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Organic Alternatives to Treated Lumber |
| By Lance E. Gegner NCAT Agriculture Specialist Published 2002 ATTRA Publication #CT170 |
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Abstract
Treated lumber is not allowed under the Final Rule of the National Organic Program (NOP). This publication provides information on alternative products, including untreated lumber, alternatively treated lumber, alternative plywood products, and untreated fence posts. Table of Contents
IntroductionThis publication reminds all prospective and currently certified organic producers that treated lumber is not allowed under the Final Rule of the National Organic Program (NOP), and provides information on alternative products. For posts and lumber that are in contact with soil, crops, or livestock, the options include untreated lumber, alternatively treated lumber, alternative plywood products, and untreated fence posts. There are also wood treatments that can improve the lifespan of the materials by making them resistant to attacks by insects, fungi, and bacteria that cause deterioration and rot in unprotected wood. Producers will need to work with their organic certifiers to determine which alternative products or treatments are allowed and will work best for their specific operations. For a list of accredited certifying agents, visit www.ams.usda.gov/nop/CertifyingAgents/Accredited.html.
What is Used in Treated Lumber?Most treated lumber is preserved with creosote, pentachlorophenol, or chromated copper arsenate. Creosote, a brownish-black oil composed of hundreds of organic compounds and made from coal tar, wood, or petroleum, is a restricted-use pesticide that can volatilize into the air during hot weather, as well as leach into the soil. (Hoffman et al., 1995; Public Health Seattle & King County, 2000) Pentachlorophenol (PCP) is a member of the same chemical family as 2,4,5T, and can contain dioxins. Creosote- and PCP-treated woods are mainly used for railroad ties and telephone poles. They should never be used in enclosed areas. (MacMillen, 1995; Public Health Seattle & King County, 2000) Chromated copper arsenate (CCA) is used in the treated wood—often referred to as “pressure-treated lumber”—most commonly available in retail outlets. (Stehouwer, 2001) The CCA mixture, which contains copper, arsenic, and chromium compounds, is dissolved in ammonia and then forced, under high pressure, deep into the wood. (Hoffman et al., 1995) According to recent studies, arsenic can be absorbed through the skin on contact with treated wood. (Williams, 2002) The results of prolonged exposure to arsenic can include vomiting, diarrhea, nerve damage, blood vessel damage, and heart rhythm dysfunction. (Rodale, 2000) Arsenic is also an extremely potent carcinogen, and chromium is a suspected carcinogen. (Anon, 2001/2002) CCA-treated wood is resistant to leaching. However, arsenic, chromium, and copper do leach from the wood. Arsenic can collect in the soil under most CCA-treated wood applications. A 2" x 6" x 12' CCA-treated timber contains an ounce of arsenic; a utility pole can contain 40 pounds of arsenic. Burning the CCA-treated wood volatilizes some of the arsenic, but the ash remaining is technically a hazardous waste. Disposal of CCA-treated wood to landfills may be potentially dangerous because as the wood rots in the landfills the metals are released and may pose a threat to groundwater. (Quarles, 2002) The U.S. Environmental Protection Agency (EPA) has classified CCA as a restricted-use pesticide, but in the past did not restrict the use of CCA-treated wood. (Stehouwer, 2001) However, the EPA recently announced that CCA-treated lumber will not be allowed for residential use after December 2003. (EPA, 2002) Additional information on CCA is available from the EPA in their publication Chromated Copper Arsenate (CCA) and Its Use as a Wood Preservative available at www.epa.gov/oppad001/reregistration/cca/. USDA RegulationsThe Final Rule of the National Organic Program (NOP) declares that “a producer must not use lumber treated with arsenate or other prohibited materials for new installations or replacement purposes in contact with soil or livestock” (§205.206(f)). This restriction addresses applications such as:
Treated-lumber uses that are isolated from organic production—such as wooden building materials that are not in direct contact with either livestock or crops—are not restricted. The Final Rule of the NOP states:
Have any production-isolated uses of treated lumber documented in your Organic Production and Handling System Plan, an outline for which will probably be included in the application packet provided by the certifying agency. The ATTRA publication Creating an Organic Production and Handling System Plan: A Guide to Organic Plan Templates discusses the general requirements and includes copies of the plan templates for your use.
