Former Unocal Chief to Retire From Chevron

Chevron Corp. said Executive Vice President Charles R. Williamson, the former chairman and chief executive of recently acquired Unocal Corp., was retiring, effective Dec. 1.

Williamson joined Union Oil Co. of California as a research scientist in 1977. He worked for the company in various capacities, climbing to the chief executive post in 2001. Williamson had said before that he would remain with Chevron for a few months to assist with the transition.

Chevron, the nation’s second-largest oil company behind Exxon Mobil Corp., acquired El Segundo-based Unocal in August for $18 billion.