Development Of Hearing Conservation Standards For Hazardous Noise Associated With Diving Operations

Spectral analyses reveal that wet-suited divers using certain underwater hand-held tools are exposed to intense noise. There is no general hearing-conservation standard (hcs) for noise exposure in wet environments and the existing literature does not provide a theoretical or an empirical basis for developing one. An interim hcs, based on equal sensory magnitudes, is developed and discussed. Temporary auditory threshold shifts resulting from controlled exposure to noise have been used to assess noise hazards. Research in progress at the Naval Submarine Medical Research Laboratory (NSMRL) in which divers are exposed to noise from three classes of hand-held tools is described. There is also a need for an hcs for noise exposure in dry hyperbaric environments, such as in diving chambers, and diving helmets. Since auditory sensitivity is diminished in hyperbaric gas, it is reasonable to assume that the existing hcs for surface pressure can be applied conservatively to dry diving situations. However, recent experience suggests that the surface hcs may be needlessly restrictive for hyperbaric gas environments. New data on this point recently obtained at NSMRL is presented.