Dr. Vann has spent his career in environmental physiology and operational diving with emphasis on understanding the physiology of decompression illness (DCI) and on developing procedures to avoid DCI. Beginning at Ocean Systems in 1967, he served as a Diving Engineer where, among other duties, he learned to compute decompression tables and acted as an experimental subject for dive trials to 650 feet. This was followed by four years in the Navy, two as the Diving Officer for Underwater Demolition 12. After receiving a Ph.D. in Biomedical Engineering at Duke University in 1976, he joined the faculty of the Duke Hyperbaric Center where he conducted experiments to investigate bubble formation and inert gas exchange, developed decompression procedures for scientific diving, and developed methods currently used by astronauts during extravehicular activity from the Space Station. As Research Director for the Divers Alert Network since 1992, he has investigated the causes of fatal and non-fatal injuries and published on dive computers, nitrox diving, flying after diving, prognostic factors in DCI therapy, flying with DCI, flying after DCI therapy, and first aid oxygen at sea level for DCI.