Gordon Eldon Casey, 34, a staff member of the defense suncommittee of the House Appropriations Committee, died of asphyxiation yesterday in an accidental fire at his home in Falls Church.

A Fairfax County police spokesman said a smoldering pipe apparently ignited a chair on the first floor after Mr. Casey had gone upstairs to bed. He was the sole occupant of the house.

Mr. Casey came to Washington in 1973 as a temporary staff member of the subcommittee and became a full-time employe the following year. He was responsible for reviewing the research and development budget of the Defense Department.

Rep. George H. Mahon (D-Tex), chairman of both the Appropriations Committee and its defense subcommittee, called Mr. Casey and "invaluable asset" to the committee and praised his "depth of knowledge" on the defense Department's research and development programs.

Born in Lovell, Wyo., Mr. Casey grew up in Casper. He attended Casper Junior College and graduated from the University of Wyoming in 1965.

He then joined the General Accounting Office as an auditor, working in the Denver regional office until 1970, when he was transferred as supervisory auditor to the Far East branch in Honolulu. He traveled extensively to Korea, Okinawa, Taiwan, South Vietnam and Kwajalein Atoll in the Marshall Islands, conducting GAO audits.

Mr. Casey was reassigned to the Denver office as supervisory auditor in 1972.

He is survived by his parent, Mr. and Mrs. Eldon A. Casey, and a brother, Curt John, of Casper, and a sister, Karlene Virginia Richards, of Denver.