Timber industry report says arsenic OK

3.00pm

The timber industry is staging a fightback against public perceptions of arsenic-treated timbers posing risks to homeowners, workers and children, by producing its own report "clearing" the timber treatment.

"Fears that arsenic in treated timber represent significant public health risks have been rubbished," said the president of the New Zealand Timber Industry Federation, John Hawkins.

"Two of Australasia's most prominent toxicologists have just released a report which unreservedly gives a clean bill of health to timber treated with a preservative including copper chrome and arsenic," he said in a statement.

The US Environmental Protection Agency (EPA) will from next January cancel the registration of arsenic treatments for wood used in most residential settings -- including play equipment, decks, picnic tables, landscaping, residential fencing and walkways.

The US consumer products safety commission has also assessed the health risk to children associated with arsenic-treated timber.

In May, the Government's watchdog on hazardous substances said it could not ban arsenic-treated wood from being used on children's play equipment and homeowners' decks, even though the United States was stopping its use.

The Environmental Risk Management Authority (Erma) said before it could ban copper chromium arsenic (CCA) as a timber treatment, legally it would have to trigger a reassessment of the chemical.

"Currently there is not sufficient evidence to demonstrate that the health risks associated with the current population's exposure to CCA-treated timber warrant the substance being reassessed," Erma said.

Instead, it proposed "prudent measures" to limit voluntary exposure to CCA and further investigation "into any environmental and occupational risks associated with the use of CCA".

The timber industry federation's report released today was compiled by Dr Peter di Marco, an Australian toxicologist, and Dr Wayne Temple, Director of the National Poisons Centre at Dunedin University, New Zealand.

The federation said it included findings from a recent visit by Dr Temple to the USA where he met Environmental Protection Agency staff and attended a conference which reviewed recent research.

The federation's report says "cancer risk estimates for CCA exposure are worst case hypothetical estimates and the true risk at low dose may be close to zero. Exposures to arsenic associated with CCA-treated wood in domestic and playground settings do not pose a significant health risk to children".

The Dominion Post newspaper earlier published results of its own research into arsenic contamination around timber playground equipment. The newspaper reported arsenic levels of up to 300mg/kg -- 10 times over Environment Ministry guidelines.

CCA timber treatments were "grandfathered" into the new regulatory regime under the Hazardous Substances and New Organisms Act 1996 (HSNO), but along with other pesticides are not due to be brought under the new rules until July 1 next year.

Arsenic, both manufactured and naturally occurring, can cause cancer and nerve, stomach, intestine and skin problems. Small levels can be contracted by touching treated wood or contaminated soil but there is conflicting data on the quantities required to affect humans.

The EPA began reviewing the risks from wood preservatives in 1978 and six years later issued worker protection guidelines, and requiring consumer warning labels on timber containing arsenic.

But a report by University of North Carolina scientist Rick Maas, which concluded that regular direct contact with CCA-treated timber was "a national health priority", prompted the EPA and timber companies to phase out by December 2003 wood deck and playset uses of arsenic-based preservative.

Since then, the US Consumer Products Safety Commission has reported arsenic exposure can lead to lung and bladder cancers.

The commission said toddlers who routinely put their hands in their mouths were ingesting significant quantities of arsenic when they used playground equipment made of arsenic-treated wood. Similar problems arise from arsenic-treated house decks.

A child's exposure varies according to how often and for how long they played on arsenic-treated timber, the amount of arsenic on their hands, and the amount of that which they swallowed.

The US report said the lag time between exposure to arsenic and cancer arising in a person could be decades, but the increased cancer risk would range from about two extra cases per million people to 100 extra cases.

The agency said not every exposed individual would get cancer, but to minimise the risk of exposure, children's hands should be washed with soap and water immediately after outdoor play and before eating.

- NZPA