The City of Berkeley celebrated a milestone on June 24, 2003, by becoming the first city of its size in the U.S. to transition to 100 percent biodiesel in its diesel vehicles. Biodiesel is a fuel made from renewable resources, such as fat or vegetable oil.The city held an exhibit and ceremony to celebrate the occasion. The exhibit featured a variety of diesel vehicles from the departments of Public Works, Parks, Fire, Police, and Health and Human Services.Biodiesel works in any diesel engine with few or no modifications. Among its advantages, according to the U.S. Environmental Protection Agency, are considerably reducing the emissions produced by petroleum-based diesel. It is safer to transport, store, and use, because it is not a hazardous material like petroleum products. Biodiesel also reduces dependence on foreign oil.