After speaking with a number of certifiers, it is my understanding that otherwise-prohibited treated lumber installations that already exist on an accredited farm will be allowed to remain, or be “grandfathered in,” by the renewing USDA/NOP accredited certifying agents. However, it is important to remember that any replacement posts or any facilities built after an application for certification is made must not use prohibited construction materials. The Final Rule of the NOP is very specific when it states:
Despite the fact that existing uses of treated lumber may be “grandfathered in,” if the certifying agents observe a situation in which treated lumber in an existing facility presents a significant contamination hazard, the certifying agents may require the producer to take some action before they grant certification. For this reason, it is important to communicate with the certifying agents and determine how they view your current situation. It is also wise to clearly state your intention to use only certifier-approved materials for replacement and new construction when you submit your Organic System Plan to your certifying organization. Options for Treated Lumber, Plywood, Wood Preservatives, and Fence PostsConsidering the many situations in organic operations where wood is in contact with soil, seed, feed, or livestock, organic producers and handlers will need acceptable materials. A number of alternatives are available, such as untreated wood, alternatively treated wood, stone, brick, steel, materials made from recycled plastics, cement board panels, concrete blocks, and concrete.
Before selecting which alternative products to use, the producer needs to evaluate each situation for:
The problem with untreated lumber is decay or rot, especially when the wood is placed in contact with the soil. Redwood, Eastern red cedar (juniper), Western red cedar, black locust, and bald cypress are domestic wood species that are naturally more decay-resistant than others. However, not only can durability vary among different wood species, it can even vary between trees of the same species or within one tree itself; this can cause a wide range of life expectancy for even highly durable wood. (Hoffman et al., 1995) One anecdotal source suggests that black locusts grown on poor soil are much more rot-resistant than those grown faster—in plantations—on good soil. Approved alternative wood preservatives can help extend the life expectancy for most wood (see Alternative Wood Treatments below). High demand for naturally decay-resistant wood has caused some species to be harvested at a pace much faster than the forest’s replacement rate. Young or second-growth trees are often less decay-resistant than mature trees. In some applications it may be desirable to avoid the expense and environmental impact of a decay-resistant wood species, choose an abundant, inexpensive, locally produced wood, and simply anticipate that the wood will need replacement after a period of time. The following sections cover alternative products and treatments for organic producers to evaluate with their certifying agents:
Other materials, such as stone, brick, steel, concrete, and concrete blocks are familiar and their usefulness and practicality are generally understood. Preservatives Applied Before PurchaseA limited number of alternative lumber treatments are available. These alternatives to CCA-treated lumber are free of arsenic, chromium, and other EPA-classified hazardous preservatives. However, they may contain ingredients that are synthetic or that are not yet evaluated by the National Organic Standards Board (NOSB) or approved by the NOP. The use of any of these alternative lumber products needs to be discussed in your Organic System Plan and with your certifying agents before any application or use. Borates
