Managing Hazardous Waste

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Requirements for Generators of Treated Wood Waste (TWW) Fact Sheet

December 2008*

What is Treated Wood Waste (TWW)?

TWW is wood commonly used in ground or water contact applications that has been removed from service. This wood is typically treated with preserving chemicals that protect the wood from insect attack and fungal decay during its use. Examples include fence posts, sill plates, landscape timbers, pilings, guardrails, and decking.

What are the Health and Environmental Hazards?

TWW contains hazardous chemicals that pose a risk to human health and the environment. Arsenic, chromium, copper, creosote, and pentachlorophenol are among the chemicals added to preserve wood. These chemicals are known to be toxic or carcinogenic. Harmful exposure to these chemicals may result from dermal contact with TWW, or from inhalation or ingestion of TWW particulate (e.g., sawdust and smoke).

What are the Hazardous Waste/Alternative Management Standards (AMS)?

Because TWW contains hazardous chemicals, at elevated levels, it is subject to California’s Hazardous Waste Control Law. The Department of Toxic Substances Control (DTSC) has developed alternative management standards (AMS) for TWW that are based upon full hazardous waste requirements but are adjusted for the unique circumstances associated with TWW. The AMS is in California Code Regulations (Cal. Code Regs.) title 22, division 4.5, chapter 34. In summary, AMS lessen storage requirements, extend accumulation periods, allow shipments without a hazardous waste manifest and a hazardous waste hauler, and allow disposal at specific non-hazardous waste landfills. The AMS simplify and facilitate the safe and economical disposal of TWW. (Note -TWW that is removed from utility services or is a RCRA hazardous waste is not eligible for AMS.)

What are the Handling and Disposal Requirements for TWW?

The AMS, which went into effect on July 1, 2007, are intended to ease regulatory burdens. Although hazardous waste generators are required to properly classify their waste through knowledge or laboratory analysis, generators of TWW can presume their TWW is hazardous waste and avoid expensive laboratory testing. Generators can then manage their waste in accordance with the AMS, including disposal at certain non-hazardous waste landfills. Upon acceptance at these certain landfills, the TWW, at that point, becomes non-hazardous waste pursuant to Health and Safety Code section 25150.8. Specific generator requirements for households, small business, and all others are presented in the following sections:


Households typically generate TWW when a fence or deck is replaced. Under AMS, households must:

  1. Keep TWW segregated from other materials.
  2. Store less than 1,000 pounds of TWW for no more than 30 days following its removal from use.
  3. Transport TWW to an authorized TWW facility. If the TWW is going to a Household Hazardous Waste (HHW) Collection Center, call and confirm the acceptance of TWW (not all HHW Collection Centers handle treated wood waste or can only collect limited amounts).
  4. Identify TWW to TWW facility personnel.

It is important to note that the AMS also prohibit TWW from being burned, chipped, ground, or mulched. TWW stored for more than 30 days would invoke additional requirements on households that apply to businesses.

Businesses Generating TWW Incidental to the Normal Course of Business

Incidental generation occurs when a business generates TWW as a result of activities not associated with the business’s core operation. For example, a retail store, a doctor’s office, or an auto body repair shop might generate TWW when repairing or replacing signage or fencing at their place of business. This TWW is considered “incidentally generated” because these businesses are not routinely involved in construction, demolition, or other activities that involve treated wood. Under AMS, businesses that “incidentally” generate TWW can generally comply with handling and disposal requirements by:

  1. Keeping TWW segregated from other materials.
  2. Labeling all TWW bundle/shipments with the following information:

Treated Wood Waste - Treated Wood Waste - Do not burn or scavenge. Provide the following information: TWW Handler Name, Address, and Accumulation Date

  1. Storing no more than 1,000 pounds of TWW for no longer than 30 days. Incidental generators who store TWW for more than 30 days are subject to the additional requirements for businesses that are routine generators of TWW.
  2. Transporting TWW to an authorized TWW facility.
  3. Identifying TWW to TWW facility personnel.

Businesses Generating TWW during the Normal Course of Business

Businesses that generate, handle, or accumulate more than 1,000 pounds of TWW in 30 days engaged in activities expected to routinely generate or handle TWW, such as, construction/demolition contractors, and business and homeowners generating large quantities (i.e., accumulating more than 1,000 pounds in 30 days) must meet the requirements listed below. In complying with the TWW AMS, these businesses will minimize their liability concerns and eliminate possible future cleanup cost associated with mismanagement of TWW.

