Wood Treated with Preservatives

Treated wood is banned from disposal in the garbage.
Most Sonoma County Refuse Disposal Sites do not accept treated wood for disposal. All wood treated with preservatives is subject to California's Hazardous Waste Control Law and may only be accepted at approved facilities.

Treated wood refers to dimensional lumber treated with chemicals that protect wood from rotting due to insects and microbial agents. Chemicals include arsenic, chromium, copper, creosote and pentachlorophenol which are hazardous to humans and the environment. Identification is not difficult as long as you know the characteristics.

How to identify treated wood
Look on the surface of the wood for small slits. These are numerous, staggered along the board and look like staple slits. They help with deeper chemical penetration and retention. Most pressure-treated wood has these slits. Examine the wood especially the edges, for a green tint. When the lumber is young, this will be the most identifiable sign of pressure-treated wood. As it ages it will fade to a dull gray color.

Examples of pressure treated wood preservative include:

CCA (Chromated copper arsenate)
Common uses: sill plates, trusses, joists

Creosote
Common uses: railroad ties

Pentachlorophenol
Common uses: phone poles, some fence posts

Copper based such as alkaline copper quaternary (ACQ) and copper boron azole (CBA)
Common uses: decking, landscape timbers

Borates
Common uses: sill plates, trusses, joists

Other wood preservatives

Resources for treated wood recycling

Department of Toxics Substances Control Board

California Department of Resources Recycling and Recovery (CalRecycle)

Hours listed on this page may change without notice.