"The bends," or decompression sickness, is a health hazard associated with pressure changes during diving underwater. At the water surface, a column of air weighs 14.7 pounds per square inch and this corresponds to atmospheric pressure or one atmosphere. When divers go underwater, they experience the weight of the water in addition to the atmospheric pressure. A 33-ft. (10-m) column of water weighs 14.7 pounds per square inch. Thus, pressure increases by 1 atmosphere for every 33 feet of descent underwater.

Nitrogen comprises almost 80% of atmospheric air and normally this gas does not dissolve in body tissues to any great extent. However, during dives, the increased pressures force nitrogen gas into solution in body tissues, especially within adipose tissue. Because the blood supply to adipose tissue is not great and since nitrogen gas diffuses slowly, it takes hours for the equilibration of nitrogen to occur between body tissues and air.

The potential...