Name two common safety hazards when entering manholes or sewers.

• A. Oxygen deficiency and toxic gases; engulfment.
• B. Ultraviolet exposure.
• C. High noise in daytime.
• D. Lack of sunlight.

Answer: (A)

Entering manholes or sewers involves confined-space dangers tied to the atmosphere inside. The most common hazards are oxygen deficiency and the presence of toxic gases, which can cause dizziness, unconsciousness, or death without warning. Engulfment is another major risk, since standing water, sewage, or loose materials can rapidly overwhelm or trap a worker who enters the space. These hazards are why a choice listing oxygen deficiency, toxic gases, and engulfment is correct.

Ultraviolet exposure, high noise, and lack of sunlight aren’t the primary hazards specific to entering manholes or sewers, so they don’t fit as the main safety concerns in this context.