ENERGY

Unocal to Stop Diesel Fuel Sales in California: The Los Angeles oil company said it plans to stop selling diesel fuel in California by October, 1993, citing new clean air regulations. The company estimated that it will cost at least $100 million and require three years of planning and construction to comply with the California Air Resources Board’s new standards. Chairman Richard Stegemeier said Unocal couldn’t justify the investment. While the company studied alternative ways of producing diesel fuel to meet the standards, “all were un-economic,” he said. Meanwhile, Chevron Corp. said it has received certification from the Air Resources Board for a reduced-emissions formulation that meets the new diesel standards. The company said it plans to make the formula public and offer the rights to other California producers as part of its “commitment to improving air quality.”