Abstract
A safe transition from a higher-pressure atmosphere to a lower-pressure atmosphere is achieved by means of a planned decompression process, usually through changes in pressure and/or the composition of the breathing mix as a function of time. However, the decompression process is influenced by a greater number of inherent1 factors than merely changes in pressure and composition of the breathing mixture, the values of which should be maintained within certain ranges. However, there are instances where control over them cannot be maintained, leaving elements of residual risk2 to the decompression process. The safety of decompression should be assessed, inter alia, by analysing this risk for each implementation of the decompression process.