Hans Julius Cahnmann, 93, an organic chemist and researcher who was a scientist emeritus at the National Institutes of Health, died of pneumonia and congestive heart failure Aug. 15 at his home in Bethesda.

Dr. Cahnmann came to the Washington area and joined NIH in 1950 and retired in 1977 as a research scientist in the clinical endocrinology branch of NIH's National Institute of Arthritis, Diabetes and Digestive and Kidney Diseases. He then continued his government research as a scientist emeritus until 1998.

Over the years, he worked on problems relating to the biochemistry and ailments of the thyroid gland. He may be best known for his work involving the mechanisms of the synthesis of thyroxine, the active hormone of the thyroid gland.

At NIH, he also helped train research fellows from overseas. He served as a visiting professor at universities in France, Israel and Japan.

He was the recipient of honors from the National Science Foundation and the American Thyroid Association. His professional memberships included the American Chemical Society, the Federation of American Scientists and the American Thyroid Association.

Dr. Cahnmann was born in Munich. He was a chemistry graduate of the University of Munich, where he also received a master's degree in pharmacy and a doctorate, summa cum laude, in chemistry. He fled to Paris to escape the Nazis, then came to this country in 1942. He was a research chemist at Mount Sinai Hospital in New York, where he received a patent for his work in a synthesis of Vitamin A.

His experiences escaping Europe were documented by Steven Spielberg's Survivors of the Shoah Visual History Foundation. His hobbies included art and music.

Survivors include his wife of 54 years, Ruth, of Bethesda; a son, Stephen, of New York; two daughters, Vivian Francesco of New Hope, Pa., and Catherine Cahnmann of Gaithersburg; a brother; two sisters; and a grandson.