BERKELEY, CA – City leaders have revised a two-year program to power the city's fleet of nearly 200 trucks entirely on a derivative of vegetable oil, according to the Berkeley Daily Planet. Public Works Director Renee Cardinaux said the decision came after it was found that bacteria mold discovered in the cleaner burning fuel may have clogged engine filters and fuel injection pipes. Berkeley won acclaim by becoming the first U.S. city to convert its fleet to 100 percent biodiesel in January 2003. Last year the Environmental Protection Agency (EPA) awarded Berkeley the Environmental Award for Outstanding Achievement for the program. After the first year, Cardinaux said the city started receiving fuel of degraded quality from its vendor Golden Gate Petroleum. The city has returned to using a blend of 80 percent diesel and 20 percent biodiesel.