Be Careful with Pressure Treated Wood

Be Careful with Pressure Treated Wood

by Cathy Donohue

Environmental concerns about wood and wood products include where the wood is from-local woods or endangered woodlands, and how it's been harvested-clearcut or ecologically harvested. When it comes to your family's health and safety, add "what's it been treated with?" to the list.

Wood for outdoor projects, including decks, playsets, and railings, may be what's called "pressure treated." Pressure treated wood is wood that's been treated with a wood preservative to help protect it from insects and decay. Some pressure treated wood is treated with the pesticide chromated copper arsenic (CCA). This arsenic treated lumber is saturated with a solution containing 22% pure arsenic.

Arsenic is a poisonous naturally occurring element that humans have known is deadly for thousands of years. Arsenic's use as a pesticide has long been banned. Yet a 12 foot long, 2-inch by 6-inch board of arsenic treated lumber contains about an ounce of arsenic-enough to provide a lethal dose of arsenic to 250 adults. An area of arsenic treated lumber the size of a four-year-old's hand contains an average of 120 times the amount of arsenic the EPA allows in a 6-ounce glass of water, according to a sampling by the Environmental Working Group and Healthy Building Network.

According to the National Academy of Sciences, the health effects from arsenic exposure include skin lesions, cancers of the bladder, liver, kidney, lung, skin and nasal passages, as well as brain, heart, and lung disease, diabetes and reproductive problems. Exposure to arsenic is cumulative-it builds up in the body.

In February 2002, the Environmental Protection Agency announced that no CCA lumber will be sold for residential uses after December 31, 2003. But it's still being sold now, and with the spring building and home repair season upon us, it's important to know how to handle this product safely.

How can you tell if your deck or railing is arsenic treated lumber?

There's no sure way to tell if an existing structure is made from arsenic treated wood. Pressure treated lumber is typically tinted green, and it may be marked or tagged with the names of the chemicals used to treat it. The Vermont Public Interest Research Group (VPIRG) recommends that if you are unsure of the type of pressure treated wood, it's safest to assume it's been treated with arsenic.

How can you be exposed?

Arsenic dissolves readily in water. Rain, washing the deck, even wet feet and hands can leach the arsenic out of the wood into the soil below, or into the human body if bare skin comes in contact with the wood. Children's sweaty, sticky hands can increase arsenic rub off from structures, and they can ingest it when they put their hands in their mouths.

You can also be exposed while building structures with this material, and school shop classes sometimes use arsenic treated wood for projects like picnic tables or other outdoor structures.

What should I do if I come in contact with arsenic treated wood?

Wash your hands, feet-all skin that comes in contact with the wood-well with soap and water after touching or handling it. Wash children's hands after every exposure, especially before eating.

How should I treat existing pressure treated structures at my house?

You can either keep the structure until it's time to replace it, or remove it. If you keep it, you need to commit to sealing it at least once a year; VPIRG recommends sealing it twice a year. You can use a water-based sealant available at hardware stores, such as Bioshield, Miller Paint and AFM Safe Coat Paints. For decks and other structures with soil under them, be aware that the soil may be contaminated with arsenic that's leached out of the wood. The arsenic doesn't move more than a foot through the soil, but it never leaves either. Make that area off-limits to children and pets and don't store household items under arsenic treated structures. The soil can be bagged and disposed of with regular trash disposal in a lined landfill.

VPIRG also recommends that you develop a schedule for replacing the structure, since there's still a risk of arsenic exposure with sealed structures.

If you're planning a new structure at home, the District recommends you choose naturally rot resistant woods like white cedar, tamarack and hemlock, or manufactured products such as recycled steel, recycled plastic or concrete. For structures that come in contact with the soil, like a deck, put concrete pilings into the ground and attach the structure to it.

Arsenic treated wood is a real human health concern. But knowing how to treat it and developing a plan for its future removal can minimize exposure risks. Be aware of the potential uses of arsenic treated wood away from home as well. Picnic tables, playground structures at schools and parks, boardwalks, fences and more may be made from this wood.

The District supports the recommendations of the Vermont Public Interest Research Group on this issue. Please call our office with any questions and for more information-802-229-9383 or contact VPIRG at 223-5221. Thanks to VPIRG for much of the information included in this article.