  1. Get prior confirmation that the solid waste facility or hazardous waste facility will accept TWW shipment. Not all facilities accept TWW, so check with the facility before transporting to ensure that their load will not be rejected. (Cal. Code Regs., tit. 22, § 67386.7(b)).
  2. Store TWW off the ground by placing it on blocks, on concrete surfaces, or in containers. Movement of large quantities of TWW can be facilitated by bailing and or palletizing TWW, which may also prevent ground contact. (Cal. Code Regs., tit. 22, § 67386.6(a)).
  3. Do not store TWW beyond the allowed limits (90 days – block and tarp, 180 days – containment pad, 1 year – container and storage building). (Cal. Code Regs., tit. 22, § 67386.6(a)(2)).
  4. Cover TWW during inclement weather to prevent rain water from leaching chemicals out of the TWW. (Cal. Code Regs., tit. 22, § 67386.6 (a)(2)).
  5. Accumulate TWW away from public access. (Cal. Code Regs., tit. 22, § 67386.6(a)(1)).
  6. Do not burn TWW. It is illegal to burn TWW without a hazardous waste permit. (Cal. Code Regs., tit. 22, § 67386.3(a)(1))
  7. Contact DTSC if planning to reuse the removed TWW to ensure compliance with existing hazardous waste laws. (Cal. Code Regs., tit. 22, § 67386.3(c)).
  8. Keep TWW from mixing with other waste. (Cal. Code Regs., tit. 22, § 67386.3(a)(3)).
  9. Label all TWW bundle/shipments with the following information (Cal. Code Regs., tit. 22, § 67386.5(b)):

Treated Wood Waste - Do not burn or scavenge. Provide the following information: TWW Handler Name, Address, and Accumulation Date

  1. Keep records for at least three years from date of shipment or receipt to demonstrate that TWW was properly managed. Records should include: (1) name and address of the TWW facility to which the TWW was sent; (2) estimated weight of TWW, or the weight of the TWW as measured by the receiving TWW facility; and (3) date of the shipment of TWW. (Cal. Code Regs., tit. 22, §§ 67386.8(a) and (e)(1)).
  2. Notify DTSC within 30 days if generating more than 10,000 pounds of TWW per calendar year. See the listings at the end of this fact sheet for the online notification web site.The following information must be submitted:
    1. Name and mailing address;
    2. Identification Number;
    3. Name and telephone number of the TWW contact person;
    4. Address or physical location of the TWW management activities;
    5. Date exceeding the 10,000 pound limit; and
    6. A statement indicating that the business is generating more than 10,000 pounds of TWW per calendar year. An Identification Number can be obtained by calling 1-800-618-6942. (Cal. Code Regs., tit. 22, § 67386.9).
  3. Arrange for shipment to a TWW facility. Disposal is allowed at a hazardous waste landfill or a qualified solid waste landfill. See the listings at the end of the fact sheet for information on facilities that have been authorized to accept TWW. Contact the TWW facility to obtain costs as they may be adjusted based upon volume. (Cal. Code Regs., tit. 22, § 67386.11).
  4. Train employees involved in TWW handling and keep the training records for three years. The training shall include applicable requirements of Cal/OSHA and regulations relating to hazardous waste, methods for identifying and segregating TWW, safe handling practices, requirements of AMS; and proper disposal methods. (Cal. Code Regs., tit. 22, § 67386.12(a)).

Frequently Asked Questions (FAQs)


Q: Does TWW need to be transported with a hazardous waste manifest or use a hazardous waste hauler?

A: No, you can transport TWW using a shipping document, bill of lading, or invoice as documentation and you can use any hauler to transport your TWW off-site.

What information needs to be provided to TWW facility personnel?

A: ID Number or site name, address, contact person’s name, phone, and mailing address.

Q: Can I reuse my TWW after its initial removal from service?

A: Yes, with the restriction that you use it on-site for its intended use and if you store it no longer than the allowed time limits.

Q: Am I allowed to cut TWW?

A: Yes, but solely for resizing to accommodate for shipping limitations. Any sawdust must be captured and managed as TWW.

Q: Is it possible that creosote treated wood waste becomes a hazardous waste?

A: Yes, a generator is required to properly classify the waste through knowledge or laboratory analyses.

Q: Am I charged the fees for generating TWW?

A: Yes, TWW is considered to be hazardous waste prior to the point of acceptance at authorized solid waste landfills and therefore is subject to generator fees. For further information, you can contact our Fees Unit at (916) 322-2448 or Environmental Fees Division of Board of Equalization at (916)-323-9555.

Q: What facilities are authorized to accept TWW?

A: See listings at the end of the fact sheet.

Treated Wood Waste Web Page Listings

The following items are found on our Treated Wood Waste web pages:

  • Final Regulations
  • Regulatory Background
  • Treated Wood Waste Tracking System (TWWTS)
  • Treated Wood Waste Online Notification Form
  • Permanent Identification Number Form
  • Treated Wood Waste Training Materials
  • Fact Sheets and Other Information on Treated Wood Waste
  • Sampling and Analysis Study of Treated Wood
  • List of Landfills That Accept Treated Wood Waste

More Information & Contacts

For all other information, please contact the DTSC Office nearest you. You can also contact our Regulatory Assistance Officers at:

Toll-Free in CA: 800-728-6942 or 800 72-TOXIC
Outside CA: 916-324-2439

For a list of all DTSC offices, go to our Office Address and Phone Numbers web page.


This fact sheet does not replace or supersede relevant statutes and regulations. The information contained in this fact sheet is based upon the statutes and regulations in effect as of the date of the fact sheet. Interested parties should keep apprised of subsequent changes to relevant statutes and regulations.