Paints, Stains Can Minimize Arsenic Leaching From Wood
Posted August 19, 2002
RALEIGH, N.C. — Pressure-treated wood used to build decks, play sets and picnic tables could be leaching a dangerous chemical; however, there are some easy ways to protect your family.
Most of the wooden structures are made with wood treated with a pesticide called chromated copper arsenate or CCA.
Federal and state agencies government warn that the treated wood poses serious health risks because it can leach arsenic.
"What we know is that when rain penetrates the surface of the wood, it lifts the arsenic up to the surface," said Dr. Luanne Williams, a state toxicologist.
Children can then get the arsenic on their hands and put their hands in their mouths. Experts said it is not necessary to tear down existing decks or play sets.
Dr. Larry Jahn, a wood and paper science professor at North Carolina State University, said research shows common products minimize arsenic leaching.
"If you're concerned about the leaching of the pressure-treated material, the best thing you can do to reduce that is a paint, whether it's water-based or oil-based," he said.
Jahn said paint works best because it covers the wood, but he said that it is also difficult to maintain -- especially in high-traffic areas.
Jahn said semi-transparent stains are a better choice because they are easy to maintain, give wood long-lasting protection and reduce leaching.
"From a maintenance standpoint, you can use a semi-transparent stain and still reduce the amount of leaching," Jahn said.
None of the 30 stains
tested over the past six years held up that long, but two brands lasted four years. They are Cabot Decking Stain and Glidden Endurance Deck and Siding Oil Stain.
Jahn said clear water repellent will work, but must be reapplied every year.
He also warned that varnish should never be used outdoors because it cannot stand up to the elements and can chip and peel.