On Aug. 1, Pierce MacNair, president of Griffith Consumers of Cheverly for the past 15 years, will retire. Succeeding him will be Walter Meighan, executive vice president.

Almost 100 years old, Griffith Consumers is one of the area's leading fuel oil distributors.

Under MacNairs leadership, the company streamlined its fleet/service operation and expanded its oil supply network. He also expanded the firm into Baltimore, Frederick and Oxon Hill and was instrumental in establishing Griffith's new headquarters in Cheverly Industrial Park.

Meighan has been with Griffith Consumers for 16 years.

Howard C. Lewis jr. has been named administrator of the George Washington University Health Plan. He was previously assistant director of Roger Williams General Hospital in Providence, R.I.

J. Donal Durand has joined the Transportation Association of America as vice president-general counsel.

Shelia Moore Campbell has joined Earle Palmer Brown as account group supervisor. Linda M. Davenport also joined the public relations firm as an account executive.

Robert E. Stewart has been elected president of Maryland National Industrial Finance Corp. In addition, Peter S. Bird has been promoted to senior vice president and Thomas E. Kane has joined the company as vice president and regional manager if its Baltimore office.

Mavis A. Wright has been named district marketing manager and Bruce R. Davidson has been appointed senior marketing representative for conventions and company meetings for Delta Air Lines Inc.

Mary Ann Kennedy has joined Fairfax Telecommunications Inc. as executive administrator.

Willard R. Edwards, a computer specialist for the Social Security Administration, has been elected chairman of the D.C. chapter of the Association for Computing Machinery

James N. Sites has been appointed vice president for communications of the Chemical Manufacturers Association.

Jeff R. Hart has been named acting executive director for the Pension Benefit Guarantly Crop., succeeding Matthew M. Lind, who resigned.

Delores Ebert has been named vice president of the Atlas Employment Agency Inc.

Dr. Milton Harris, founder of the Harris Research Laboratories in Washington, has been named the 1980 recipient of the American Chemical Society's Priestley Medal, the highest honor in American chemistry. Dr. Harris initiated research that led to the development of the cold permanent wave, shrinkproof wool and a revolution in shaving systems. He is a former vice president and director of The Gillette Co.

John D. Davis Jr., Latane F. Gaylor. Lillian Karmel and Laura M. Perry have been elected vice president at The Riggs National Bank of Washington.