Edward Robert Nelson, 54, a retired government chemist who had lived in the Washington area since 1951, died Sunday at the Clinical Center at the National Institutes of Health.He had sarcoidosis, a chronic disease of unknown causes.

When he moved to Washington, Mr. Nelson spent a year with the National Bureau of Standards. From 1953 to 1964, he was a chemist with the Harry Diamond Laboratory of the Army Materiel Command. He spent the next two years at NIH's National Cancer Institute. From 1966 to 1971, he worked for the National Aeronautics and Space Administration. From 1971 to 1979, when he retired for reasons of health, he worked for the General Services Administration.

Mr. Nelson was born in Pittsburgh and reared in Berkeley, Calif. He was a graduate of the University of California at Berkeley and did graduate work at the University of Southern California. He served with the Army Air Forces in Panama during World War II.

He was a member of the American Chemical Society, the American Association for the Advancement of Science and the Alumni Association of the University of California at Berkeley.

His marriage to the former Mary Browning ended in divorce.

Mr. Nelson's survivors include a son, Robert B., and a daughter, Anne B., both of Beverly, Mass.; his mother, Anna G. Nelson of Berkeley, and a brother, Gary J., of Potomac.