Arsenic Based Timber Treatments - frequently asked questions

Updated: 30 March 2006

What is the Australian Pesticides and Veterinary Medicines Authority (APVMA)?

The APVMA is the Australian Government statutory authority responsible for the regulation of pesticides and veterinary medicines up to the point of retail sale.

All pesticides and veterinary medicines must be registered by the APVMA prior to being supplied, sold or used throughout Australia.

Pesticides include products that are used around the home garden and those used for commercial or agricultural purposes.

What is product registration?

Registration means that the pesticide or veterinary medicine has been rigorously assessed to ensure that it works, is safe for people, animals and the environment, has been manufactured to appropriate standards and does not pose an unacceptable risk to Australia’s trade with other countries.

All registered products have an approved label that includes instructions for correct use and relevant safety information. Only registered products have a distinguishing number on the label APVMA Approval no. xxxxx/ or NRA Approval No. xxxxx/.

What is a chemical review?

The APVMA has a program for reconsidering (reviewing) the registration of older chemicals that are currently on the market. Reviews are undertaken when there is new information that raises potential concerns about a chemicals ongoing use, suggesting that its registration should be reassessed. This is the process which has been undertaken for arsenic-based timber treatment products.

Reviews can be triggered by new research or other evidence that has raised concerns about one or more of the following:

the safety of people using the chemical or the product;
an effect that is harmful to public health;
an unintended effect that is harmful to animals, plants or to the environment;
a prejudice to trade or commerce between Australia and places outside Australia;
whether the product is effective when used as instructed by the label; and
labels instructions for the safe and effective use of the product.

When the APVMA decides to reconsider the registration of a chemical it will call for any relevant new information from registrants and the public. It may also require registrants to conduct new studies. The APVMA then assesses all the information and publishes a review report that details its findings. The assessment also forms the basis for decision about the future availability of the chemical or how it is used.

There are three possible outcomes from a review:

The APVMA is satisfied that products are safe and effective and chemical use can continue based on existing instructions;
The APVMA has identified that some aspect of the chemical or its use may not be safe and therefore makes changes to the conditions of registration and/or the label instructions; or
The APVMA is not satisfied that continued use of the chemicals will be safe and effective and suspends or cancels the chemical.

What are arsenic based timber treatments and how are they used?

There are two main arsenic based timber treatment products, copper chrome arsenate (CCA) and arsenic trioxide. These products are chemical preservatives used to protect wood from rotting and being attacked by fungus, termites, or other wood-boring insects.

In Australia, CCA treatments are primarily used on pine. Without CCA treatment, pine used in the ground could rot in less than 12 months. CCA treatment protects pine for as long as 20 years.

CCA timber treatments have been used for over 60 years around the world, and have been registered in Australia for more than 20 years.

Arsenic trioxide is used by pest controllers for treatment of termites around buildings.

What is CCA treated timber used for?

CCA is largely used to treat timber intended for outdoor uses such as home, school, and community playgrounds, decks, and landscape timbers. CCA treated timber is also used in building structures and other non-domestic uses such as telegraph and electricity poles.

How can I tell if a timber structure has been manufactured from material treated with arsenic based products?

Wood that is freshly treated with CCA has a greenish tint, which fades over time. However, some other wood treatments may also have a green colour. Generally, unless your deck has been constructed with hardwood or cedar, it is possible that the deck was constructed with CCA-treated wood.

If you know who the building contractor or wood retailer was, you may want to call and ask.

As an outcome of the APVMA review, it is a requirement for all CCA-treated timber to be branded with the words ‘Treated with copper chrome arsenate’, up to point of first use.

Are there alternatives to arsenic based timber treatments?

There are arsenic-free alternative timber treatment products that are registered for use in Australia. These products control a similar range of pests.

Why did the APVMA review arsenic based timber treatments?

Arsenic timber treatment products were put under review in 2003. This followed new information, both from Australia and overseas, which highlighted public health concerns for human exposure to arsenic from treated timber structures. This was of particular concern where there is likely to be frequent and intimate contact by children.

A key issue was whether or not arsenic leaches from treated timbers and whether this might be likely to have an adverse impact on people and the environment.

How was the review conducted?

In undertaking the review the APVMA received information from a number of sources including scientific data packages submitted by registrants, submissions received from the public, published literature and international reports. Public submissions were received from a wide spectrum of the community, including individuals, relevant State and Territory departments, the CSIRO, environmental groups and timber industry groups.

Concerns raised through the public consultation process included the potential impacts on human health, possible modes of exposure, potential effects on the environment, the availability of suitable alternatives and potential impacts on business.

During the review, the APVMA consulted extensively with the registrants, representatives of the timber industry and state environment and agriculture departments. The APVMA also conferred with community representatives.

