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Treated Wood Waste

Treated Wood Waste

What is Treated Wood Waste (TWW)?

On August 31, 2021, Governor Newsom signed Assembly Bill 332 and the bill takes effect immediately. AB332 adopts new Alternative Management Standards (AMS) for treated wood waste that are codified in Health and Safety Code section 25230. As a result of the chaptering of the bill, all treated wood waste variances issued by DTSC since March 2021 are now inoperative and have no further effect. The variances are no longer necessary because they have been replaced by the AMS. The new AMS are similar to the rules that applied under the variance program, except that no variance is required.

The California Department of Toxic Substances Control defines treated wood waste (TWW) as wood that has been treated with chemical preservatives. These chemicals help protect the wood from insect attack and fungal decay while it’s being used. Fence posts, sill plates, landscape timbers, pilings, guardrails, decking and grape stakes are all examples of chemically treated wood.

Is TWW Toxic?

TWW contains hazardous chemicals that pose a risk to human health and the environment. Arsenic, chromium, copper, creosote and pentachlorophenol are among the chemicals used to preserve wood and are known to be toxic or carcinogenic. Harmful exposure to these chemicals may result from touching, inhaling or ingesting TWW particulate (e.g., sawdust and smoke).

    16411 Lamb Canyon Road, Beaumont, CA 92223
    Fee schedule:  Hard to Handle refuse disposal rates apply
    31125 Ironwood Avenue, Moreno Valley, CA 92557
    Fee schedule:  Hard to Handle refuse disposal rates apply
    10910 Dawson Canyon Road, Corona, CA 92883
    Visit for details.

    Fee schedule:  Hard to Handle refuse disposal rates apply

    • All customers with TWW must declare their load at the scale house (fee booth).
    • TWW is subject to the Hard-to-Handle tipping fee; therefore TWW must be separated from all other waste or the full load will be billed at the Hard-to-Handle rate.
    • The Department of Toxic Substances Control (DTSC) enforces the Alternative Management Standards (AMS), which include labeling, accumulation time limits, treatment, disposal, shipping document standards and employee training requirements.  For questions concerning AMS, generators of TWW should call the Department of Toxic Substances Control’s Regulatory Assistance Officers at (800) 728-6942, or (800) 72TOXIC. DTSC regulations for TWW can be found on their website at
    • A Bill of Lading is required to be completed by customers with TWW.  Complete the Bill of Lading prior to arrival at the landfill.
    • Due to landfill permit conditions, customers are encouraged to contact the Department at (951) 486-3200 in advance to confirm the acceptance of TWW for the day.

    Waste Guide

    How can I tell the difference between TWW and old wood?

    Treated wood is wood that has gone through a treatment process with chemical preservatives to protect it against pests and environmental conditions. Typically, treated wood is used in exterior applications where ground or water contact is likely.

    Treated wood can often be visually distinguished by its appearance. There are several signs to look out for when determining if a piece of wood has been treated or not. What are some things to look for when determining if wood is treated or not?

    • Treated wood end tag
    • Wood manufacturer stamp codes
    • Indentations on the surface of the wood
    • When cut, staining is visible around the perimeter only
    • Discoloration (e.g. green or dark brown appearance)
    • Odor

    Example of treated wood end tag.

    Example of wood manufacturer stamp codes.

    Example of pressure treated wood showing indentations from treatment.