Treated wood waste (TWW) is defined as wood waste that has been treated with preserving chemicals that protect the wood from insect attack and fungal decay during its use. Examples include fence posts, sill plates, landscaping timbers, pilings, guardrails, and decking.
Because TWW contains hazardous chemicals, at elevated levels, it is subject to California’s Hazardous Waste Control Law. The Department of Toxic Substances Control (DTSC) has developed alternative management standards (AMS) for TWW that are based upon full hazardous waste requirements but are adjusted for the unique circumstances associated with TWW. Generators of TWW can presume their TWW is hazardous waste. Generators can then manage their waste in accordance with the AMS, including disposal at approved non-hazardous waste landfills. Upon acceptance at these approved landfills, the TWW, at that point, becomes non-hazardous waste pursuant to Health and Safety Code section 25150.8.