---------- Forwarded message ---------- Date: Sun, 6 Jul 1997 14:20:23 -0400 From: Huck_DeVenzio@HicksonCorp.COM To: london@sunsite.unc.edu Subject: Info on pressure-treated wood Mr. London: I saw your posting on the Green building list and visited the site you referred to (http://sunsite.unc.edu/InterGarden/pested/faqs/pressure-treated-lumber). Many of the comments, as you noted, are opinions, and there are a number of inaccuracate and misleading statements; nothing is newer than 1994. Is there some way that other sources could be added? I am in the treated wood industry, so I have a pro-treatment bias, but there have been recent noteworthy discussions on CCA-treated wood on the Greenbuilding list (not all favorable) and the Gardens list (gardens@lsv.uky.edu). I think the most reliable information is available from our industry by visiting www.awpi.org or the Hickson site at www.hickson.com. If people are looking for factual information on this issue, these web sites would be useful. Thanks. Newsgroups: rec.gardens Subject: Is CCA PT lumber OK for a [Pressure Treated Lumber faq1 - gen. info] From: jim.mcnelly@gcbb.granite.mn.org (Jim Mcnelly) Date: Sat, 9 Apr 94 13:06:00 +0600 Organization: Granite Information Svs. 612-654-8372 hst 656-0678 v.32bis Doug Caprette asks: D>Hmm, I get the impression that I may have just missed a discussion on this >topic. D>Anyway, can anyone provide some informed opinion as to whether there would be >any problems anticipated with the use of Chromated copper arsenate treated >lumber for a grape arbor? Here is my FAQ on Arsenic Lumber, and in another post, the product safety sheet that is *supposed* to be handed out to every purchaser of the product which was a part of the EPA agreement to allow the product to be sold. Additional information on CCA, Chromated Copper Arsenate. The wood has been tested by the Minnesota Pollution Control Agency, Hazardous Waste section to be over 3000 parts per million arsenic. The EPA limit on arsenic in sewage sludge for unrestricted use is 11 PPM. There is at least one case of 24 cows dying from eating ash from CCA wood ash in MN and several cases in other states. There is another case of arsenic poisoning in a Wisconsin family from a backdraft in their fireplace while burning treated wood. Arsenic is associated with hair loss, diarrhea, asthma, skin cancer and other skin disorders. Particular caution should be exercised if the wood has a white, gritty residue on the surface, as these may be arsenic crystals. Penetrating oil stain may slow down weathering of fibers and reduce arsenic surface residues. The exposed ends of boards are more likely to leach arsenic than the rest of the board. The wood should be resealed every two years. Of particular concern is sawdust left at construction sites that can he ingested by children, pets, or become exposed to the skin. Runoff of sawdust into ponds, pools, wells and gardens is another concern. Arsenic is rated by the EPA as a class A carcinogen, the top level of risk. Children "mouthing" the wood are also at risk, especially the board ends that release twelve times the arsenic of the rest of the wood. This is especially a concern as arsenic treated wood is a common component in playground equipment. Tests for arsenic beneath children's play equipment have run as high as hundreds of times above background levels. Treated wood is also a problem in disposal. While such a broad range biocide such as CCA retards decay, it does not stop it. Estimates of rot resistance of 20 to 50 years are common. The wood will *eventually* decay, and with the sawdust and ends from construction, will have to go somewhere. The treated wood industries have lobbied to have CCA treated wood exempted from hazardous waste designation through a de-listing procedure that is still unclear. The product is currently allowed to be sent to conventional and demolition landfills. It is often burned with other wood wastes and is commonly chipped into landscape mulch or compressed into toxic fuel pellets. It releases toxic fumes and ash in house fires, putting neighbors and firefighters at extra risk. The ash from a burned CCA patio deck is not managed as the hazardous material it is. The argument from the treated wood industry has been that the arsenic does not leach from the wood fiber under normal soil conditions. While this is somewhat true, it is misleading. The wood will _eventually_ decay and leach its metals and there is currently no safe disposal. The practice of burning wood scraps and the mismanagement of the wood both residentially and commercially has resulted in airborne arsenic levels increasing nationwide, especially in the major cities where scavengers burn scrap wood for heat. Most uses of the wood such as decks, fences, and stakes are not necessary for such extreme wood treatment. Only in the Southeast is the potential of climate high in promoting decay. There is no need for treated wood at all in the west, except on the northwest coast. Because of these concerns, but primarily due to the threats of the wood to commercial organic wood recycling, I am recommending that the product only be sold or used by licensed and trained professionals, similar to other hazardous pesticides, and that it be banned from non-hazardous land disposal sites. Mr Compost~~~ Jim~ McNelly ReSourceNet and GardenNet 612-654-8372, 656-0678 v.32bis jim.mcnelly@granite.mn.org Newsgroups: rec.gardens Subject: Is CCA PT lumber OK for [PT Lumber faq2-Consumer Information Sheet] From: jim.mcnelly@gcbb.granite.mn.org (Jim Mcnelly) Date: Sat, 9 Apr 94 13:06:00 +0600 Organization: Granite Information Svs. 612-654-8372 hst 656-0678 v.32bis Doug Caprette asks: D>Hmm, I get the impression that I may have just missed a discussion on this >topic. D>Anyway, can anyone provide some informed opinion as to whether there would be >any problems anticipated with the use of Chromated copper arsenate treated >lumber for a grape arbor? Here is the Consumer Information Sheet about pressure treated wood that I received from the American Wood Preserver's Association, PO Box 5283, Springfield, VA 22150 that is SUPPOSED to be