William B. Smithers, 79, a retired director and treasurer of the Lank Woodwork Co. who was active in civic and service groups, died of congestive heart failure Jan. 20 at Circle Terrace Hospital in Alexandria.

Mr. Smithers, who lived in Alexandria, was born in Baltimore and reared in Washington, where he attended the old Business High School. He received a bachelor's degree in accounting from Southeastern University in Washington.

He worked for a dairy in the Washington area and in Florida and North Carolina. In 1938, he joined the Rollway Bearing Co. in Syracuse, N.Y., and remained there until 1956, when he returned to this area and joined Lank Woodwork. He retired in 1970, but remained as a consultant to the firm until 1979.

Mr. Smithers was a board member of the Girl Scouts of America in Alexandria, a past chairman of the Alexandria City Republican Committee and a past president of Brookville Seminary Valley Civic Association. He also was a Mason and a member of Trinity United Methodist Church.

Survivors include his wife, F. Mae Lank Smithers of Alexandria; two daughters, Joan Postlethwait of Syracuse, and Emmy Rotenizer of Galax, Va.; a son, John, of Alexandria, and eight grandchildren.