What oxygen level indicates a dangerous atmosphere in a confined space?

A dangerous atmosphere in a confined space is indicated by an oxygen level below 19.5%. When the oxygen concentration drops to this level, it presents serious health risks, including the potential for unconsciousness or death, as even brief exposures can adversely impact an individual's ability to operate safely. Adequate oxygen levels, typically around 20.9%, are necessary for safe breathing and cognitive function.

In confined spaces, air quality is crucial, and maintaining oxygen levels above 19.5% is a standard safety guideline to prevent asphyxiation and ensure a safe working environment. Recognizing this threshold is essential for those working in hazardous conditions to implement necessary safety measures, such as ventilation or the use of protective equipment, to ensure the oxygen concentration remains within safe limits.