At what oxygen-deficient atmosphere percentage does poor judgment and blue lips occur?

The correct percentage range for poor judgment and blue lips to occur in an oxygen-deficient atmosphere is indeed between 10-12%. At this level of oxygen saturation, the body's ability to perform cognitive functions begins to deteriorate, leading to a decline in judgment and coordination. Additionally, the lack of sufficient oxygen supplied to the blood can manifest visibly, such as through the bluish discoloration of lips—known as cyanosis—as a consequence of inadequate oxygenation in the tissues.

In environments where oxygen levels fall into this range, individuals may experience not only impaired judgment but also a range of physiological effects that can affect their ability to operate safely and effectively. The threshold for serious symptoms typically begins to appear when oxygen levels are reduced to approximately 10-12%, which is particularly significant in safety-sensitive industries, medical settings, and emergency response scenarios. Understanding these effects is critical for those working in environments where oxygen levels could be compromised.