Two volunteers with the St John Ambulance and Rescue Service in Guernsey at the controls of the recompression centre for the treatment of divers

Decompression sickness, often referred to as 'the bends' is a dangerous medical condition which can affect deep-sea or scuba divers who use oxygen tanks. Divers' bodies absorb nitrogen from the air they breathe, with more nitrogen taken in the deeper they dive. If a diver ascends slowly, the body releases this nitrogen with no effect, but if a diver ascends too quickly, the nitrogen forms harmful bubbles in the bloodstream or tissues. The only treatment for the bends is recompression.