Incident Report

1995-02-06Diver A had experience of servicing a type of valve used by diver B so one summers weekend before diving B asked A to help in servicing the first stage of Bs valves. A successfully stripped and rebuilt the first stage of the first valve then tested it by coupling it to a bottle and breathing from the second stage. A large lump of something unpleasant went down As throat. Further investigation revealed green mould in the second stage of As second valve. The valves had been kept in a sealed container for some time since last being used in a warm place without being cleaned. Words were exchanged! Diver A was ill for a week with an infection of the lungs.Open circuit equipment is not always kept clean the subject is not regularly discussed and training in this is rarely given. Note that rebreather users are trained in cleaning the tubes thoroughly between each use precisely to prevent the event outlined above. The contaminated volume in a demand valve is considerably smaller than in a rebreather but cleaning it is no less important. The original cave diving manual merely alludes to rinsing a valve after use without specifically addressing the reasons for this. It might be considered that such housekeeping is obvious but we must guard against such assumptions.