Hurricane Harvey knocked out almost a quarter of the U.S. refining capacity. The average gas price in the U.S. is now about $2.64 for a gallon of regular, according to AAA, up about a quarter from last week. Now, Exxon Mobil says it’s working on restarting its Baytown refinery, the second largest refinery in the country. That means inspecting every part and system, securing housing and transportation for workers, and having roads, ship channels and pipelines open to bring in crude, then send out gasoline or other petroleum products. At the refinery itself, keeping things safe means allowing for more possible pollution, as workers vent or flare chemicals and get the plant going again.