With some common-sense precautions, it is safe to handle preserved wood products during your project.
Preserved wood may contain materials which cause skin irritation. Avoid frequent or prolonged skin contact with preserved wood. When handling the wood, wear long-sleeved shirts and long pants and use gloves impervious to chemicals (for example, gloves that are vinyl coated).
Follow good personal hygiene after handling preserved wood. Wash hands and any exposed areas thoroughly after handling preserved wood, especially before eating, drinking or using tobacco products.
Avoid inhalation of sawdust from preserved wood products. When sawing the wood, wear a dust mask. Sawing operations should only be performed outdoors. When power-sawing, wear goggles to protect eyes from flying particles.
If preservative or sawdust from preserved wood accumulates on clothes, launder before reuse. Launder work clothes separately from other clothing.
When the life of your preserved wood is done, either because it has become obsolete with new development or because it has fulfilled its life expectancy, it should be disposed of properly.
Try to recycle preserved wood if possible. Parks, farms and residential landscaping often can utilize recycled preserved wood for projects that are exposed in the outdoors.
Preserved wood should not be burned in open fires or in stoves, fireplaces or residential boilers because hazardous chemicals may be produced as part of the smoke and ashes. Preserved wood from commercial or industrial use (i.e. construction sites) may be burned only in commercial or industrial incinerators or boilers in accordance with state and federal regulations.
Preserved wood can be used in an industrial biofuel burner, if it is a permitted facility that can meet state and federal air quality standards. It is considered biomass in several states and may be eligible for renewable energy credits.
As a last resort, send it to a landfill. Preserved wood is not considered hazardous waste and can be disposed of normally into an approved landfill.
Specific regulations in disposing preserved wood are detailed in the publication Management of Used Treated Wood Products in the Western U.S.
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.
A new 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:
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