Arsenic timber treatments chemical review

The APVMA reviewed arsenic-based timber treatments following concerns about the health of people coming into contact with the arsenic in treated timber structures.

In March 2003, the APVMA announced its decision to review the registration of timber treatment products containing arsenic. Arsenic timber treatments were nominated for review because of information that suggested that arsenic might leach out of treated timber and pose a risk to people and the environment.

In December 2003, the APVMA released the Arsenic timber treatments preliminary review findings report for public comment. In the preliminary review, the APVMA looked at a variety of issues related to the protection of the environment, worker safety and residues in commodities.

The APVMA considered all of the information available, including submitted data, public submissions and advice from the APVMA’s advisory agencies (the Australian Government departments responsible for health and the environment). The APVMA proposed that:

• to protect timber treatment workers and the environment, CCA product labels should be amended to include more detailed instructions for timber treatment operations, waste management and disposal
• CCA timber treatment products should be declared to be restricted chemical products
• supply and use of CCA timber treatment products should be restricted to authorised persons
• registrations and approvals for arsenic trioxide products could continue as before.

In March 2005, the APVMA released the Arsenic timber treatments review final report. The APVMA found that there could possibly be a health risk for people, particularly children, who had frequent and close exposure to CCA-treated timber, such as decks, garden furniture and playground structures. The APVMA cancelled the use of CCA for treating timber destined to come into frequent contact with people. Timber treated with CCA must now be clearly labelled as such and can only be used in situations in which people will not come into regular contact with it.

However, there was no evidence to justify cancelling the use of CCA to treat timber for materials such as telegraph poles, fence posts, fence palings or structural timbers, with which frequent contact is unlikely. For those uses, the levels of exposure, and hence the health risks, are low.

In the final review, the APVMA recommended:

• cancelling the use of CCA in situations in which people might come into frequent contact with the treated timber (such as timber used in garden furniture, picnic tables, exterior seating, children’s play equipment, patio and domestic decking, and handrails)
• permitting the continued use of CCA to treat timber in situations in which there would not be frequent and intimate contact with people (such as power and telegraph poles, fencing, structural timber in buildings, and so on)
• varying product labels to include more detailed instructions for timber treatment operations, including waste management and disposal and protection of the environment
• requiring that timber treated with CCA be clearly identified.

New rules for treating timber with CCA came into force from 1 July 2012. From that date, CCA products became restricted chemical products, which means that CCA can only be supplied to and used by suitably trained persons authorised under state or territory law.

Information on appropriate standards and training requirements is available.

The APVMA has the authority to regulate CCA products used to treat timber but does not have the power to control how people use structures made from the timber.

Use patterns for arsenic trioxide were determined to present a low risk to public health. Only trained, authorised pest control operators can use arsenic trioxide, and the areas of treated timber are concealed. Arsenic trioxide used correctly should not cause harmful effects to people, as the treated areas of timber are covered after application.