing gas masks make rounds to mostly deserted homes in the Los Angeles neighborhood of Porter Ranch.
Life in the community of 30,000 people chiseled into the hills on the north rim of the San Fernando Valley has been upended by the break, which emits enough methane to fill the Empire State Building every day. San Diego-based Sempra Energy, which operates the fourth-largest underground storage field in the U.S. nearby, has said capping it could take two months.