A dangerous atmosphere is defined by an oxygen deficiency of what percent?

A dangerous atmosphere is defined by an oxygen deficiency of what percent?

• A. 12%
• B. 16%
• C. 18%
• D. 21%

Answer: (B)

In mining safety, the amount of oxygen in the air is used to classify atmospheric risk. Normal air is about 21% oxygen. A dangerous atmosphere is defined by a significant drop from that level, and in this context the threshold is 16% oxygen. At 16%, the body's ability to take in oxygen is seriously compromised, leading to symptoms like dizziness, impaired judgment, loss of consciousness, and a rapid progression to life-threatening danger with continued exposure. This is why 16% is used as the defining point for a dangerous atmosphere. The other values represent either normal air (21%), a less marked but still deficient level (18%), or an extremely severe deficiency (12%), but the standard safety definition used here centers on 16% as the danger threshold.

In mining safety, the amount of oxygen in the air is used to classify atmospheric risk. Normal air is about 21% oxygen. A dangerous atmosphere is defined by a significant drop from that level, and in this context the threshold is 16% oxygen. At 16%, the body's ability to take in oxygen is seriously compromised, leading to symptoms like dizziness, impaired judgment, loss of consciousness, and a rapid progression to life-threatening danger with continued exposure. This is why 16% is used as the defining point for a dangerous atmosphere. The other values represent either normal air (21%), a less marked but still deficient level (18%), or an extremely severe deficiency (12%), but the standard safety definition used here centers on 16% as the danger threshold.