Fire retardant wood is treated with what?

• A. Oils
• B. Resins
• C. Water repellents
• D. Mineral salts

Answer: (D)

Wood treated to resist fire relies on mineral salts. These inorganic salts, often phosphates or borates, are introduced into the wood to disrupt combustion as it heats. They promote the formation of a protective char layer, absorb heat by releasing water, and slow down the flame’s advance, giving more time for evacuation. Oils and resins are flammable and can fuel flames, so they don’t provide reliable fire resistance. Water repellents mainly prevent moisture ingress and don’t alter the chemical burning behavior of the wood. Minerals stay in the wood and chemically interfere with burning, making them the effective fire-retardant choice.