If a vehicle using ethanol or methanol is on fire, which extinguisher should be used?

Alcohol-resistant Class B foam is the appropriate choice because it is specifically designed to combat fires involving flammable liquids, such as ethanol and methanol. These types of fires can be particularly challenging to extinguish due to the volatility and flammability of alcohol-based fuels.

Using alcohol-resistant foam creates a barrier between the fuel and the air, effectively smothering the flames and preventing re-ignition. Additionally, this foam is formulated to handle polar solvents, like ethanol and methanol, which behave differently than non-polar flammable liquids.

Other extinguishing agents could be less effective or even counterproductive. For example, water can spread the fire by causing alcohol to float and flow, while dust extinguishers are generally not recommended for liquid fires. Dry powder extinguishers might work in some cases, but they are not specifically tailored for alcohol fires, making alcohol-resistant foam the safest and most effective option in this scenario.