Pressure-treated wood — common in fence posts, decking, landscape timbers, railroad ties, and retaining walls — contains preserving chemicals like arsenic, chromium, copper, creosote, and pentachlorophenol. These chemicals are toxic and carcinogenic, which means treated wood waste requires special handling.

How to Identify Treated Wood

Look for these signs:

  • Surface indentations or incising marks from the treatment process
  • Greenish tint or dark brown discoloration
  • Manufacturer stamps or end tags identifying the preservative
  • Staining only around the perimeter when cut (not through the center)
  • Solid outer shell with interior rot
  • Distinctive chemical odor

Not treated wood: Natural unpainted wood and wood with surface finishes (lacquer, shellac, polyurethane, varnish) are not considered treated wood waste and can go in your regular disposal.

What You Cannot Do With Treated Wood

  • Do not burn it — burning releases toxic chemicals into the air
  • Do not chip, grind, or mulch it — this is prohibited by law
  • Do not put it in your green waste bin or any curbside cart
  • Do not remove identification markings — these help facilities handle it properly

Disposal Options

Treated wood waste must go to an authorized facility. Keep it separated from other materials during transport.

Note: HHW facilities do not accept treated wood waste.

Questions?