Donald Knox Duvall, 73, a retired U.S. International Trade Commission administrative law judge and lawyer whose area of specialty was unfair import trade practices, died after a stroke Sept. 13 at Sibley Memorial Hospital. He lived in Washington.

A former State Department lawyer, he began serving as an administrative law judge with the Social Security Administration in 1970. He later worked for what was then the Department of Health, Education and Welfare and for the Occupational Safety and Health Review Commission.

After seven years with the International Trade Commission, he retired in 1984 and spent the following 13 years at the Washington offices of New York-based Kenyon & Kenyon, first as resident counsel and then as of counsel.

He was a fourth-generation Washingtonian and the 1943 class president of Wilson High School. Upon the completion of his freshman year at Yale University on the war-time accelerated program, he entered the Army in 1943 and served in Europe with an anti-aircraft battalion during World War II.

He later graduated from Yale and received a law degree from the University of Virginia, where he co-founded the John Bassett Moore Society of International Law in 1953.

He worked in private law practice in Northern Virginia and Washington, then joined the State Department as a staff assistant in the office of the secretary and later worked as a member of the board of review on the loss of nationality.

He wrote law-related articles and served on committees of professional law associations. He was a member of the Rotary Club of Washington, past director of the Yale Club of Washington and a lifelong member of Metropolitan Memorial Methodist Church in Washington.

Survivors include his wife of 39 years, Kathryn Anne Berry Duvall of Washington; two daughters, Donelle Kathryn Huth of Geneva, Ill., and Suzanne Berry Duvall of Washington; and a brother, Dale Malcolm Duvall of Bethany Beach, Del.