provided to every purchaser of CCA, ACA, and ACZA treated wood. This is exactly as it appears without editing. "This wood has been preserved by pressure treatment with an EPA registered pesticide containing inorganic arsenic to protect it from insect attack and decay. Wood treated with inorganic arsenic should be used only where such protection is important. Inorganic arsenic penetrates deeply and remains in the pressure treated wood for a long time. Exposure to inorganic arsenic may present certain hazards. Therefore, the following precautions should be taken when handling the treated wood and in determining where to use or dispose of the treated wood. USE SITE PRECAUTIONS Wood pressure treated with waterborne arsenical preservatives may be used inside residences as long as all sawdust and construction debris are cleaned up and disposed after construction. Do not use treated wood under circumstances where the preservative may become a component of food or animal feed. Examples for such sites would be structures or containers for storing silage or food. Do not use treated wood for cutting boards or counter tops. Only treated wood that is visibly clean and free of surface residue should be used for patios, decks, and walkways. Do not use treated wood for construction of beehives that may come in contact with honey. Treated wood should not be used where it may come into direct or indirect contact with public drinking water, except for uses involving incidental contact such as docks and bridges. HANDLING PRECAUTIONS Dispose of treated wood by ordinary trash collection or burial. Treated wood should not be burned in open fires or in stoves, fireplaces, or residential boilers because toxic chemicals may be produced as a part of the smoke and ashes. Treated wood from commercial or industrial use (e.g construction sites) may be burned only in commercial or industrial incinerators or boilers in accordance with state and federal regulations. Avoid frequent or prolonged inhalation of sawdust from treated wood. When sawing and machining treated wood, wear a dust mask. Whenever possible, these operations should be performed outdoors to avoid indoor accumulations of airborne sawdust from treated wood. When power sawing and machining, wear goggles to protect eyes from flying particles. After working with the wood, and before eating, drinking, and use of tobacco products, wash exposed areas thoroughly. Mr Compost~~~ Jim~ McNelly ReSourceNet and GardenNet 612-654-8372, 656-0678 v.32bis jim.mcnelly@granite.mn.org --- * April 9th - Galactic Wanderer Newsgroups: rec.gardens Subject: PT Lumber [PT Lumber faq3 - more general information] From: jim.mcnelly@gcbb.granite.mn.org (Jim Mcnelly) Date: Tue, 25 Jan 94 00:40:00 +0600 Organization: Granite City Info Center 612-654-8372 hst 656-0678 v.32bis >I don't need to be convinced not to put arsenic in my back yard, >but I was wondering if you could give me the references for those >facts and figures you gave about the hazards of PT sawdust and >the eventual disposal problems of PT wood. My source(s) include the Minnesota Pollution Control Agency Hazardous Waste Section, the tests of the Benton County Solid Waste District (Foley Minnesota), and independent laboratory analysis conducted under the supervision of the MNPCA. I have also provided several samples to independent laboratories on my own and have confirmed the arsenic and lead levels. The 21 dead cows were verified by the State Veterinarian, actually ordered to be destroyed by him due to the diagnosis of arsenic poisoning and arsenic in the milk. The cases of humans overcome by arsenic smoke I have from conducting an electronic search of various national newspapers for the word "arsenic". You can imagine sifting through the reports on the reported poisoning of President Zachary Taylor and reviews of various presentations of the play, "Arsenic and old Lace". The EPA standards on arsenic levels in compost and sludge are from the EPA 503 sludge rules (11 PPM vs 3000 PPM in PTwood) which are published in the Federal Register and available from your regional EPA office. The toxicity reactions of arsenic, symptoms, and treatment are from any good medical encyclopedia, my copy from toxicity reference documents used at the Mayo Clinic here in Minnesota. You can also find a copy of "Arsenic, Chromium, and Copper Poisoning form Burning Treated Wood" in "The New England Journal of Medicine" June 2, 1983 which reports the effects of arsenic poisoning in a family exposed to burning arsenic (treated) wood in the fireplace. According to the three doctors at the University of Wisconsin, the family had "symptoms of conjunctivitis, bronchitis, pneumonia, sensory hyperesthesia of the arms and legs, muscle cramps, dermatitis of over the arms and legs and soles of the feet, nosebleeds, ear infections, blackouts and seizures, gastrointestinal disturbances, and severe alopecia." "Investigation revealed the presence of high amounts of arsenic in the hair of the parents (12 to 87 PPM; normal less than .65) levels in the fingernails 100 to 5,000 ppm; normal .9) Samples of dust in the home revealed levels of arsenic up to 2,000 ppm." You can look at an article called "The Phone Poles that Will Not Die" from "MSW Management" Nov/Dec 1992. Check also "Env Pollution" 14.213 26 by C. Grant and A.J. Dobbs "The growth and metal content of plants grown in soil contaminated by a copper chromium arsenic wood preservative". I also have references (Woodson 1971, Chisolm 1972, Hess and Blanchar 1977) that arsenic at 2500 PPM is a complete soil sterilant and that sensitive plants show phytotoxicity from 1 PPM to 50 PPM if the arsenic is in an extractable form. Arsenic reacts with plants being substituted for phosphorous (Asher and Reay 1979) and its effects can be limited by supplemental applications of phosphate. I would like to try to >convince someone not to use any more of the stuff for picnic >tables and the like and I need cold hard facts! I believe that it is nearly impossible to convince people of the biohazard of treated lumber, which is the major reason why I am calling for its removal from public use. They seem