Treated Wood & Creosote
Preserved wood resists rot and insects because it carries chemicals: copper-based preservatives in modern pressure-treated lumber, older arsenic-based treatments, and creosote or pentachlorophenol on railroad ties, utility poles and pilings. Those chemicals can irritate the skin and eyes, poison if burned or swallowed, and, with some older products, cause cancer risk with heavy exposure.
- Carpenters & Deck Builders
- Landscapers
- Utility & Railroad Workers
- Homeowners
Types of treated wood
| Type | Typical uses | Main concern |
|---|---|---|
| Copper-based (ACQ, CA, micronized copper) | Decks, fences, framing near the ground | Skin and eye irritation; wood is corrosive to some metals, so use fasteners rated for it |
| CCA (chromated copper arsenate) | Older decks and playsets; still used in some industrial applications | Contains arsenic. Not used in most residential lumber in the U.S. since the early 2000s, but old wood is still around |
| Creosote | Railroad ties, utility poles, pilings, marine and landscape timbers | Skin burns and rash, sun-triggered skin reactions, fumes, cancer concerns with long exposure |
| Pentachlorophenol (“penta”) | Utility poles and crossarms | Skin and eye irritation; toxic with heavy exposure |
Labels, tags and the manufacturer's handling sheet show the preservative. Read them. See Safety Data Sheets.
Hazards
- Skin and eye contact: fresh creosote can cause burning, blisters and dermatitis, and skin exposed to sun afterward can burn more easily. Sawdust irritates eyes. See Skin Disease & Dermatitis.
- Dust: cutting and sanding treated wood makes dust containing preservative. Inhalation and swallowing from dirty hands are the main routes. See Wood Dust.
- Smoke and fumes: burning treated wood releases toxic compounds, including arsenic or creosote fumes. Never burn it in stoves, fireplaces, fire pits, or open fires, and not in a burn pile.
- Hot weather: creosote can ooze, drip and give off vapors on hot days. See Heat Illness.
- Heavy items: ties and poles are heavy and awkward. See Lifting & Ergonomics.
- Environmental harm: creosote and preservatives harm water and soil. Keep it away from wells, ponds, gardens and food.
Safe handling
- Wear long sleeves, long pants, gloves and eye protection. Use chemical-resistant gloves for creosote or fresh-treated material. See Hand Protection and Chemical-Protective Clothing.
- Cut and drill outdoors or in a well-ventilated area. Use a dust mask or a respirator for sanding and sawing as the SDS and assessment call for. See Respiratory Protection.
- Use vacuum or wet cleanup, not dry sweeping or compressed air. See Dust Control Methods.
- Wash hands and face before eating, drinking or smoking. Don't eat in the work area.
- Wash work clothes separately from other laundry, and remove dusty clothes before entering the house or vehicle. See Take-Home Contamination.
- Apply a sealant or finish on decks, tables and benches if the maker recommends it, and use treated wood only where it is allowed. Don't use it for cutting boards, countertops, animal feed troughs or beehives, or where it will touch food or drinking water.
- Don't use creosote ties or poles in play areas, gardens or indoor spaces.
If you're exposed
- Skin: wash right away with soap and water. Remove contaminated clothing. Get medical advice for blisters or severe burning.
- Eyes: flush with water for at least 15 minutes and get medical help. See Eyewash & Showers.
- Swallowed or heavy exposure: call Poison Control at 1-800-222-1222 in the U.S. See Chemical Exposure First Aid.
Disposal
- Never burn treated wood, and don't use it as mulch or compost.
- Sawdust and scraps should be bagged and disposed of as the local landfill or waste authority requires. Rules differ by state, and some industrial treated wood has special rules. Call your waste authority.
- Utility companies and railroads often have their own disposal and recycling programs for poles and ties.
Treated wood checklist
- I know what preservative the wood has
- I cut, drill and sand outdoors with controls and the right respirator
- I wear gloves, long sleeves and eye protection, and wash up before eating
- I never burn it or use it where it touches food or drinking water
- I bag and dispose of scraps and sawdust properly
Standards & references
Last updated: