The objective of this research was to provide human decompression data, including the occurrence and timing of resulting DCS cases, in a range of depths and bottom times which are inadequately represented in the Primary Air and N2-O2 data set. The occurrence of DCS was examined in 57 man-dives to depths between 8.5 and 12.2 msw (28 and 40 fsw) for six hours on air. During exposure, divers exercised using a bicycle ergometer at a moderate workload (100 watts) on a 50% work/50% rest cycle. After six hours bottom time, divers were immediately brought to the surface. Three DCS cases and two marginal DCS cases resulted from the deepest depths of 11.6 and 12.2 msw (38 and 40 fsw). The data from these and other dives were added to a master data base for diving at the Naval Medical Research Institute.