accessing the purge button, as the single hose would not normally free flow when raised above the head. The increasing popularity of the buoyancy compensator was another complication, as it is necessary to periodically vent it during an ascent to avoid a runaway expansion of the contents and an uncontrolled buoyant ascent. This requires the use of one hand. the other is needed to control the regulator and hold on to the other diver, a moderately complex set of simultaneous tasks. It is possible to coordinate these activities, but this requires greater skill than with the original procedure, and therefore more intensive training to perform reliably. Since running out of air was becoming less common, the procedure was practiced less often, and skills generally deteriorated. The use of a secondary (octopus) second stage or a bailout cylinder removes the necessity for this complex and relatively stressful procedure. In the 1990s there was also growing concern about the transmission of disease by sharing a mouthpiece, particularly as a better option was available at a reasonable cost. Dive Training magazine ran an article by Alex Brylske in November 1993 detailing the hazards of buddy breathing and the advantages of alternative systems, and over the following years the practice was phased out of most recreational diver training programmes in favour of the use of secondary second stages and where applicable, a controlled emergency swimming ascent. Alternatives Most recreational and professional diver training organisations would consider relying on buddy breathing from a single regulator as an unacceptable risk, as the use of a secondary demand valve (octopus) or second regulator, either from an alternative scuba cylinder, or from the primary scuba set, is a far more reliable and safe method of supplying emergency air to a diver who is part of a planned team or buddy dive, and a solo diver should carry their own emergency gas supply. There should never be a situation on a well planned and executed dive where two divers need to share a single demand valve, but the technique is still considered useful by some diving schools as it teaches control and hones skills under difficult circumstances. Buddy breathing is discouraged by many training agencies because other more reliable techniques and equipment exist. The technique needs training and regular practice by both divers if it is to be used successfully in a crisis; panic and task loading being the