In evaluating the information, the APVMA received advice from the Office of Chemical Safety in the Department of Health and Ageing, the Department of the Environment and Heritage, and the then National Occupation Health and Safety Commission. Advice was also received from State/Territory government agencies. This advice was considered in preparing the recommendations of the review.

The APVMA released its Final Review Report (The Reconsideration of Registrations of Arsenic Timber Treatment Products (CCA and arsenic trioxide) and Their Associated Labels) in March 2005; this report details the regulatory arrangements for the future use of arsenic based timber treatments.

What did the APVMA find in its review?

CCA

From its assessment of the information available, the APVMA concluded that it had insufficient information to be satisfied that the continuing use of CCA is safe for timber used in structures with which the general community (and particularly children) are likely to come into frequent and intimate contact.

The review also found that product label instructions for timber treatment operations, waste management and disposal and protection of the environment were inadequate.

Therefore, the use of CCA for treatment of timbers for some end uses is to be phased-out. For remaining uses, however, the APVMA is satisfied, that by placing greater control on the use of CCA products, they can continue to be used safely. To achieve this, CCA product labels are being varied to:

require that timber treatment facilities be designed and operated to meet appropriate Australian Standards;
specify the circumstances in which CCA products can be used, and to prohibit uses of CCA for timber used in garden furniture, picnic tables, exterior seating, children’s play equipment, patio and domestic decking, and handrails;
require that timber be clearly identified as having been treated with CCA;
include more detailed instructions for timber treatment operations, waste management and disposal and protection of the environment.

While the review focused on public health and environmental issues, some questions relating to occupational health and safety risks were raised. As a result, the review report recommended that product registrants provide worker exposure studies for arsenic and chromium so that the adequacy of the instructions for use of the product and safety directions can be assessed.

Arsenic trioxide

For arsenic trioxide, which is used for termite control around buildings, no additional restrictions are proposed.

When will these new requirements take effect?

Some timber treatment plants may not be able to comply with the requirements of the approved labels until they make modifications to their operational processes and to their physical facilities. As a result, the APVMA issued a permit to allow time up to 11 March 2006 for the treatment plants to make the necessary modifications to their operational processes and their physical facilities and implement the new requirements. Just prior to this date, the permit was extended by three months until 7 June 2006. While most treatment plants have responded to the review requirements (ie. stamping the timber and not treating timber intended for the prohibited uses after the end of the original permit period of 11 March 2006), the APVMA was aware that a limited number of plants would not be fully compliant by this date. Therefore a short extension of the permit period was granted to enable these plants to make the necessary changes and to give States/Territories sufficient time to complete any legislative and/or administrative arrangements necessary to help oversee the controls on the use of CCA timber-treatment products.

How will these new requirements be put into effect?

The implementation of the review recommendations for CCA products is being augmented through the supporting activities of a number of other authorities. These include State and local government authorities, Standards Australia & New Zealand and the Australian Building Codes Board. The APVMA has consulted with these organisations to implement the proposed control measures recommended by the review, as follows:

a) Standards Australia & New Zealand: recent amendments reflect the fact that CCA timber-treatment chemicals are now prohibited for certain applications.
b) Local government and other planning authorities: recommended enforcement of Building Codes through building permits and inspections;
c) State EPA or other government / local government agencies responsible for inspection of treatment plants: oversight of compliance with labels and specified standards;
d) Parks & Wildlife, Environment, Education and other relevant agencies, Australian Local Government Association: recommended adoption of the end-use restrictions for CCA treated timber, including picnic tables and playground equipment.

Why has the APVMA made these recommendations?

The APVMA made these recommendations to ensure that the continuing use of arsenic based timber treatment products does not present a risk to public health and safety, or to the environment.

In particular, the decision to stop the future use of CCA treatment for timber used in structures such as childrens' play equipment and in decking provides a high level of protection for public health. For all chemical products it registers or reconsiders, the APVMA requires a high standard of scientific evidence supporting safe use before such uses can be permitted.

What uses are involved in the review recommendations?

Uses of CCA timber-treatment products that are not permitted include are for timber used in garden furniture, picnic tables, exterior seating, children’s play equipment, patio and domestic decking, and handrails.

Use will continue to be permitted where frequent and intimate contact with people does not occur. These include for power and telegraph poles, fencing, building structural uses where there is not frequent contact, and many other uses.

Should existing structures that have been treated with arsenic products be dismantled?

Various stakeholders have sought advice from the APVMA on the safety of existing CCA treated structures, particularly children’s playground equipment.

The APVMA has no regulatory authority over existing structures constructed of CCA treated timber and so has made no recommendation with respect to future action for existing structures.

However, the APVMA has consulted with agencies that have responsibility for existing structures and is making all scientific information available from the review available to them. This has assisted them in making their own risk management decisions.

