23.5% Volume

Maximum " Safe Level" ; OSHA

21%

Oxygen Concentration of AIR (20.954)

19.5%

Minimum "Safe Level"; OSHA, NIOSH

17%

Impairment of judgment starts to be detected

16%

First signs of anoxia appears

16-12%

Breathing and pulse rate increases, muscular coordination is slightly impaired

14-10%

Consciousness continuous; emotional upsets, abnormal fatigue upon exertion, disturbed respiration

10-6%

Nausea and vomiting, inability to move freely and loss of consciousness may occur

6%

Convulsive movements and gasping respiration occurs; respiration stops and a few minutes later heart action ceases