Borate wood treatments will penetrate to the center of the wood when the wood is dipped, especially when the wood is freshly cut or when seasoned wood is rewetted. However, because borates are water soluble, they will leach from the wood when in contact with water in the soil, leaving the wood unprotected. This is the reason that borate-treated lumber should be used only in locations that are at least 6 inches above the ground and protected from excessive rain. Borate-treated wood is not considered suitable for unprotected outdoor use, such as for fence posts or poles, but is suitable for most building construction purposes. Additional information on borate products and sources is available at the Green Builder Program’s Sustainable Building Sourcebook for “Wood Treatments” at www.greenbuilder.com/sourcebook/WoodTreatment.html. Ammoniacal Copper Citrate (CC) Thunderbolt, Inc. in Riverbank, California (see Further Resources) has CC pressure-treated wood available, and states that it is ideal for use as grape stakes and fence posts. Thunderbolt, Inc. explains that CC-treated wood products are safe for use around humans, animals, and plants. Remember that these products have not yet been evaluated by NOSB or approved by NOP, and their use needs to be discussed with your certifying agents and written into your Organic System Plan. Copper Azole (CBA) Copper azole is the formulation used in Wolman® E preservative for Natural Select™ wood. For information and a list of distributors visit Arch Wood Protection, Inc. (see Further Resources) or call 866-789-4567 (toll-free). Alkaline Copper Quaternary (ACQ) Preserve® and Preserve® Plus wood products are treated with Alkaline Copper Quaternary Ammonium (ACQ®). For additional information on these wood treatments and for an online searchable Distributors Locator, visit Chemical Specialties, Inc. Northern Crossarm Co., Inc.and Sunbelt Forest Products Corp. are two of the seventeen current producers of Preserve-treated wood in the U.S. (Chemical Specialties, Inc. 2002) Remember that these products have not yet been evaluated by the NOSB or approved by NOP, and their use needs to be discussed with your certifying agents and written into your Organic System Plan. Recycled Plastic Lumber and Plastic/Wood Composite Lumber“Lumber” made of recycled plastic or plastic/wood composite can provide durable, weather-resistant alternatives to wood for some applications. Formed plastic is approved only for use in non-structural applications, since it doesn’t have strength comparable to wood. However, plastic lumber can easily substitute for treated wood in non-structural applications, such as fences, sill plates, and raised beds. The plastics are rot- and corrosion-proof, and don’t crack, splinter, or chip. Even in exposed and sub-grade conditions, plastic lumber has a long life expectancy. It will not leach chemicals into ground or surface water or soil, as treated wood can. A challenging aspect of working with plastic lumber is its high expansion coefficient (varies for each product and manufacturer), which has to be considered when installing. The number of plastic lumber manufacturers and their variety of products have notably increased recently. Some companies use only High Density Polyethylene (HDPE) plastic, while others use commingled plastic wastes. A few manufacturers even mix plastic with recycled tire rubber. Some plastic lumber will contain wood fiber, which helps strengthen the plastic and reduces expansion. Plastic lumber is available in many configurations and sizes, including solid- and hollow-core dimensional products, and tongue-and-groove designs. The quality and product performance will vary by manufacturer; many manufacturers have independent testing results available. (NCAT Center for Resourceful Building Technology, 2002) The enclosed listing of recycled material suppliers, from King County, Washington, is an excellent source of contact information, available online at www.metrokc.gov/procure/green/vendors.htm. Alternatives to Treated Exterior PlywoodThere are a limited number of alternatives to treated exterior plywood, such as plastic panels, cement-board panels, and fiber-cement panels. For information on alternative products available in your area or regionally, check your local lumberyards or building centers, or visit the Web sites listed under Sources of Further Information below. Plastic Panels Polyboard sheets come in 4' x 8' sheets of various thicknesses from ¼” to 1". They are manufactured by Renew Resources, Ltd. in Toronto, Ontario, and are widely available. Contact Renew Resources at 800-439–5028 or 416-335–4040 for the nearest distributor. Another product is a recycled 4' x 8' sheet plastic made from 100% polyethylene plastic. It comes in a variety of sizes and thicknesses. For more information, contact Center Industries, Ltd. in Sioux Center, Iowa at 800-281–4049. Cement-board Panels and Fiber-cement Panels Plycem® is a