What is a common hazard when using a CO2 extinguisher in an enclosed space?

• A. CO2 can displace oxygen and cause asphyxiation; ensure ventilation or evacuate if needed
• B. It leaves oily residue
• C. It can cause water damage
• D. It is ineffective on any fire

Answer: (A)

The main concept is that a CO2 extinguisher can create a serious asphyxiation risk in enclosed spaces. CO2 is a colorless, odorless gas that can quickly displace the surrounding air, lowering the oxygen level to dangerous amounts for anyone present. In a confined room, this buildup can happen rapidly, so it’s crucial to ensure proper ventilation or evacuate before or during use. This is why the statement emphasizes the need to ventilate or leave the area. The other options don’t fit: CO2 doesn’t leave an oily residue or cause water damage, and CO2 extinguishers are not universally ineffective on fires—they’re effective in appropriate situations (like electrical fires or small liquid fires) when used with safety in mind.