▁the ▁other ▁in ert ▁components ▁are ▁elimin ated ▁( in ert ▁gas ▁counter diff usion ), ▁sometimes ▁resulting ▁in ▁raising ▁the ▁total ▁t issue ▁t ension ▁of ▁in ert ▁g ases ▁in ▁a ▁t issue ▁to ▁exceed ▁the ▁ambient ▁pressure ▁sufficiently ▁to ▁cause ▁b ubble ▁formation , ▁even ▁if ▁the ▁ambient ▁pressure ▁has ▁not ▁been ▁reduced ▁at ▁the ▁time ▁of ▁the ▁gas ▁switch . ▁They ▁conclude ▁that ▁" bre ath ing - gas ▁switch es ▁should ▁be ▁scheduled ▁deep ▁or ▁shall ow ▁to ▁avoid ▁the ▁period ▁of ▁maximum ▁su pers atur ation ▁resulting ▁from ▁decom pression ". ▁ ▁O xygen ▁decom pression ▁ ▁The ▁use ▁of ▁pure ▁o xygen ▁for ▁acceler ated ▁decom pression ▁is ▁limited ▁by ▁o xygen ▁to x icity . ▁In ▁open ▁circuit ▁sc uba ▁the ▁upper ▁limit ▁for ▁o xygen ▁partial ▁pressure ▁is ▁generally ▁accepted ▁as ▁ 1 . 6 ▁bar , ▁equivalent ▁to ▁a ▁depth ▁of ▁ 6   ms w ▁( met res ▁of ▁sea ▁water ), ▁but ▁in - water ▁and ▁surface ▁decom pression ▁at ▁higher ▁partial ▁press ures ▁is ▁rout in ely ▁used ▁in ▁surface ▁supplied ▁div ing ▁operation , ▁both ▁by ▁the ▁military ▁and ▁civil ian ▁contract ors , ▁as ▁the ▁consequences ▁of ▁C NS ▁o xygen ▁to x icity ▁are ▁consider ably ▁reduced ▁when ▁the ▁diver ▁has ▁a ▁secure ▁breath ing ▁gas ▁supply . ▁US ▁Navy ▁tables ▁( Re vision ▁ 6 ) ▁start ▁in - water ▁o xygen ▁decom pression ▁at ▁ 3 0   f sw ▁( 9   ms w