If good seals are involved and the diver is effectively rinsed, scrubbed down and rinsed again prior to breaking any existing seals, the probability of exposure to the pollutants can be minimized. Special care must be taken to clear hoses and fittings that interface with the life support system. A failure to rinse bladders and hoses which may later be linked to the divers mouth or lungs could provide a path to the host days after the dive. The use of snorkels, alternate air sources, oral inflation devices and hose connections should all be given careful attention since the can carry contaminants directly into the mouth. Recreational divers maybe well advised to place their regulator in their mouth and their mask over their nose before entering suspect water and keeping it there until they have safely exited the water where they can remove the regulator without needing to replace it.
Polluted water is a fact of our lives.
Adapted from Glen Egstrom, Ph.