noncombustible, structural, fiber-reinforced cement board. For additional information and location of the nearest distributor of Plycem®, contact U.S. Architectural Products, Inc. in Lincoln, Rhode Island at 800-243–6677 or 401-725–8550. Fiber-cement panel manufacturing companies are: Eternit, MaxiTile Inc., James Hardie Building Products, Georgia-Pacific, GAF Materials Corporation, American Fiber Cement Corporation, and CertainTeed. Information on many of these companies and their fiber-cement panels is available from NCAT’s Center for Resourceful Building Technology (CRBT) by searching the online Guide to Resource Efficient Building Elements under the heading of “Siding and Trim” at www.crbt.ncat.org. Preservatives Applied After PurchaseWood preservatives are treatments designed to sustain the structural and surface integrity of wood. They protect untreated exterior wood from rot, decay, and water damage. Alternative wood treatments can be applied on-site by brush, roller, dipping, or spraying. The following wood treatments are not on the National List of Allowed and Prohibited Substances and would need to be petitioned and evaluated by the NOSB for inclusion on the National List. (USDA, 2003) The use of any of these products needs to be discussed with your certifying agents before any application or use, and written into your Organic System Plan. One commercial exterior wood preservative is Wood Impregnation #99 manufactured by Bioshield Paint Company of Santa Fe, New Mexico. It can be used on garden fences, cold frames, and many other outdoor applications. Bioshield also manufactures paints, stains, thinners, and waxes that are made from such naturally-derived materials as citrus peel oils and solvents, essential oils, seed oils, tree resins, inert mineral fillers, tree and bee waxes, lead-free dryers, and earth pigments. For additional information on these products (including lists of ingredients) and for ordering information, visit the Bioshield Web site or call 800-621–2591 or 505-438–3448. Another commercial exterior wood preservative is AURO No. 121 Natural Resin Oil Primer distributed by Sinan Company of Davis, California. This product penetrates the wood deeply to protect from within, and allows moisture exchange. Sinan recommends that it be applied in one thin coat and followed up in most cases with a glaze, stain, wax, or varnish. Sinan distributes other AURO Natural Paint products that are also manufactured from natural raw materials, including a linseed oil that is organically grown and not diluted with any kind of petroleum solvents. For additional information on these products and for ordering information, contact Sinan or call 530-753–3104. Lifetime Wood Treatment is a wood preservative manufactured by Valhalla Wood Preservatives, Ltd. in Calgary, Alberta, Canada. During our phone conversation, the Lifetime representative stated that the product contains no toxic ingredients or poisons and is made up of naturally occurring plant and mineral substances, combined in a special wood-treatment recipe that has been handed down through generations of a family of wood craftsmen. Valhalla states that its product can be used in direct contact with garden soil without any toxic effect. It is a one-time application that is not supposed to wear off. Wood used in direct contact with the soil, such as posts or stakes, should be soaked in it for at least two days before setting in the soil. For additional information or ordering, call 403-228–5193 or visit www.valhalco.com. Lifetime Wood Treatment is not on the National List of Allowed Substances and would need to be petitioned and evaluated by the NOSB and approved by the NOP for inclusion on the National List. (USDA, 2003) Lifetime Wood Treatment use would need to be discussed with your certifying agents before any application and use, and written into your Organic System Plan. USDA-developed Wood Preservative
The original recipe calls for using paraffin wax, a petroleum derivative that is prohibited under the NOP section 205.105 (c), but a substitute like carnauba or wood rosin wax may work as well. Remember that before using this or any recipe, it is necessary to make sure that all the ingredients are listed on the National List of Allowed and Prohibited Substances as NOSB approved, or are approved by your organic certifiers. Ingredients:
