Treated Wood Waste Disposal

Treated Wood Waste (TWW) comes from wood treated with chemical preservatives, often identified by green or dark brown coloring and staple marks. TWW may be used in decking, fence posts, landscape timbers and guardrails to name a few. Non-utility disposal of telephone poles and railroad ties is also prohibited.

Effective January 1st, 2021 Treated Wood Waste To Be Handled As Hazardous Waste

The statute (Health and Safety Code (HSC) 25150.7) and regulations (California Code of Regulations, title 22, section 67386.1 et seq.) that authorized treated wood waste (TWW) to be handled with alternative management standards will expire on December 31, 2020. After that date, all TWW that exhibits the hazardous waste characteristic of toxicity will be a fully regulated hazardous waste and will no longer be eligible for disposal in Class II or Class III landfills.  TWW generators are also required to use Hazardous Waste contractors to properly transport and dispose of TWW.

There are two main groups of treated wood preservatives, water-based and oil-based. Wood treated with water-based preservatives are widely used and are commonly utilized in residential, commercial, marine, agricultural, recreational, and industrial applications. Wood treated with oil-based preservatives is primarily used for industrial applications such as utility poles, piling, posts, and railroad ties.

TWW has the potential to be a hazardous waste if it contains elevated levels of one or more of the following constituents: arsenic, chromium, copper, pentachlorophenol, and creosote. If TWW is not properly disposed of, the chemicals it contains can contaminate soil, surface water, and groundwater. This poses a risk to human health and the environment. TWW may exceed California hazardous waste thresholds for non-RCRA waste; studies have shown that TWW is less likely to exceed U.S. EPA hazardous waste thresholds for RCRA waste.

In California, TWW that is a hazardous waste is identified as (State Hazardous Waste Code 614).