During the later half of 2006, a new transportation fuel was introduced in California and the rest of the nation that is helping to dramatically improve air quality. Called ultra low sulfur diesel (ULSD) fuel, this new fuel is now the dominant fuel for diesel-powered trucks, cars and equipment. The transition to ULSD fuel in California, required by the U.S. Environmental Protection Agency and the California Air Resources Board, occurred on a slightly different timetable than the rest of the nation. For more information on ULSD, click on the appropriate link below:

ULSD in California
(Para leer en español el folleto sobre diesel ultra bajo en azufre - PDF)

ULSD in the United States
(Para leer en español el folleto sobre diesel ultra bajo en azufre - PDF)

Special note for some 2007 heavy duty trucks
Some heavy-duty diesel-powered model year 2007 vehicles are built with 2006 model year engines that are not equipped with sulfur-sensitive advanced emission control systems. These vehicles do not require ULSD fuel and the EPA does not require that these vehicles be fueled with ULSD fuel. See the attached letter from EPA (a pdf file) that addresses the issue.

For information on the clean air benefits of ULSD, please visit the Clean Diesel Fuel Alliance website at www.clean-diesel.org.