Oxygen Toxicity During Five Simulated Eight-Hour EVA Exposures to 100% Oxygen at 9.5 psia

We conducted a study to determine if oxygen toxicity occurs in a proposed extravehicular activity (EVA) pressure suit environment. Twelve male subjects were exposed to 100% oxygen at 9.5 psia for 5 consecutive days, 8 h/day while performing moderate exercise. No decompression sickness or venous gas bubbles were detected. Pulmonary function tests, physical exams, blood analyses, arterial oxygen saturation monitoring, and x-rays showed no evidence of oxygen toxicity. These results suggest that a 100% oxygen, 9.5 psia pressure suit environment could avoid both decompression sickness and oxygen toxicity during EVAs of comparable duration and physical activity.