The APVMA continues to keep abreast of overseas developments and, if any new information emerges relevant to the safety of existing structures, the APVMA will inform relevant authorities to enable any necessary actions to be undertaken.

To date, regulatory authorities in the USA, Europe and Canada have not recommended dismantling existing structures. However, the APVMA is aware that the USEPA is conducting an extensive assessment of this issue.

What can I do to decrease my child’s exposure to arsenic?

Trace amounts of arsenic are commonly found in the environment, in foods and in drinking water. The World Health Organization has set a tolerable daily intake for this natural element.

Regular exposure to certain uses of CCA treated timber may add an additional level of exposure to arsenic. Children can be exposed to arsenic from playground equipment primarily through hand-to-mouth contact when they touch the wood and then place their hands in their mouths. However, arsenic is not readily absorbed through the skin.

As always, parents should manage risks to their children and follow basic good hygiene practices.

Do not put food in direct contact with treated wood, for example, when eating from picnic tables.

Will painting arsenic treated timber reduce the risk of arsenic leaching to the surface?

Information is limited on the possible benefits of painting treated-timber (including existing structures) to reduce possible risks. Some scientific studies indicate that certain penetrating coatings, such as oil-based semi-transparent stains, when used on a regular basis may reduce the potential for CCA exposure. However, there have been some questions raised about the effectiveness of film-forming or non-penetrating stains because of cracking, peeling and flaking.

The USEPA is currently investigating the effectiveness of painting CCA treated timber structures. However the APVMA cannot provide any definitive advice at this time on whether there are benefits from painting.

Further information on this issue can be found on the USEPA website:

http://www.epa.gov/scipoly/sap/.
http://www.epa.gov/pesticides/.

What about arsenic leaching from landscape timbers into the vegetable patch?

Arsenic may leach from treated timber into soil, although this is very variable depending on a number of factors. Uptake of arsenic by plants is also variable depending on several factors.

The review assessments concluded that with leaching into the soil, in most situations the affected zone of soil is likely to be very limited, and plants growing near CCA treated posts did not have elevated levels of arsenic.

A precaution that could be taken is to insert a plastic liner between the soil and the timber.

Has the APVMA given consideration to community concerns in the review?

There has been considerable community interest in the review, particularly with regard to concerns over exposure of children.

The APVMA consulted extensively with the APVMA Community Consultation Committee and other members of the community when conducting the review. All submissions received during the public consultation period were considered in the final report.

What is happening overseas?

In the United States, the USEPA has facilitated voluntary phase-out of CCA-treated timber for use in domestic situations. It has not recommended the removal of any existing CCA-treated structures. The USEPA is conducting a probabilistic risk assessment for children who come into contact with CCA-treated play equipment and decks. While a draft preliminary risk assessment is available.

(http://www.epa.gov/scipoly/sap/2003/dec3/dec35meetingminutes.pdf), a final assessment is yet to be completed. The assessment focuses on arsenic exposure for children from decking and play equipment, and from direct ingestion of soil under and near decks and play equipment. This probabilistic risk assessment might help clarify the risk from the existing CCA-treated timber structures in the USA.
Another study underway by the USEPA is examining the effect of timber coatings as a level of protection from dislodgeable arsenic in existing CCA-treated structures. The final report) may provide helpful information. At this stage, only an interim report dated May 2005 has been posted on their website (http://www.epa.gov/oppad001/reregistration/cca/index.htm#sealants).

In March 2004, the USEPA released a preliminary risk assessment for human and environmental risks from wood preservatives containing arsenic and / or chromium for public comment. The human risk assessment related only to occupational exposure scenarios. The report related to the re-registration eligibility determination underway for CCA.

Canadian regulatory authorities are working in collaboration with the USEPA to effect similar actions in Canada. In particular, the regulator has also granted the voluntary cancellation of almost all residential uses of CCA. Permitted uses of affected products ceased in December 2003.

The EU issued a directive to Member States to stop use by 30 June 2004 of CCA-treated timber in residential constructions where people would be likely to have direct skin contact with the treated wood. This directive does not apply to CCA-treated wood already in use.

New Zealand regulatory authorities have determined that there was insufficient evidence at this stage to conclude that these products pose an unacceptable risk, but did support a move away from using CCA treated timber on children’s playground equipment.

To date no overseas regulator has required the demolition of CCA treated structures.

Where can I get a copy of the Final Review Report?

A copy of the Final Review Report can be found on the APVMA website.

The APVMA Chemical Review Team can be contacted as follows:
Chemical Review Team
Australian Pesticides and Veterinary Medicines Authority
PO Box E240
KINGSTON ACT 2604
Australia
Email: chemrev@apvma.gov.au
APVMA web site: http://www.apvma.gov.au