ASTM Committee G04 on Compatibility and Sensitivity of Materials in Oxygen Enriched Atmospheres was formed in 1975. G04 meets twice a year, usually in April and September, with approximately 35 members attending two to three days of technical meetings capped by a presentation on relevant topics concerning the oxygen industry. Committee G04 also periodically sponsors symposia. The Committee, with current membership of over 77 , has jurisdiction for 21 standards, published in the Annual Book of ASTM Standards, Volume 14.04. G04 has 3 technical subcommittees that maintain jurisdiction over these standards. Information on this subcommittee structure and G04's portfolio of approved standards and Work Items under construction are available from the Lists of Subcommittees, Standards and Work Items below. These standards have and continue to play a preeminent role in all aspects important to the selection of materials, configuration and application intended for use in systems subjected to enriched oxygen atmospheres.