In oxygen components, even for high pressure oxygen service, It Is possible to use organic seals, lubricants, or filling liquids, provided their oxygen compatibility has been checked. However, fire incidents in oxygen systems still occur because these materials ignite and burn. There are many reasons, such as incorrect design, contamination, faulty operation, unsuitable materials, etc., why this happens. Another cause that is overseen very often is proper maintenance on the user's side. It is very important to replace in a component a worn out seal by the same one with Identical oxygen compatibility properties. On the part of the producer or distributor of materials, batch testing and also a quality assurance system play a key role In the safety of an oxygen component. Any change In the manufacturing process of a material, or in its composition, and even its further processing may have an Impact on its oxygen compatibility and finally on the component In which it Is used. Numerous Investigations by BAM over decades reveal the influence of minor constituents and fillers on a material's oxygen compatibility. The test results in this paper show how important It is to regularly perform batch testing on nonmetallic materials used for oxygen service and to have a quality assurance system that helps minimize incidents where unsuitable materials are chosen by accident. Copyright © 2009 by ASTM International,.