What atmospheric hazards are most commonly associated with work in confined spaces?

When working in confined spaces, the primary atmospheric hazards that can threaten worker safety include oxygen deficiency, oxygen enrichment, explosive gases, flammable gases, and toxic gases.

Oxygen deficiency occurs when the concentration of oxygen in the atmosphere falls below acceptable levels, which can lead to suffocation and unconsciousness. Conversely, oxygen enrichment is when there is too much oxygen, which can create an increased risk of fire or explosion.

Explosive gases and flammable gases pose significant risks in confined environments as they can accumulate in high concentrations, especially since airflow is restricted. These gases can ignite and cause explosions, leading to severe injuries or fatalities.

Toxic gases, which can be produced from chemical processes, combustion, or the presence of certain materials, can also accumulate in confined spaces and lead to poisoning or long-term health effects for workers exposed to them.

Given this understanding, the correct answer encompasses both sets of atmospheric hazards associated with confined spaces—oxygen levels and the presence of explosive or toxic gases, confirming the relevance of both A and C.