What danger is created by excessive oxygen in a confined space?

Excessive oxygen in a confined space presents a significant risk because it can lead to an increased likelihood of combustion. When the concentration of oxygen in the air rises above normal levels (which is typically around 21%), flammable materials can ignite more easily and burn more intensely. This heightened risk arises because many materials that are normally considered safe under standard atmospheric conditions can become hazardous in an oxygen-rich environment.

For instance, materials that may not readily catch fire in regular atmospheric conditions can ignite quickly in a high-oxygen environment, leading to potentially explosive situations. This phenomenon is particularly crucial to understand in industrial settings or during rescue operations in confined spaces, where an unexpected increase in oxygen can have dire consequences.

Other possibilities, such as decreased visibility and equipment malfunction, do not directly relate to the risks associated with increased oxygen levels. While asphyxiation can be a concern in confined spaces, it is typically associated with insufficient oxygen rather than excessive amounts.