to refuse to believe that the words "treated" or "pressure" means arsenic, or believe that arsenic is indeed a poison. People simply want to believe that since the product is at the lumber yard, it is the same as regular lumber. One neighbor I tried to keep from burning scraps insisted that the wood was "salted" and that salt was "OK". KAW>I had always been concerned about the problem of leaching because >of the O.G. articles, but now I am more concerned about the vast >quantities of this stuff being used for non-gardening structures >- >(kids jungle-gyms, decks, etc.) .... I need to convince my >neighbor not to put the scraps in the "burn pile" - There is an architect named Cameron Duncan who has led a "one man" fight against treated lumber in school play equipment. He has been intimidated, threatened, slandered, and has had lost business as a result of his efforts. There has been virtually no support for his efforts aside from the National Coalition against the Misuse of Pesticides, which will provide information at a fee. Their number is 202-543-5450. Mr Compost~~~ Jim McNelly~~~ Granite Information Service 612-654-8372-HST 656-0678 v.32bis jim.mcnelly@granite.mn.org Newsgroups: rec.gardens Subject: arsenic soil contaminatio From: jim.mcnelly@gcbb.granite.mn.org (Jim Mcnelly) Date: Tue, 25 Jan 94 00:40:00 +0600 Organization: Granite City Info Center 612-654-8372 hst 656-0678 v.32bis CA>am curious about HOW TO TEST some LUMBER used for a retaining wall in the >backyard. My concern is that this wood is also a defining edge of my >vegetable >garden. Is there somewhere I could send a chunk of this wood to have it >analyzed? I have no idea if it was treated lumber or not; I suspect it was. Try the local Agricultural extension office, the university, an agricultural testing laboratory, or a private laboratory. Have them test for soil mineral content, making sure that there is a test for copper in the bunch. Arsenic testing is expensive. Mr Compost~~~ Jim McNelly~~~ Granite Information Service 612-654-8372-HST 656-0678 v.32bis jim.mcnelly@granite.mn.org Newsgroups: rec.gardens Subject: Re: Pressure Treated Lumb From: jim.mcnelly@gcbb.granite.mn.org (Jim Mcnelly) Date: Wed, 19 Jan 94 16:27:00 +0600 Organization: Granite City Info Center 612-654-8372 hst 656-0678 v.32bis Subject: Re: Pressure Treated Lumb Ray Foster to All - Wednesday, January 19th: Discussing: Re: Pressure Treated Lumber RF>OK, a question from someone to whom this is all new: how can you tell if lum >has been treated with CCA? RF>We bought a house this past summer. The previous owner had built some raised >gardens beds using wood. How can I tell whether this is pressure treated woo Ray, you bring up the chief reason why I believe that arsenic amended wood should be installed only by licensed pesticide professionals and that its installation should be clearly identified in the deed of the property, with full chain of custody like hazardous materials in the commercial arena. Aside from the distinctive green or brown tint, there really is no way to tell. You may try notching or scratching the wood and see if it is still stained, since the arsenic, lead, copper, and chromium penetrate to the core of the wood. This is just one more piece of evidence why I believe the product should be banned. At least the wood could be imprinted with the words "danger - arsenic" burned into every surface. Testing for copper is much cheaper than arsenic, if you care to have the wood analyzed. Jim McNelly~~~ Granite Cities BBS 612-654-8372-HST 656-0678 v.32bis jim.mcnelly@granite.mn.org From: mcgrew@ichthous.Eng.Sun.COM (Darin McGrew) Newsgroups: rec.gardens Subject: Re: Pressure Treated Lumb Date: 21 Jan 1994 18:10:02 GMT jim.mcnelly@gcbb.granite.mn.org (Jim Mcnelly) writes: >This is just one more piece of evidence why I believe the product should >be banned. At least the wood could be imprinted with the words >"danger - arsenic" burned into every surface. I think you'll have better luck getting its presence recorded on the deed. DIY handymen (and probably some professionals) would try to remove the warning from visible surfaces with a plane, and then you have toxic wood shavings in addition to the toxic sawdust and wood scraps. BTW, thanks for pointing out that the big problem isn't whether or not the toxins leach into the garden soil, but what becomes of the treated wood after its useful life. Newsgroups: rec.gardens From: nathan@seldon.foundation.tricon.com (Number 6) Subject: Re: Pressure Treated Lumb Date: Wed, 19 Jan 1994 00:32:10 GMT I think the *best* way to get people to realize the dangers of pressure treated lumber is the one suggested by "Mr. Compost" (sorry, I'm in my "primitive" news reader now...so I can't get the real name). Here in California and probably just about everywhere else, you have to sign your life away on lead paint. It is a requirement for most types of loans (mostly Federal Gov't backed ones). We had to sign so many disclosures to buy this house it was incredible but I was glad that they TOLD us what we were getting into (possibly). [We don't have lead paint, btw]. So, a first step is getting the state or the federal government to look at the research and then draft up a disclosure statement that must be signed by all homeowners when applying for the loan. This does NOT mean that people will actually read it, unfortunately. But, if they sign it, and then try to sue somebody, it'll fly back into their face for not reading it. Also, I think all landfills that are unlined should just stop taking the stuff. We get all our water from the ground and I shudder to think what the local toxic waste dump cleanup that's in progress is finding out! (Not to mention what Unocal Oil is dumping into our water). btw does anyone know how to tell pressure treated lumber? I may have some of that in my garden hope not. I don't think it is because it's falling apart and rotting and is not all that old. ("Railroad" ties as an edging material). Newsgroups: rec.gardens Subject: Re: Pressure Treated Lumb From: jim.mcnelly@gcbb.granite.mn.org (Jim Mcnelly) Date: Wed, 19 Jan 94 22:50:00 +0600 Organization: Granite