Burning Pressure-Treated (Tanalised) Wood: Health Hazards and Safer Alternatives

Why You Should Never Burn Tanalised Wood

Tanalised (pressure-treated) wood contains copper-based preservatives (copper azole, ACQ – alkaline copper quaternary; formerly CCA – chromated copper arsenate). Burning releases toxic chemicals.

Hazards

• Arsenic (CCA-era wood pre-2004): Carcinogen; acute toxicity. Ash contains concentrated arsenic.
• Copper compounds: Respiratory irritant; metal fume fever.
• Dioxins/furans: Formed during incomplete combustion; persistent, bioaccumulative, carcinogenic.
• Particulate matter: Fine particles (PM2.5) carry toxins deep into lungs.

Identification

• Greenish tint (fresh), fading to gray.
• End tags/stamps: "Treated," "UC4," "ACQ," "CA," or old "CCA."
• Incising marks (slits) on surface for preservative penetration.

Safe Disposal

• Landfill (lined) – check local regulations.
• Construction & demolition recycling facilities (some accept).
• Never burn in fireplace, wood stove, fire pit, or campfire.

Safe Firewood Alternatives

• Seasoned hardwoods (oak, maple, ash, hickory).
• Kiln-dried untreated lumber scraps.
• Manufactured logs (wax/sawdust).