Specifies requirements for personnel, equipment and procedures used in occupational underwater operations in up to 50 m depth of water using compressed air or similar oxygen-nitrogen mixtures as the breathing medium. Also gives details on compression chamber support, accident reporting and medical requirements for occupational diving operations. Appendices include a suggested content of an employer’s diving operations manual, metric and imperial decompression tables (with procedures for their use), guidance on the treatment of decompression illness and guidance for medical practitioners conducting diving medicals.