City Info Center 612-654-8372 hst 656-0678 v.32bis Subject: Re: Pressure Treated Lumb Pauls@Pender.Ee.Upenn.Edu to All - Wednesday, January 19th: Discussing: Re: Pressure Treated Lumber >jim.mcnelly@gcbb.granite.mn.org (Jim McNelly) writes: >>I say it is time to blow the whistle on arsenic in the back yard and put >>a stop to it once and for all, and dedicate our environmental efforts to >>ensure safe ultimate disposal. P>I still have not seen any conclusive evidence that treated wood is >harmful. There is evidence that arsenic leaches out into the soil. >So what? I have seen no evidence that it is in harmful quantities. >Can you site any conclusive experiments to support you position on CCA >lumber? Paul, I believe your question is valid. Due to the lack of evidence that I believe is substantive, I have not made the claim that arsenic leaching from treated wood to the soil is a biohazard. Organic Gardening and other sources may make that claim, but I have not. As to whether or not arsenic is harmful, you *must* be kidding. My problem with treated wood is its uncontrolled use, its misuse, and its ultimate disposal. The uncontrolled use problem is the situation where it is used for building decks and other outdoor applications not in contact with the soil. Conventional treating of pine with water sealants is adequate without adding an arsenic load to the biosphere. Treated wood is designed for direct soil contact where the soil is moist. Other applications are not advised, but people use arsenic wood because they are too lazy to seal pine. Arsenic wood should be sealed anyway, but too few do it. One misuse is in its manufacture, of which the 400 manufacturing sites in the US are largely unregulated. Many are Superfund sites waiting to happen. Another misuse is the spreading of sawdust and shavings into the soil. These *do* leach arsenic, especially as sawdust floats in stormwater runoff. Arsenic is being found in ponds and surface water. Sawdust run off has been linked to deaths of exotic fish in back yard ponds. Sudden kills of Koi after installing a deck or other arsenic landscape project are being increasingly reported. The worst misuse is from burning arsenic treated wood scraps and arsenic in ash from house fires. This form of arsenic is no longer bound in the wood fiber and is highly volatile at 3000 parts per million. Arsenic ash is a class 1 carcinogen as rated by the EPA. By law, arsenic ash must be sent to a hazardous waste disposal site. Currently it is not. I call that misuse. I have documentation from the Minnesota Hazardous Waste Management Department of 24 dairy cows killed from eating arsenic ash from uncontrolled burning of treated lumber. I have news reports of three other cattle poisonings, and several cases of deer-kills from eating arsenic ash. There are three documented cases of families being overcome or exposed to arsenic requiring medical attention from arsenic fumes from burning treated wood in fireplaces and outdoor fires. I have copies of medical textbooks outlining the effects of arsenic poisoning and treatment, of which diarrhea and neural damage come from ingestion. The most significant danger to humans is arsenic on the skin, which even in small quantities can cause skin cancer. The doubling of the rate of skin cancer (albeit coincidentally) parallels the time period when arsenic wood was introduced to the environment. The pathways of exposure can come from working with the wood without gloves or protective clothing or getting the dust on the body. It can also come from walking on treated wood with bare feet or mouthing the wood, especially cut ends and nicks. Ash contact with the skin, even from a fire miles away can cause skin cancer. Children playing in the dirt where arsenic sawdust was left years previously can be a means of arsenic exposure. The arsenic levels under treated wood play equipment have been tested at 200 times background levels. The documentation on the use of treated wood tell users to wear protective clothing, shower after working, vacuum the sawdust, refrain from smoking and eating, and to send the scraps to the landfill. How often are buyers give the instructions for safe use? How many follow the recommended practices? Hardly any, which is why I call it a product out of control. P>Garden built with x square feet of CCA treated wood in various stages >of decomposition: new, old, severly decayed, chips/sawdust. Then test >soil at various levels and distances from the wood and test the >vegetables. The data I have seen has shown me that the arsenic is not leaching into the soil, and the pathway of ingestion is difficult to substantiate. If anyone has evidence to the contrary, I have yet to see it. Until I see firm documentation, I will not claim that arsenic leaching from properly treated wood is the problem. The treated wood industry has repeatedly engaged me on other Bulletin Boards in arguing the issue of leachability, of which I concede their points. Frankly I am surprised they are not here on rec.gardens with their party line of "no leach in soul equals safe" argument. My argument is not leachability and uptake by plants, it is the issue of the widespread abuse of the product that I am concerned about. P>This combined with a clear explaination of what levels are considered >harmful to humans in food would be conclusive. The harmful levels in food are not the issue as I mentioned previously. The harm is in uncontrolled sawdust, waste, and ash. The rate of decomposition of treated wood is understood, but the wood has only been on the market for about fifty years, with 90% of total sales within the past fifteen. The wood has yet to rot to the point of being a leaching problem...... yet. No one denies that it is a matter of time when it is a leaching problem. Then we will have arsenic on root vegetables, children eating arsenic contaminated soil, children playing in arsenic rotted wood, airborne arsenic dust, arsenic silt run off and so forth. It will be a major problem around the year 2025. A sad legacy because people won't take the effort to seal pine when building decks, in my opinion. P>Has such a test