Directions: Cautions and Suggestions: *Note: Copper-8-quinolinolate (oxine copper) is an organometalic compound and the formulation consists of at least 10% copper-8-quinolinolate, 10% nickel-2-ethylhexanoate, and 80% inert ingredients. Copper-8-quinolinolate is the only EPA-registered wood preservative permitted by the U.S. Food and Drug Administration for treatment of wood used in direct contact with food. It has a low toxicity to humans and animals, but is toxic to both wood decay fungi and insects. (Ibach, 1999) Alternative Fence PostsThe kinds of permanent or movable fences commonly used on farms include wood plank or rail, welded wire panel, barbed wire, woven wire, cable, plastic net, high-tensile, electric, or a combination of any of these. The various fencing materials and styles can all be used with alternative fence posts. The type of fence to use depends on the size and number of livestock, the purpose of the fence and the durability required, the soil type and terrain, and the types of crops and other vegetation that border the fence. Livestock will strongly test any fence when there is a lush green crop on the other side of it. Fences for handling facilities and confinement situations need to be stronger and taller than pasture, boundary, or temporary fences. An excellent online source of general fencing information is the Maryland Small Ruminant Page. It has links to many publications on different types of fencing materials and construction techniques, as well as a list of many of the fencing vendors and manufacturers. Another excellent source of information on fencing and grazing is the ATTRA publication Paddock Design, Fencing, and Water Systems for Controlled Grazing. One alternative to treated fence posts is untreated wood posts, but many species of wood used in fence posts rot rapidly when in contact with the ground. The enclosed publication from Cooperative Extension of the University of Nebraska-Lincoln, Native Wood Fence Posts (Schmidt and Kuhns, 1990), lists the expected lifespan of many untreated wood species used for fence posts, along with information on some of the advantages of seasoning posts before use. Three wood species are rated as having an expected lifespan of more than 20 years, even untreated. They are hedge (Osage orange), black locust, and Eastern red cedar (juniper). Depending on your location, these species may be available locally at sawmills or at lumberyards. Hedge posts and poles are available from Smith Postyard (see Further Resources). According to Native Wood Fence Posts, most of the other wood species have shorter expected lifespans and require some method of protection from moisture. One method of protecting untreated fence posts is to wrap the part in the ground with plastic. (Quarles, 2002) Another method of protection is to use an alternative exterior wood treatment to improve the post’s life span (see Preservatives Applied After Purchase section above). However, these alternative treatments are not yet evaluated or approved by the NOSB, and their use needs to be documented in your Organic Farm Plan and discussed with your certifying inspection agents before any application or use. Besides untreated or alternatively treated wood fence posts, other options include plastic, steel T–posts, steel pipe, concrete, fiberglass, or even concrete–filled PVC pipe. These fence posts will vary in cost, availability, and practicality for each specific fencing need. Many of the plastic fence posts are made from recycled plastic containers. They come in various lengths, dimensions, and colors; can be stapled, drilled, or cut like wood; and are self-insulating for electric fencing. Different fencing companies have various types of plastic posts available. Many of these companies can be located at the Maryland Small Ruminant Page. Sources of Further InformationGeneral information on environmentally responsible building materials and practices in construction is available from NCAT’s Center for Resourceful Building Technology (CRBT) (see Further Resources). CRBT identifies and promotes building products and methods that reuse salvaged, currently underutilized, or waste materials, and produce less pollution and waste than conventional materials and technologies. The CRBT also provides an excellent, searchable Guide to Resource Efficient Building Elements. The Green Building Program’s Sustainable Building Sourcebook also provides excellent information and sources of environmentally responsible building materials, such as wood treatments, dimensional lumber, engineered sheet materials, and others. The Sourcebook provides Web access to detailed guidelines and resources on many different environmentally friendly building materials that would otherwise be difficult to find. The Sourcebook is available at www.greenbuilder.com/sourcebook/. ReferencesAnon. 