Five years ago, an old well casing broke at the SoCalGas-owned Aliso Canyon gas storage facility near Porter Ranch, Los Angeles. Some 100,000 metric tons of methane unfurled into the air. It became the largest gas leak in American history. Many residents believe it led to long-term health effects such as chronic coughs and even cancer. They have unexpectedly become environmentalists, and they want the Aliso Canyon gas facility shut down.