HWTR Dangerous Materials

My Watershed

Manage Treated Wood Waste

Demolition operators often must manage treated wood waste. To encourage its proper disposal, there are exemptions to the Dangerous Waste regulations from this waste stream.

Excluded categories of waste is at WAC 173-303-071 of the Dangerous Waste Regulations.

Outdoor and structural wood is preserved from deterioration and natural decay caused by insects, fungi, and marine borer worms by dipping, spraying, or pressure-treatment with pesticides.

Example of Arsenic Warning Label

This label and similar safety labels from the American Wood Preservers Institute are required for CCA treated wood.

Treated wood from commercial or industrial sites may be managed so that it is exempt from the dangerous waste regulations (see the next section). If not exempt, it needs to be designated, and if it is regulated then disposed as a dangerous waste.

Regulated treated wood wastes may be burned only in commercial or industrial incinerators or boilers in accordance with state and Federal regulations. Do not burn treated wood at the job site.

Arsenic and Chromium Treated Wood

Pentachlorophenol Treated Wood

Creosote Treated Wood

Treated Wood Waste Disposal

Pressure-treating provides much longer lasting protection to exposed wood. Surface protection with pesticides is used to protect wood from sap staining, generally by dipping or spraying.

Most preserved wood was used for the following purposes according to the 1988 Federal Register Vol. 53, No. 251 pg. 53286:

  1. Lumber and timber, mostly preserved with inorganic arsenic and chromium formulations
  2. Railroad crossties, switch ties, and bridge ties, almost all preserved with creosote
  3. Poles, 60% preserved with pentachlorophenol, 23% preserved with creosote, and 17% preserved with inorganic preservatives.
  4. Fence posts, pilings, plywood, crossarms, and other products, mostly preserved with inorganics.

No one can tell if wood has dangerous levels of pesticides by looking at it. Generally, wood waste from commercial (non-homeowner) sites must be designated or evaluated to see if it is dangerous waste before it is disposed.

Related information

Focus on Treated Wood Exclusion is an Ecology publication that clarifies the disposal and recycling options for arsenic-, pentachlorophenol-, and creosote-treated wood.