Explosion can occur if which of the following is vented in an enclosed environment?

• A. Oxygen
• B. Hydrogen
• C. Nitrogen
• D. Methane

Answer: (B)

When a flammable gas is vented into a confined space, it can mix with the surrounding air to form an explosive atmosphere. Hydrogen stands out here because its flammability range in air is extremely wide and it requires very little energy to ignite. That means even a small amount of hydrogen leaking into an enclosed area can, if there’s an ignition source, ignite and explode. Oxygen left in the space supports combustion but doesn’t by itself create an explosive mixture without a fuel. Nitrogen is inert and doesn’t fuel explosions. Methane can be explosive as well, but hydrogen’s tendency to form explosive mixtures across a broad range of concentrations makes it the most dangerous choice in this scenario.