Confined Space Oxygen Deficient Environment

The number one cause of asphyxiation is oxygen deprivation. The air that we typically breathe as we go through our daily activities contains 21% oxygen. An oxygen deficient atmosphere contains less than 19.5% oxygen. Oxygen deficiency, or lack of oxygen, can cause fatigue, unconsciousness, and even death. Oxygen deficient atmospheres in a confined space may be due to nitrogen intrusion, welding, grinding, oxidation, or coating.

The following are warning symptoms to let you know that you are in an oxygen deficient atmosphere, which results in oxygen deprivation:

• 19.5% - Minimum acceptable oxygen level
• 15-19% - Decreased ability to work strenuously, impaired judgment and coordination, increased pulse
• 12-14% - Breathing difficulty, impaired judgment and coordination
• 10-12% - Respiration increases, lips turn blue
• 8-10% - Mental fatigue, fainting, nausea, unconsciousness, ashen face, vomiting
• 6-8% - 8 minutes: 100% fatal; 6 minutes: 50% fatal; 4-5 minutes: recovery is possible with treatment
• 4-6% - Coma within 40 seconds and death

As an attendant or authorized entrant, it is vital that you are able to recognize these symptoms in the event that you see them in another team member or yourself so that emergency procedures may be performed immediately.

To learn more visit our Confined Space Online Training web page.