Abstract: During a SCUBA dive to locate oxygen welding gas cylinders in water that was 20 to 50 ft deep and 38 to 40 degrees F with a 20 ft visibility, Employee #1, a diver, ascended uncontrollably from a depth of about 45 ft suffering from extra-alveolar air syndrome, which caused massive cerebral and cardiopulmonary emboli. Employee #1 was equipped with a DUI shell-type dry suit. The suit was equipped with rubber seals, a neoprene collar, Viking inflator connector valve, DUI Whites exhaust valve, and neoprene boots. A single 80 cu ft air tank was the sole source of air for both Employee #1 and the dry suit. Evidence indicates that Employee #1 activated the valve to add air to his dry suit while swimming head down. The valve malfunctioned. The valve was stuck open, overinflating his suit.