As of July 1, all diesel sold in Portland, Ore., must contain at least 5 percent biodiesel, a mandate approved by the city council a year ago, according to City-owned diesel vehicles must use fuel with a biodiesel content of more than 20 percent. The rule also mandates that all gasoline sold in the city must contain at least 10 percent ethanol. City gasoline-powered vehicles that can operate on 85 percent ethanol will be required to do so. The council argued that the mandate will help Oregon farmers and reduce the city’s annual petroleum fuel consumption while not hurting vehicle owners, as vehicles can run on biofuels without modification.