What is the minimum oxygen percentage that indicates a hazardous atmosphere in excavations?

In confined spaces such as excavations, a minimum oxygen percentage of 19.5 percent is crucial for safety. Levels below this threshold indicate an atmosphere that may be hazardous, as oxygen is essential for human survival and normal functioning.

A concentration of oxygen that drops below this level can impair cognitive function, lead to a loss of consciousness, or even become life-threatening. When working in excavations, understanding and monitoring the oxygen levels is essential to prevent asphyxiation and maintain a safe working environment.

The standard threshold is set at 19.5 percent to provide a safety margin; the typical atmospheric oxygen level at sea level is about 21 percent. While various other levels indicate different conditions, it is vital for excavator operators and workers to be aware of the 19.5 percent level as the point below which the atmosphere is considered unsafe for work.