A 26-year-old male U.S. Navy submariner suffered an arterial gas embolism during pressurized submarine escape training. Routine pretraining medical screening revealed no history of asthma, pneumothorax or recent respiratory infection. Pulmonary function testing and posterioranterior/lateral chest X-ray were normal. He forcefully exhaled at the start of his ascent and developed neurological abnormalities including lightheadedness with lower extremity weakness and paresthesias after surfacing. He fully recovered after a U.S. Navy Treatment Table 6. This case represents the first report of an arterial gas embolism since the U.S. Navy resumed pressurized submarine escape training utilizing the Submarine Escape and Immersion Equipment suit. We discuss possible contributing factors and propose that his AGE was caused by pulmonary barotrauma due to a combination of low forced expiratory flow rates and an overly forceful exhalation during his ascent.