Methane (CH4) is produced from the decay of organic matter and is hazardous in confined spaces because it can displace oxygen, leading to dizziness, unconsciousness, and asphyxiation. Which statement best describes this risk?

Methane (CH4) is produced from the decay of organic matter and is hazardous in confined spaces because it can displace oxygen, leading to dizziness, unconsciousness, and asphyxiation. Which statement best describes this risk?

• A. It increases oxygen levels.
• B. It can displace oxygen, causing oxygen deficiency.
• C. It cleans the air by absorbing pollutants.
• D. It emits a strong odor when present.

Answer: (B)

In confined spaces, the danger comes from gases that don’t contribute to breathable oxygen but can fill the available space, reducing the amount of oxygen you can inhale. Methane is such a gas: it isn’t toxic at typical exposure levels, but as it builds up, it dilutes the oxygen partial pressure in the air. That lowers the oxygen concentration to unsafe levels, leading to dizziness, loss of consciousness, and potentially asphyxiation. Methane is colorless and odorless, so it won’t notify you by smell, and it does not clean the air or absorb pollutants. The core risk described is that methane can displace oxygen, causing oxygen deficiency.

In confined spaces, the danger comes from gases that don’t contribute to breathable oxygen but can fill the available space, reducing the amount of oxygen you can inhale. Methane is such a gas: it isn’t toxic at typical exposure levels, but as it builds up, it dilutes the oxygen partial pressure in the air. That lowers the oxygen concentration to unsafe levels, leading to dizziness, loss of consciousness, and potentially asphyxiation. Methane is colorless and odorless, so it won’t notify you by smell, and it does not clean the air or absorb pollutants. The core risk described is that methane can displace oxygen, causing oxygen deficiency.