Treated Wood Waste Disposal in California
The state of California requires that wood waste that has been preservative treated must be disposed per the regulations in the Alternative Management Standards (AMS) for Treated Wood. While the AMS has been in place for nearly three decades, it was reaffirmed by passage of AB 332 in 2021.
The website, TWWDisposal.org, has been created to provide comprehensive information for those disposing of TWW within California. The website feature information specific to those users disposing of TWW, from households to businesses and large quantity generators.
Specific sections include identifying TWW, handling, storage, labeling, transportation, notifications, recordkeeping, reuse and TWW prohibitions.
For complete information on the TWW disposal, review the following:
- TWWDisposal.org – Western Wood Preservers Institute
- Approved landfills – California Water Boards
- Treated Wood Waste – California Dept. of Toxic Substances Control
California Proposition 65
Under the state’s Proposition 65, wood dust — from both untreated and treated wood products — is subject to requirements for providing a clear and reasonable warning before knowingly and intentionally exposing anyone to chemicals that are known to the state to cause cancer or birth defects or other reproductive harm.
To meet the Prop 65 requirements, a warning sign with the language shown in the image should be displayed “either at the point of sale or display of the raw wood products in a manner likely to be seen by the purchaser.” For additional information on the Prop 65 requirements, review the state Office of Environmental Health Hazard Assessment website at www.p65warnings.ca.gov/products/wood-dust.