Overview

Treated wood contains chemical preservatives to protect it from water damage, fungal decay, and insect infestation. A cause for concern, however, is that one of the most common preservatives contains high levels of arsenic - a known carcinogen. This is the popular preservative Chromated Copper Arsenate (CCA). Arsenic also appears in several other preservatives, such as Ammoniacal Copper Arsenate and Ammoniacal Copper Zinc Arsenate, but CCA is the most widely used.

After twenty years of heavy consumer use of CCA, today questions are being raised about its potential health and environmental risks. High levels of arsenic have been found in soil samples taken from residential sites (around decks) where CCA-treated wood was used. For those working with the wood, there are additional concerns about risks of exposure. Disposal concerns have arisen because tests indicate that most of the arsenic remains in the wood after its useful life. These and other factors have led people to seek out alternatives, including recycled plastic lumber and wood that is treated with Ammoniacal Copper Quaternary (ACQ), a less-toxic chemical preservative.

The Environmental Protection Agency (EPA) has phased-out usage of woods treated with CCA. In spring 2002, the Environmental Protection Agency (EPA) announced a voluntary decision by industry to move consumer use of treated wood away from a variety of pressure-treated woods that contain arsenic by December 31, 2003. Today, existing stocks of CCA-treated wood may be sold until depleted, and consumers may still buy and use this old stock. But no new product will be sold for residential use. For more information, see the EPA's CCA Guidance page.

Before buying or using treated wood, consider where the wood will be used and investigate alternative materials. In a downloadable fact sheet, the Minnesota Pollution Control Agency recommends that homeowners consider several factors before buying treated wood. Anyone using treated wood should weigh these factors:

• Will the wood be used indoors or outdoors?
• Will people or animals come into direct contact with the wood?
• Will the wood come in contact with any drinking water source?
• Will the wood come in contact with any water body, such as a lake, stream, or ground water?
• Is there a less toxic or nontoxic alternative to using treated wood?

Alternative Materials

There are a variety of less toxic materials suitable for many projects as substitutes for treated wood. Some examples include:

• Metal for structural applications and plastic for docks, decks and other outdoor amenities. For more information, see Plastic Lumber.
• Untreated cedar in places where people come in direct contact with the material.
• Landscape blocks or rocks for landscaping projects.
• Steel pilings filled with concrete in place of creosote-treated underground construction pilings.
• Wood treated with less toxic preservatives, such as ACQ.

Laws & Guidelines

Minnesota businesses producing arsenic-treated wood waste (CCA) have been subject to hazardous waste rules which require them to determine if the waste is hazardous, using the Toxicity Characteristic Leaching Procedure (TCLP). If the waste is found to be hazardous, it must be disposed of at a hazardous waste incinerator or landfill and transported using a licensed hazardous waste transporter.

Performance

ACQ-treated wood contains no EPA-listed hazardous compounds. It meets the same standards for above-ground and ground contact established by the International Conference of Building Officials (ICBO) and American Wood Preservers Association (AWPA) for CCA-treated wood. According to Chemical Specialties, Inc., a manufacturer of the ACQ preservative, 99% of the preserved wood market could be served with ACQ-treated wood.

Availability

ACQ-treated wood is widely available at building centers in Minnesota. At this time, there is one Midwest area manufacturer producing ACQ-treated wood, Northern Crossarm Co., Inc., while others are appearing nationally.

Cost

Wood treated with ACQ typically costs 7% to 12% more to purchase than CCA-treated wood. However, savings can be realized by not having to manage wood waste that may fail the TCLP test and be determined hazardous. ACQ-treated scraps can be managed by much less expensive means: they may be placed in the regular trash, delivered to a lined solid waste landfill, or taken to a wood waste recycler for chipping. If taken to a recycler, be sure to call first and document that the wood was treated with ACQ.

Specifications

Any project calling for treated wood should include specifications that require ACQ-treated wood. Specifications should also require that the delivered product comply with the Uniform Building Code for wood preservative treatment and be identified with the ACQ Wood Preservative Treatment mark.

Vendors

Manufacturer
Northern Crossarm, Inc.
Chippewa Falls, WI
800/236-9663
fax: 715/723-0861
Product: ACQ Preserve treated wood. ACQ Preserve is widely available; contact Northern Crossarm for a current list of Minnesota distributors.

Other Vendors
A number of alternatives to CCA-treated wood exist, including non-CCA-treated wood, recycled plastic and composite lumber, and other materials. For links to manufacturers and products, visit the lumber products section of BANCCA.org.

Resources

Sources

MPCA Listed Metals Advisory Council
Meeting Minutes
March 24 and 25, 1999

MPCA
"Treated Wood: Use, Disposal and Alternatives for Homeowners", April 2002
"Treated Wood: Use, Disposal and Alternatives for Businesses", March 2000

John Ikeda
MPCA, 651/296-6300

Lloyd Petrie
MPCA 651/296-8585

"Arsenic and Old Waste"
This Old House
January 1997