Abstract: A diving officer and Employee #1, a diver, were conducting a scientific dive. Employee #1 indicated to the dive officer, by hand signal, he was surfacing with an interim 3-minute safety stop (hover) at 15 feet of sea water (fsw). The dive officer ascended to safety stop as well. Employee #1's depth varied between depths of 12 fsw and 22 fsw. Employee #1 then signaled, by hand signal, to the dive officer that he was out of air and quickly rose to the surface. The dive officer followed, attempted to calm Employee #1. The dive officer attempted to provide alternate secondary stage, but Employee #1 did not accept this. The dive officer provided primary regulator, and Employee #1 accepted this. Employee #1 was not calming down so the dive officer unsuccessfully attempted to drop Employee #1's dive weight belt. The dive officer increased his own buoyancy by dropping his own weight belt, and initiated a tow of Employee #1 to the shore. Employee #1 was tethered by the dive officer's primary regulator. The dive officer attempted to remove Employee #1's weight belt a second time. This did not succeed. The dive officer then indicated that after several strokes to shore, he did not feel the presence of air bubbles or increased drag of Employee #1 in tow. The dive officer returned to shore, removed his diving gear, and then initiated the emergency call to the USCG and the employer. Employee #1 drowned and his body was recovered approximately one hour later in 11 fsw.