been conducted? If not, Why not? The tests have been conducted, and they show the arsenic not to be leaching. But the wood *will* eventually rot, and then the arsenic will start leaching. The treated lumber industry only gives the wood a 60 year life expectancy in the soil. Which means in 60 years, the next generation will be dealing with disposing of leaching, rotting, arsenic contaminated wood mould rather than stable boards. Again my point of last week is to identify the location of the wood and ensure that it is well marked and not accidentally removed and disposed of improperly. When it does age, let's use the figure of 40 years, it should be removed from the soil before it rots and taken to a hazardous waste disposal site. I say to stop its uncontrolled sale and reserve its use for applications that are demonstrated to require a biocide treated wood. Then to track its location and ultimate disposal, just like any other biohazard is managed in commercial use. The household exemption for hazardous waste can no longer be swept under the rug. What goes into the environment has to be accounted for. I do not consider myself to be an environmental extremist and work with scientific principles regarding metal accumulations in soil on a regular basis in my professional capacity as an organic matter management specialist. Arsenic levels have become a concern in wood scrap grinding operations as levels over 11 PPM are not allowed to go into the soil in compost, sludge, or fuel. I can document many cases of wood scrap recyclers having to send tens of thousands of tons of wood chips to landfills because of treated wood contamination Mr Compost~~~ Jim McNelly~~~ Granite Information Service 612-654-8372-HST 656-0678 v.32bis jim.mcnelly@granite.mn.org Newsgroups: rec.gardens From: os2user@brdiller.houston.ibm.com (Barry Diller) Subject: Re: Pressure Treated Lumb Date: Wed, 19 Jan 1994 23:39:18 GMT Lines: 95 >>I say it is time to blow the whistle on arsenic in the back yard and put >>a stop to it once and for all, and dedicate our environmental efforts to >>ensure safe ultimate disposal. >I am very concerned about arsenic poisoning, and I plan to remove the treated >wood from around my gardens this spring just to be safe. That is, just >IN CASE it actually is harmful. I can due without the wood, so why take >any chance is my position. I think that this pretty well summarized my opinion on this matter until I read Jim McNelly's post, which you've partially quoted above. >I still have not seen any conclusive evidence that treated wood is >harmful. There is evidence that arsenic leaches out into the soil. >So what? I have seen no evidence that it is in harmful quantities. I think you're missing what I considered to be Mr. McNelly's main point: "Properly processed treated wood does not leach arsenic under normal conditions. How we, the public and the environmental community, focused on this one narrow issue and missed the rest of the story, the story about the sawdust, the scraps, the ash, and the ultimate disposal is shameful." Now, we can all argue here about how much arsenic actually leaches into our garden soil from CCA lumber under different conditions, and we can talk about what PPM of arsenic in our garden soil might be an intolerable amount, and so forth - and those would probably be some very useful discussions - but the larger issue is what is to become of all our CCA lumber when we're finished with it. Is CCA lumber going to be the 'asbestos' of the 1990's or 2000's? >Can you site any conclusive experiments to support you position on CCA >lumber? The warning label that comes on the wood is not conclusive. >In reading this group, there seem to be more posts >saying the wood is ok than there are saying it is harmful. Without >conclusive evidence from multiple sources I do not believe we or any >other group will have a chance of removing this poison from common >houshold use in decks and gardens. I heard about the article in Organic >Gardening, but have not yet read it. I also heard that it was not >quantitative. I want more than just scare tactics from the environmentally >extreme. I want the facts. Is this wood dangerous or not? Until the >facts are revealed, I will not be using treated lumber just in case. >If there is so much concern about this stuff why arn't there more tests? >I want answers like this: > >Garden built with x square feet of CCA treated wood in various stages >of decomposition: new, old, severly decayed, chips/sawdust. Then test >soil at various levels and distances from the wood and test the vegetables. >Then publish results: >This combined with a clear explaination of what levels are considered >harmful to humans in food would be conclusive. And if the levels of leached arsenic proved acceptable to you, will you then go out and buy a couple of tons of CCA lumber and place it in your backyard? Are you prepared to handle the lumber properly during construction? What are you going to do with the sawdust and scraps - send them to your local landfill? Burn them? And what will you do in 20 years when the lumber has turned to mush, or in 5 years when you decide to remodel or re-landscape? Please re-read Jim McNelly's note. Arsenic 'leaching' is not CCA lumber's biggest liability. >Has such a test been conducted? If not, Why not? ------------------------------------------------------------------------------- Barry R. Diller IBM Federal Sector Sevices Company EMail address: brdiller@vnet.ibm.com Houston, Texas USA Newsgroups: rec.gardens Subject: Re: Pressure Treated Lumb From: jim.mcnelly@gcbb.granite.mn.org (Jim Mcnelly) Date: Fri, 21 Jan 94 00:02:00 +0600 Organization: Granite City Info Center 612-654-8372 hst 656-0678 v.32bis Subject: Re: Pressure Treated Lumb Pauls@Pender.Ee.Upenn.Edu to All - Wednesday, January 19th: Discussing: Re: Pressure Treated Lumber >jim.mcnelly@gcbb.granite.mn.org (Jim McNelly) writes: >>I say it is time to blow the whistle on arsenic in the back yard and put >>a stop to it once and for all, and dedicate our environmental efforts to >>ensure safe ultimate disposal. P>I still have not seen any conclusive evidence that