Which of the following gas levels is generally considered unsafe in a confined space?

In a confined space, the safety of workers is paramount, and various gas levels can indicate unsafe conditions. The correct response indicating an unsafe condition is when the oxygen level falls below 19.5%.

Oxygen is vital for human survival, and an atmosphere containing less than 19.5% oxygen can lead to symptoms of hypoxia, including impaired mental and physical performance, loss of consciousness, and potentially death. The standard threshold of 19.5% oxygen is widely recognized in occupational safety regulations, signaling that the air is no longer safe for breathing without respiratory protection.

Understanding the significance of oxygen levels is crucial for ensuring safety when working in confined spaces. The other gas levels mentioned may be hazardous at certain concentrations, but the low oxygen level is a critical and immediate threat that necessitates urgent attention to protect workers’ health and safety.