David Platt Rall (August 3, 1926 – September 28, 1999) was a cancer specialist and a leader in environmental health studies, whose work in environmental health helped turn it into a scientific discipline. Rall also advanced public health and prevention. He directed the National Institute of Environmental Health Sciences from 1971 to 1990, year in which he retired. His work on toxicology and carcinogenesis was recognized by his appointment as the first director of the National Toxicology Program in 1978. He held the rank of Assistant Surgeon General in the United States Public Health Service. He also chaired the World Health Organization's Program on Chemical Safety.