treated wood is >harmful. There is evidence that arsenic leaches out into the soil. >So what? I have seen no evidence that it is in harmful quantities. >Can you site any conclusive experiments to support you position on CCA >lumber? Paul, I believe your question is valid. Due to the lack of evidence that I believe is substantive, I have not made the claim that arsenic leaching from treated wood to the soil is a biohazard. Organic Gardening and other sources may make that claim, but I have not. My problem with treated wood is is uncontrolled use, its misuse, and its ultimate disposal. The uncontrolled use problem is the situation where it is used for building decks and other outdoor applications not in contact with the soil. Conventional treating of pine with water sealants is adequate without adding an arsenic load to the biosphere. Treated wood is designed for direct soil contact where the soil is moist. Other applications are not advised. One misuse is in its manufacture, of which the 400 manufacturing sites in the US are largely unregulated. Many are Superfund sites waiting to happen. Another misuse is the spreading of sawdust and shavings into the soil. These *do* leach arsenic, especially as sawdust floats in stormwater runoff. Arsenic is being found in ponds and surface water. The worst misuse is from burning arsenic treated wood scraps and arsenic in ash from house fires. This form of arsenic is no longer bound in the wood fiber and is highly volatile at 3000 parts per million. Arsenic ash is a class 1 carcinogen as rated by the EPA. By law, arsenic ash must be sent to a hazardous waste disposal site. Currently it is not. I call that misuse. I have documentation from the Minnesota Hazardous Waste Management Department of 24 dairy cows killed from eating arsenic ash from uncontrolled burning of treated lumber. I have news reports of three other cattle poisonings, and several cases of deer-kills from eating arsenic ash. There are three documented cases of families being overcome from arsenic fumes from burning treated wood in fireplaces and outdoor fires. I have copies of medical textbooks outlining the effects of arsenic poisoning and treatment, of which diarrhea and neural damage come from ingestion. The most significant danger to humans is arsenic on the skin, even in small quantities which the main symptom is skin cancer. This is caused from working with the wood without gloves or protective clothing and getting the dust on the body. It can also come from walking on treated wood with bare feet. Ash contact with the skin, even from a fire miles away can cause skin cancer. P>Garden built with x square feet of CCA treated wood in various stages >of decomposition: new, old, severly decayed, chips/sawdust. Then test >soil at various levels and distances from the wood and test the >vegetables. The data I have seen has shown me that the arsenic is not leaching into the soil, and the pathway of ingestion is difficult to substantiate. If anyone has evidence to the contrary, I have yet to see it. Until I see firm documentation, I will not claim that arsenic leaching from properly treated wood is the problem. P>This combined with a clear explaination of what levels are considered >harmful to humans in food would be conclusive. The harmful levels in food are not the issue as I mentioned previously. The harm is in uncontrolled sawdust and ash. The rate of decomposition of treated wood is understood, but the wood has only been on the market for about fifty years, with 90% of total sales within the past fifteen. P>Has such a test been conducted? If not, Why not? The tests have been conducted, and they show the arsenic not to be leaching. But the wood *will* eventually rot, and then the arsenic will start leaching. The treated lumber industry only gives the wood a 60 year life expectancy in the soil. Which means in 60 years, the next generation will be dealing with disposing of leaching, rotting, arsenic contaminated wood mould rather than stable boards. Again my point of last week is to identify the location of the wood and ensure that it is well marked and not accidentally removed and disposed of improperly. When it does age, let's use the figure of 40 years, it should be removed from the soil before it rots and taken to a hazardous waste disposal site. I do not consider myself to be an environmental extremist and work with scientific principles regarding metal accumulations in soil on a regular basis in my professional capacity as an organic matter management specialist. Arsenic levels have become a concern in wood scrap grinding operations as levels over 11 PPM are not allowed to go into the soil in compost, sludge, or fuel. I can document many cases of wood scrap recyclers having to send tens of thousands of tons of wood chips to landfills because of treated wood contamination Mr Compost~~~ Jim McNelly~~~ Granite Information Service 612-654-8372-HST 656-0678 v.32bis jim.mcnelly@granite.mn.org Newsgroups: rec.gardens Subject: Re: Pressure Treated Lumber (YIKES) From: heffron@falstaff.css.beckman.com (Matt Heffron) Date: 19 Jan 1994 11:32:20 -0800 >>I read an article in Organic Gardening...a couple months ago, >>can't find the issue right now...that said more nasties DO leach >>out of PT wood than the industry would like you to know. The "more than the industry would like you to know" phrase was Schooder's, it's not in the article. >How much is more than we would like to know? Is it 1 ppb, 5 ppb or is it >a ppm? It looks like the numbers are in the low ppm to very high ppb range. (They aren't directly stated but can be inferred from other numbers in the article.) > I don't want to defend the wood products industry, but in my >experience, OG isn't known for their absolute quantitative accuracy. How >much can leach out before we need to be concerned vis a vis all the other >pollutants we expose ourselves to everyday? I've typed in some excerpts (about half) of the Organic Gardening article, attached below. I'm glad I haven't built my raised beds yet. Matt Heffron - Excerpts from the Organic Gardening article: "TREATED WOOD: Yes, it's still toxic!" by Cheryl Long