Atlantic Richfield Co announced yesterday it will start selling a cleaner diesel fuel for Southern California municipal fleet vehicles.

The new diesel will have no more than 15 parts per million of sulfur, one-eighth the amount of sulfur of current diesel fuel. The company, which supplies about 20% of the state's 220,000 barrels per day, is also testing an even cleaner fuel, called EC Diesel, which contains only 5 to 10 ppm of sulfur.
Arco is trying to defend diesel's market share against competition from alternative fuels such as natural gas. The new fuel comes after a proposal by the California Air Resources Board to require sharp reductions in bus emissions. During its Jan. 27 meeting, CARB will consider a proposal requiring that urban buses be virtually exhaust-free by 2007.