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.
California Governor Gavin Newsom signed Assembly Bill 332 into law on Aug. 31, 2021 after it was approved unanimously by the California Legislature. The bill had an urgency clause, permitting it to go into effect immediately. AB 332 statutorily incorporates the former Alternative Management Standards (AMS) for Treated Wood Waste, which allowed preservative treated wood waste to be disposed in the composite lined portion of an approved solid waste landfill.
The AMS had been in effect for nearly 15 years before the program expired on Jan. 1, 2021, creating significant difficulties for everyone needing to dispose of preserved wood. As a result, for the first three months of 2021, the disposal of treated wood was only authorized at a hazardous waste landfill. In March, the California Dept. of Toxic Substance Control (DTSC) created a variance program where those disposing of treated wood could purchase variances allowing disposal in approved composite-lined landfills per the provisions of the AMS.
With the adoption of AB 332, all treated wood waste variances become inoperative and are no longer in effect. However, this should not be an issue as the new law creates more disposal options with previously approved handling provisions.
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