News Coverage
Arsenic on treated wood can linger for years, study finds
Published August 29, 2002
The amount of arsenic found on the surface of pressure-treated lumber used widely for decks and play sets exceeds safe levels even after years of wear, raising new concerns about health risks to children, a U.S. environmental group says.
The Environmental Working Group says that random tests on several hundred decks, play sets and other equipment conducted in 45 states showed that older structures contain just as much of the arsenic on wood surfaces as does newly treated wood.
In February, lumber companies, in an agreement with the U.S. Environmental Protection Agency, said they would phase out the use of an arsenic-based preservative in pressure treated wood. They said that after December, 2003, they no longer would use chromated copper arsenate, or CCA, a powerful pesticide, to protect lumber from decay and insect damage. But the EPA as part of the agreement also said it did not believe there was any reason for people to replace the CCA-treated wood, which is used in an estimated 90 per cent of all outdoor wooden structures such as decks, play sets and picnic tables in the U.S.
About 80 per cent of treated wood in Canada is treated with CCA, and that wood is used in playgrounds, backyard fences and decks. Waterfront structures, utility poles and highway sound barriers are also CCA-treated.
Arsenic is known to cause cancer and has been at the centre of a long-standing dispute over how much of it should be allowed in drinking water. The new study claims that "wipe tests" on the wood surfaces in many samples produced three to 10 times the arsenic now allowed in drinking water.
Toronto City Council decided last month that playground structures made of arsenic-laced pressure-treated wood are not so dangerous that they require immediate action.
The city used sealant on one High Park structure after The Star reported in May that nearby soil tests showed arsenic levels 15 times higher than federal safety guidelines of 12 milligrams per kilogram.
Council, however, held off on sealing some 260 other play structures, pending tests results expected by November on at least 82 sites.
The council debate revolved around the wisdom of spending $300,000 or more to apply penetrating oil-based sealant to playground equipment when tests may show it is not necessary. The tests are expected to cost about $90,000.
At the same time, the public health department has issued a "fact sheet" advising citizens to seal decks or play equipment made of pressure-treated wood, and to reapply sealant every one or two years.
The Star reported in February that the Canadian government was re-evaluating the safety of chemicals used in pressure-treated lumber and focusing on the cancer risks posed to children by the wood.
A spokesperson for Canada's Pest Management Regulatory Agency, which administers the Pest Control Products Act for the federal health department, said at the time: "We're in negotiations with the Canadian (pressure-treated lumber) industry, just as the Americans are with the American industry, but it's still too early to release details on that."
EPA spokesperson Steffanie Bell said the agency had not reviewed the Environmental Working Group's results and planned its own formal risk assessment next year.
"Right now we don't have any indication that (the wood) poses an unreasonable risk to the public, but we need to get additional information," Bell said.
Jane Houlihan, research director for the Environmental Working Group, said tests in 263 households showed that arsenic on the wood surface often exceeded the EPA's arsenic standard for drinking water, no matter how old the lumber.
"There's no question that kids are ingesting it," Houlihan said in an interview, because children routinely touch the wood and then put their fingers into their mouths.
In about one-quarter of the samples, the amount of arsenic wiped off the wood surface was at least three times the 10 micrograms that is the most allowed in a litre of drinking water under a new EPA standard. In some samples, the amount - collected from an area about size of a child's two hands - was up to 250 micrograms, the group said.
Structures more than 20 years old and less than a year old showed similar results, the report found. Deck sealant appeared to reduce surface arsenic levels for about six months but then made little, if any, difference.
The group did not recommend people take the costly step of replacing their decks but said they could seal the wood every six months, replace high-exposure sections with another type of wood, have children wash their hands after playing, or cover picnic tables with a tablecloth before using.
The U.S. wood preservative industry cited past statements by physicians that the CCA-treated wood has never been linked to skin disease or cancer in children although it has been used for decades. The industry says such wood is safe when used properly.