Wood - Treated
Treated wood is wood treated with a chemical for the purpose of resisting decay. Examples include pressure-treated dimensional lumber, creosote-treated railroad ties, and telephone poles.
Pressure treated, preserved wood, or treated wood waste (including the sawdust), referred to as TWW, has preserving chemicals like arsenic, creosote, and copper. When outdoor structures built with preservative treated wood – such as decks, gazebos, fences and retaining walls – are demolished and discarded, the wood is considered TWW.
TWWDisposal.org has fact sheets and outreach materials on the appropriate handing, disposal (landfills that accept TWW), and other management of treated wood waste for residents and for facilities that may receive or handle treated wood waste. Spanish translation is enabled on their website.
Painted, engineered, stained, lacquered, plywood/composite, and wood painted with "copper green" may go in the garbage.