Acie L. Byrd Jr., longtime D.C. activist on behalf of veterans, D.C. statehood and nuclear disarmament, in 1990. He was also a founder of WPFW-FM radio in Washington. (Carol Guzy/The Washington Post)

Acie L. Byrd Jr., a disabled Navy veteran who later became a prominent advocate for many causes, most notably military veterans who had been exposed to nuclear radiation, and who was a founder of Washington’s WPFW-FM radio station, died May 13 at a hospice in Arlington County. He was 77.

He had prostate cancer, his son, Derrick Birdsong, said.

Mr. Byrd served 16 years in the Navy, beginning in 1955. For several months in 1958, he was assigned to work at an atoll in the Marshall Islands in the Pacific, where U.S. nuclear weapons were being tested. He was part of a naval unit that retrieved equipment and supplies after nuclear explosions.

According to E. Cooper Brown, former general counsel to the National Association of Atomic Veterans (NAAV), the United States detonated 14 megatons of atomic weapons on the Enewetak atoll, where Mr. Byrd was assigned, or 380 times the combined force of the bombs dropped on the Japanese cities of Hiroshima and Nagasaki during World War II.

Amid growing concerns about safety, the United States stopped above-ground testing of nuclear weapons in 1962, a year before signing a test-ban treaty. The prohibition came too late for Mr. Byrd and other veterans, who began to experience a variety of serious health concerns.

“They were sending these guys into radiologically damaged areas, and these guys were being exposed to radiation,” Brown said.

In Mr. Byrd’s case, the problems included nerve damage in his face and recurring bouts of prostate cancer, first diagnosed when he was in his 30s.

Mr. Byrd later became a member of the NAAV and co-founded the International Alliance of Atomic Veterans, which advocated on behalf of military veterans affected by nuclear radiation. His efforts were considered crucial to the passage of the Atomic Veterans Relief Act of 1986, which provided compensation to military veterans whose health problems were shown to be linked to radiation exposure.

“Acie was one of the more active veterans on this issue,” Brown said. “He was a very imposing and impressive presence.”

Acie Lee Byrd Jr. was born Jan. 7, 1937, in Roanoke Rapids, N.C., and joined the Navy after high school. He left the Navy in 1971, settled in Washington and graduated in 1974 from the University of Maryland with a bachelor’s degree in economics and African American studies. He received a master’s degree in political science from Howard University in 1979.

Over time, Mr. Byrd became increasingly involved in a variety of causes, including civil rights, the abolition of the death penalty and a ban on nuclear weapons. In 1977, he was one of the founding members of WPFW, and he frequently appeared on the “jazz and justice” station as a commentator on politics and veterans’ matters. He served on the national board of the Pacifica radio network.

From 1978 to 1984, he worked with U.S. Rep. John Conyers Jr. (D-Mich.) to organize congressional support for a federal holiday honoring the birthday of the Rev. Martin Luther King Jr. The holiday was first observed nationally in 1986.

Mr. Byrd participated in many local and national political campaigns, including those of Del. Eleanor Holmes Norton (D-D.C.).

“People saw him as a man of principle,” Norton said of Mr. Byrd in an interview. “If you do not organize people, you do not accomplish anything. He was a movement man.”

In 1982, Mr. Byrd helped coordinate a march for nuclear disarmament in New York’s Central Park attended by an estimated 1 million people. He was also a key organizer of the 30th anniversary commemoration of the 1963 March on Washington.

“He was a good organizer,” said Jack O’Dell, a civil rights veteran and former adviser to King. “He knew how to deal with people and win their respect.”

Mr. Byrd chaired the D.C. Nuclear Weapons Freeze Committee, and in 1997 he was a founder of the Stand Up for Democracy in DC Coalition, an organization promoting statehood for the District of Columbia.

Survivors include two children from a relationship with Shirley Birdsong, Derrick Birdsong of Hyattsville, Md., and Monica Birdsong of Nashville; a stepmother, Sallie Garner Byrd of Roanoke Rapids; a sister; a brother; three grandchildren; and two great-grandchildren.

“Acie was thoughtful, and he knew how to listen,” O’Dell said. “He was always concerned.”