Dorothy Hill Gersack, 72, a retired employe of the National Archives and a member and former secretary of the Bethesda Fire Board, died of cancer Jan. 5 at the home of her daughter in Ellicott City, Md.

Mrs. Gersack was born in Livingston, Ill. She earned bachelor's and master's degrees in library science at the University of Illinois. She moved to Washington in 1936 to begin her career at the National Archives. She helped develop techniques that are now widely used in the government for describing, appraising, retaining and disposing of records.

She lived in Bethesda until 1975, when she retired from the Archives. After that, maintained homes in Delray Beach, Fla., and Ruidoso Downs, N.M. She was appointed to the Bethesda Fire Board in 1964 as the representative of the Old Georgetown Road Citizens Association and was its secretary from 1969 to 1975.

Mrs. Gersack was a fellow of the Society of American Archivists and edited its journal, The American Archivist. She also was a member of the American and D.C. library associations and the Regional Catalogers Association.

Her husband, Joseph Robert Gersack, died in 1980.

Survivors include a daughter, Judith Ann Vettori of Ellicott City; a sister, Marjorie Seitsinger of El Paso, Tex., and four grandchildren.