 Xenon gas can be safely kept in normal sealed glass or metal containers at standard temperature and pressure . However , it readily dissolves in most <unk> and rubber , and will gradually escape from a container sealed with such materials . Xenon is non @-@ toxic , although it does dissolve in blood and belongs to a select group of substances that penetrate the blood – brain barrier , causing mild to full surgical anesthesia when inhaled in high concentrations with oxygen . 