2001/2002. Arsenic seeps into the spotlight. Mother Earth News. December–January. p. 18. Chemical Specialties Inc. 2001. Preserve Fact Sheet. www.treatedwood.com/products/preserve/faq.html Chemical Specialties Inc. 2002. Chemical Specialties, Inc. (CSI), based in Charlotte, N.C., offers arsenic-free ACQ Preserve wood preservative technology. Daar, Sheila and William Olkowski. 2002. Moisture management to prevent wood decay. Common Sense Pest Control. Winter. p. 3–12. EPA. 2002. Whitman announces transition from consumer use to treated wood containing arsenic. EPA Headquarters Press Release. February 12. 3 p. Hoffman, Thomas R., Lewis T. Hendricks, and Kevin Powell. 1995. Selecting Preservative Treated Wood. University of Minnesota Extension. 17 p. www.extension.umn.edu/distribution/housingandclothing/DK0897.html Ibach, Rebecca E. 1999. Wood Preservatives. In: Wood Handbook: Wood as a Engineering Material. Forest Products Laboratory, USDA Forest Service. March. 28 p. www.fpl.fs.fed.us/documnts/fplgtr/fplgtr113/fplgtr113.htm Lebow, Stan. 2000. What’s in that pressure-treated wood? Techline. USDA Forest Service, Forest Products Laboratory. July. 3 p. www.fpl.fs.fed.us/documnts/techline/whats-in-that-pressure-treated-wood.pdf (PDF / 269 K) Lebow, Stan and Michael Tipple. 2001. Guide for minimizing the effect of preservative-treated wood on sensitive environments. USDA Forest Service, Forest Products Laboratory. General Technical Report 122. February. 18 p. www.wwpinstitute.org/pdffiles/fplgtr122.pdf MacMillen, Andrew. 1995. Treated wood: Is it safe? 2 p. www.efn.org/~andrewm/hhd/wood.html (Link no longer active). Moore, Steven. 1993. Pressure-treated wood: Is it the right kind of green? Cognition. Fall. p. 31– 32. NCAT Center for Resourceful Building Technology. 2002. Landscaping: Recycled plastic lumber. 2 p. http://crbt.ncat.org/landscape.html Public Health Seattle & King County. 2000. Treated woods for garden use: What is safe? 3 p. www.metrokc.gov/health/hazard/treatedwood.htm Quarles, William. 1998. Borates for wood protection. The IPM Practitioner. Vol. 20, No. 3. March. p. 1–12. Quarles, William. 2002. Alternatives to arsenic-treated wood. Common Sense Pest Control. Winter. p. 13–22. Rodale, Inc. 2000. Treated wood: Dangerous and Still Unregulated. 2 p. www.organicgardening.com/watchdog/treatedwood.html (Link no longer active). Rodale, Inc. 2001. A safe way to preserve wood. 1 p. www.organicgardening.com/watchdog/treatedwoodself.html (Link no longer active). Schmidt, Thomas L. and Michael R. Kuhns. 1990. Native Wood Fence Posts. Cooperative Extension, University of Nebraska-Lincoln. G76-314. 5 p. http://ianrsearch3.unl.edu/pubsarchive/forestry/g314.htm Stehouwer, Richard. 2001. Garden use of treated lumber. Environmental Soil Issues. PennState Agricultural Research and Cooperative Enxtension. 4 p. http://pubs.cas.psu.edu/freepubs/pdfs/uc173.pdf (PDF / 66 K) USDA. 2000. National Organic Program Final Rule. Federal Registry. Vol. 65, No. 246. Thurs., December 21. p. 41-42, 72, 496. http://www.ams.usda.gov/nop/NOP/standards/FullText.pdf (PDF / 1.2 M) USDA. 2003. The National List of Allowed and Prohibited Substances. 11 p. www.ams.usda.gov/nop/NOP/standards/ListReg.html Williams, Greg and Pat. 2002. An alternative to CCA-treated wood. HortIdeas. January. p.7. EnclosuresKing County Environmental Purchasing Program. 2001. Recycled material suppliers. 3 p. www.metrokc.gov/procure/green/vendors.htm Schmidt, Thomas L. and Michael R. Kuhns. 1990. Native Wood Fence Posts. Cooperative Extension, University of Nebraska-Lincoln. G76-314. 5 p. http://ianrsearch3.unl.edu/pubsarchive/forestry/g314.htm Further Resources Bio-Integral Resource Center (BIRC)
NCAT Center for Resourceful Building Technology (CRBT)
USDA Forest Service
Smith Postyard
Chemical Specialties Inc. (CSI)
Arch Wood Protection, Inc.
Thunderbolt, Inc.
EZHutch®
NRP Plastics Inc.
JSI™ Innovations
Acknowledgements Organic Alternatives to Treated Lumber
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