Atlantic Richfield, Los Angeles, announced that Edward M. (Mo) Benson is retiring as vice chairman and a director. No successor was named for the 65-year-old Benson, and a spokeswoman said his responsibilities have been divided among a number of executives. He will be given the title of vice chairman emeritus.
Benson joined Richfield Oil Corp., which later merged with Atlantic Refining Co., in 1947. He had advanced to vice president in charge of Arco's exploration and producing operations in 1968 when Arco brought in the first successful oil well on the Alaskan North Slope, the biggest field in North America.
He was named a director in 1973 and a vice chairman in 1980.