T. William Blumenauer Jr., 65, stepped down last Friday as president and chief executive officer of Columbia First Federal Savings & Loan Association, the second largest savings & loan association in the city.

A Washington native, Blumenauer joined Columbia as a teller in 1938, when its total assets were $4.5 million, and rose through the ranks to become president in 1968.

In February 1981, Columbia Federal merged with First Federal Savings & Loan Association, with total assets for 1981 of $914 million.

Dewitt T. Hartwell, former president of First Federal and executive vice president and chief administrative officer of the merged institution, will succeed Blumenauer, who will continue to serve as a member of the S&L's board.

Hartwell, who joined First Federal in 1958, was appointed a vice president there in 1965 and senior vice president in 1973 before becoming president and chief executive officer in 1978. At that time, First Federal's assets were $360.9 million. By the time of the merger, its assets had reached $403 million.

Other executive changes at Columbia First include the promotions of C. Gay Harrell Jr. from senior vice president to executive vice president; of C. Malcolm West from vice president to executive vice president; of J. Michael Millard from vice president to senior vice president, and of Walter Hall from vice president to senior vice president.

Clarence E. Kefauver Jr. and Henry E. Nichols continue as chairman and vice chairman, respectively.