and Mike McGrath (Jan 94, pp 71-74) Recently, a Texas count extension agent pronounced pressure-treated wood safe to use in raised bed gardens. Newspapers, industry magazines such as _Nursery News_, and even another major American gardenign magazine all reported this finding not only as truth, but as the final word on the subject. ...Many readers have written to ask if we have changed our opinion on treated wood and/or to comment on this new report from Texas. No, we haven't changed our opinion and that Texas report was not a true scientific study. It was a half thought-out experiment conducted by a local extension agent and an extension vegetable specialist after gardeners in their region became concerned following our reports about the dangers of using "pressure-treated" wood (which is actually made with two heavy metals and arsenic, not "pressure" as the companies that produce this stuff would like you to think). Anyway, these two guys took 15 soil samples from raised bed gardens framed with CCA (chromated copper arsenic) treated wood and had them tested. Despite the fact that two different labs found measurable amounts of arsenic in every instance, these two rocket scientists still concluded that the tests had somehow "confirmed that arsenic was not leaching from the timbers." ...In a _real_ study, the arsenic levels found in the treated-wood soil would have been compared to the amount (if any) of arsenic found in similar soil that wasn't surrounded by treated wood. All they _can_ say for sure from their limited testing is that there was definately arsenic in every soil sample taken near treated wood. How they determined that the arsenic did not come from the treated wood is beyond us. ... We, on the other hand, have continued our research on "pressure-treated" wood and are even _more_ convinced than ever that this stuff should not be used in organic gardens. Here are excerpts from some of the additional scientific studies we've reviewed recently: * "This study suggests that leaching of metals from treated wood in acidic waters (natural or resulting from acidic precipitation) _[Editor's Note: acid rain]_ may present an unacceptable environmental risk...Leaching of metals from weathered wood found to be very similar to that from new wood...Results from this study suggest that organic acids may cause greater leaching from CCA-treated wood than mineral acids...Organic acids are present in...soils, bogs and wetland areas." -- Warner and Solomon, _Environmental Toxicology and Chemistry_, 1990 * "It has been shown that organic acids may cause significant leaching of all components of CCA...CCA-treated jack pine blocks exposed to vegetable compost had greater leaching losses (12 to 13 percent CCA leached) than matched samples in distilled water (4 to 6 percent leached), exterior weathering (2 to 8 percent) or exterior soil burial (1 to 6 percent.)" -- Cooper and Ung, _Forest Products Journal_, Sept. 1992 ... * "Even after two years of exposure to rain and snow, the leaching of chromium, copper and arsenic from CCA-treated wood roofing is too high to allow collected water from such roofing to be used as drinking water according to the Norwegian requirements." -- Evans, International Working Group on Wood Preservation, 1987 * "The amount of arsenic alone that leached from a 2-by-2-inch piece of wood in one week in our studies is enough...to kill a mouse...Just think how much is being leached from piers and bulkheads." -- Sanders, Academy of Natural Sciences of Philadelphia, 1991 ... Once again: The simple truth is that _there is no question that chromium, copper and arsenic all leach from treated wood--even the treated wood industry itself admits that much._ ... Garn Wallace, Ph.D., a biochemist at Wallace Laboratories in El Segundo, Calif., who with his fater has been studying the effects of heavy metals on soils and plants for over 20 years, explains that levels as low as _1 part per million_ soluble arsenic (which is equal to about 20 ppm "total arsenic") have been reported to be toxic to some plants. ...Unfortunately, he explains, "the organic acids in compost greatly increase the solubility of arsenic." When we asked Dr. Wallace his opinion of the Texas "CCA is Safe" report, he stated that some of the arsenic levels they reported finding could be toxic to plants and added that "if these levels were found in my garden, I would definitely be concerned _and_ I sould certainly avoid eating root vegetables grown in those soils." (Arsenic accumulation in plants occurs mainly in the roots.) New data shows that even _very_ low levels of arsenic in drinking water can cause severla kinds of cancer; and so the EPA is currently deciding how much to _lower_ the currently limit of 50 parts per _billion_ for arsenic in drinking water. (That's right--the "harmless" levels found in soil by the Texas guys were hundreds of times higher that the levels that the EPA is now saying are too high for water.) ... We have now cited two dozen scientific studies and government reports that document the dangers of arsenic and the leaching of all three toxins from treated wood. Send us a stamped, self-addressed envelope and we'll send you a list if you want to look them up yourself. ... So what should _you_ do next time somebody tells you treated wood is safe? Take a simple cotton cloth--say their handkerchief--and rub it over a piece of treated wood; a raised bed timper or a piece of playground equipment that a child may touch a hunderd times in an hour. Show the person that cloth and explain that it now has detectable levels of arsenic on it. Who says? Both American (U.S. Consumer Products Safety Commision) _and_ Canadian (Health and Welfare Canada and Geological Survey of Canada) government researchers who performed this simple "wipe test" themselves on treated-wood playground equipment of varying ages. They never failed to find arsenic on the cloth afterwards. Matt Heffron heffron@falstaff.css.beckman.com Beckman Instruments, Inc. voice: (714) 961-3128 2500 N. Harbor Blvd. MS X-10, Fullerton, CA 92634-3100 I don't speak for Beckman Instruments unless they say so. Newsgroups: rec.gardens