discontinued use of CCA in & around homes

by Keith Loveridge

New regulations introduced in 2004, are listed below.

The use of CCA treated timber in retaining walls, skirting boards, tomato and grape stakes, decks, railings and boardwalks in marine environments, has now been disallowed. There is also a ban on importing and exporting CCA timber used in domestic areas. Other prohibited uses include:

Roof decking, studs, decking exposed to weather, flooring, sawn posts and columns supporting decks; posts, square fence, light fencing slats, pickets; landscape ties (sawn on all 4 sides), steps for trailer homes, wood wedges to support trailer homes, horse trailer, cattle trailer, trailers constructed of dimensional lumber.

It appears that domestic fencing has now been included in the list, which is interesting, because after the Canberra bush fires, the authorities had to remove many tonnes of contaminated ash due to the domestic CCA treated fencing that had burnt down. An Australian study has found that dioxins and furans are present in CCA ash (Environmental Science & Technology #37 pages 4148-4156).

The APVMA are still struggling with the issue here, in spite of stating categorically in July 2003 that CCA timber would be banned from certain domestic situations by December 2003. It is now July 2004 and it is still very quiet in Canberra. We have asked the Minister for an explanation of the long delay and have been told that correspondence is on the way. Meanwhile, children continue to be unnecessarily exposed to arsenic, chromium and copper.

U.S. Environmental Protection Agency – http://www.epa.gov

CCA Guidance – Questions and Answers – June 17, 2004

As of December 31, 2003, wood intended to be used in residential settings cannot be treated with chromated copper arsenate (CCA). Existing stocks of the wood may be sold by retailers until such stocks are exhausted, and consumers may continue to buy and use the wood for as long as it is available. In order to ensure clear guidance to wood treaters and others on what uses of CCA are allowed and what uses are discontinued, EPA has prepared this guidance document to ensure that CCA is being used consistently with the terms of the December 31st phase-out. Since there are so many types of dimensional lumber with a variety of uses, it is important to provide clear, easy-to-understand, and consistent guidance for the uses that can continue. Similarly, it is also important to specifically identify the types of wood that can no longer be treated with CCA products.

4. What is the Agency’s position on the use of CCA to treat wood used in the construction of residential retaining walls?

As of December 31, 2003, CCA cannot be used to treat wood that will be used in the construction of retaining walls in residential settings. The Agency has concern about the possibility of such treated wood being used in the residential market and the resulting potential for exposure. There are a number of alternatives to CCA-treated wood currently available on the market for use in retaining walls, including other wood preservatives, such as ACQ and copper azole, as well as durable woods such as western red cedar, yellow cypress, eastern white cedar, and redwood, and alternatives to lumber, such as synthetic materials and wood composites.

5. What is the Agency’s position on the use of CCA to treat skirtboards and sillplates used in the post-frame construction industry?

As of December 31, 2003, CCA cannot be used to treat wood for skirtboards and sillplates in post-frame construction. The Agency has concerns about the possibility of this size dimensional lumber being diverted to the residential uses where the potential for exposure exists. Dimensional lumber is characterized as having the following measurements: two inches up to, but not including, five inches thick, and two or more inches wide (e.g., 2″ x 4″). There are a number of alternatives to CCA for this particular use currently available on the market (see Question 4 for examples of such alternatives).

6. What other clarifications are included in the guidance document?

Clarification on a number of instances where CCA cannot be used to treat wood used on farms have also been included, such as wooden tomato stakes and wooden grape stakes.

8. Does this guidance change any uses of CCA to treat wood for marine (salt water or brackish water) use?

Yes, recently the registrants have agreed to voluntary cancel the use of CCA under the marine use standard, AWPA Standard C18, effective December 31, 2004. This standard refers specifically to “members out of water and not subject to salt water splash and not in soil use.” This means that CCA will not be allowed to be used to treat wood for marine construction on decking, railings, and boardwalks effective December 31, 2004. EPA will publish this label amendment for public comment. Furthermore, it is acceptable to use CCA to treat wood for marine construction in salt water or brackish water, for such things as pilings and submerged crossbracing.

9. What are the restrictions on exporting and importing CCA-treated wood?

As of December 31, 2003, it is illegal to treat wood with CCA for any prohibited residential use, including wood imported to be used domestically or exported for use in other countries. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

And here is research from Australia demonstrating the formation of dioxins and furans from fires of CCA treated timber

Environ Sci Technol. 2003 Sep 15;37(18):4148-56.

Assessing influence of experimental parameters on formation of PCDD/F from ash derived from fires of CCA-treated wood.
Tame NW, Dlugogorski BZ, Kennedy EM.

Process Safety and Environment Protection Group, School of Engineering, The University of Newcastle, Callaghan, New South Wales 2308, Australia.

Ash residues from fires of radiata pine timber, both untreated and treated with chromated copper arsenate (CCA), were analyzed for the presence of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/F). Fire conditions were simulated using a cone calorimeter. The sensitivity of the magnitude and profile of PCDD/F in the ash under controlled experimental conditions were examined to gain an insight into the formation of PCDD/F in a system containing CCA. The total amount of PCDD/F increased from 2.0 ng/kg of ash (0.05 ng of TE/kg of ash, using WHO-TEF) for untreated radiata pine to a maximum of 2700 ng/kg of ash (78 ng of TE/kg of ash) for 0.94% CCA. Ash containing CCA showed a distinct preference for formation of PCDFs, particularly the tetrachloro homologue. It is concluded that PCDD/F formation predominantly occurred via de novo synthesis during smoldering of the char rather than during the initial flaming and pyrolysis. Furthermore, the composition of the CCA constituents present in the timber was controlled to assess whether the physical presence of Cu, a known catalyst in PCDD/F production, was sufficient to account for the formation of PCDD/F in fires of timber impregnated with CCA.

PMID: 14524447 [PubMed – indexed for MEDLINE]