From: segura@owlnet.rice.edu (Chad James Segura) Subject: Re: Pressure Treated Lumber (YIKES) Date: Fri, 21 Jan 1994 19:38:22 GMT |> * "Even after two years of exposure to rain and snow, the |> leaching of chromium, copper and arsenic from CCA-treated |> wood roofing is too high to allow collected water from such |> roofing to be used as drinking water according to the |> Norwegian requirements." |> -- Evans, International Working Group on Wood |> Preservation, 1987 I wouldn't drink water from any roof of any type. |> * "The amount of arsenic alone that leached from a |> 2-by-2-inch piece of wood in one week in our studies is |> enough...to kill a mouse...Just think how much is being |> leached from piers and bulkheads." |> -- Sanders, Academy of Natural Sciences of Philadelphia, |> 1991 Enough to kill a mouse, but in what concentration. Pure? |> Once again: The simple truth is that _there is no question |> that chromium, copper and arsenic all leach from treated |> wood--even the treated wood industry itself admits that |> much._ They do? Of course, there is some leaching, but it is the amount that matters and not that it does. |> Garn Wallace, Ph.D., a biochemist at Wallace |> Laboratories in El Segundo, Calif., who with his fater has |> been studying the effects of heavy metals on soils and |> plants for over 20 years, explains that levels as low as |> _1 part per million_ soluble arsenic (which is equal to |> about 20 ppm "total arsenic") have been reported to be |> toxic to some plants. ...Unfortunately, he explains, "the |> organic acids in compost greatly increase the solubility of |> arsenic." |> |> When we asked Dr. Wallace his opinion of the Texas "CCA |> is Safe" report, he stated that some of the arsenic levels |> they reported finding could be toxic to plants and added |> that "if these levels were found in my garden, I would |> definitely be concerned _and_ I sould certainly avoid |> eating root vegetables grown in those soils." (Arsenic |> accumulation in plants occurs mainly in the roots.) |> |> New data shows that even _very_ low levels of arsenic in |> drinking water can cause severla kinds of cancer; and so |> the EPA is currently deciding how much to _lower_ the |> currently limit of 50 parts per _billion_ for arsenic in |> drinking water. (That's right--the "harmless" levels found |> in soil by the Texas guys were hundreds of times higher |> that the levels that the EPA is now saying are too high for |> water.) That amount in soil is not the same as that amount in water. I do not eat soil. |> We have now cited two dozen scientific studies and |> government reports that document the dangers of arsenic and |> the leaching of all three toxins from treated wood. Send |> us a stamped, self-addressed envelope and we'll send you a |> list if you want to look them up yourself. And were there any which you ignored, because their findings didn't match your conclusions? |> So what should _you_ do next time somebody tells you |> treated wood is safe? Take a simple cotton cloth--say |> their handkerchief--and rub it over a piece of treated |> wood; a raised bed timper or a piece of playground |> equipment that a child may touch a hunderd times in an hour. |> Show the person that cloth and explain that it now has |> detectable levels of arsenic on it. Who says? Both |> American (U.S. Consumer Products Safety Commision) _and_ |> Canadian (Health and Welfare Canada and Geological Survey |> of Canada) government researchers who performed this simple |> "wipe test" themselves on treated-wood playground equipment |> of varying ages. They never failed to find arsenic on the |> cloth afterwards. Chad Newsgroups: rec.gardens From: ajh@diamond.idbsu.edu (Andrew Huang) Subject: Re: Pressure Treated Lumber (YIKES) Date: 23 Jan 94 13:14:19 Chad James Segura) writes: I wouldn't drink water from any roof of any type. In Bermuda, you have no choice. Building codes _require_ the inclusion of cisterns that collect rain water from the roofs for domestic use. That amount in soil is not the same as that amount in water. I do not eat soil. Yes, but your children and their friend do. And if you garden, you will get it on your skin, which turns out to be a good way to absorb As. And were there any which you ignored, because their findings didn't match your conclusions? Don't needle the poster - the posting was clearly marked as an excerpt from Organic Gardening. -andy Newsgroups: rec.gardens Subject: PT Lumber From: jim.mcnelly@gcbb.granite.mn.org (Jim Mcnelly) Date: Tue, 25 Jan 94 00:40:00 +0600 Organization: Granite City Info Center 612-654-8372 hst 656-0678 v.32bis This message was originally addressed to Karen Ann Woodfork and a carbon copy was sent to you. ---------------------------------------- Karen wrote; >I don't need to be convinced not to put arsenic in my back yard, >but I was wondering if you could give me the references for those >facts and figures you gave about the hazards of PT sawdust and >the eventual disposal problems of PT wood. My source(s) include the Minnesota Pollution Control Agency Hazardous Waste Section, the tests of the Benton County Solid Waste District (Foley Minnesota), and independent laboratory analysis conducted under the supervision of the MNPCA. I have also provided several samples to independent laboratories on my own and have confirmed the arsenic and lead levels. The 21 dead cows were verified by the State Veterinarian, actually ordered to be destroyed by him due to the diagnosis of arsenic poisoning and arsenic in the milk. The cases of humans overcome by arsenic smoke I have from conducting an electronic search of various national newspapers for the word "arsenic". You can imagine sifting through the reports on the reported poisoning of President Zachary Taylor and reviews of various presentations of the play, "Arsenic and old Lace". The EPA standards on arsenic levels in compost and sludge are from the EPA 503 sludge rules (11 PPM vs 3000 PPM in PTwood) which are published in the Federal Register and available from your regional EPA office. The toxicity reactions of arsenic, symptoms, and treatment are from any good medical encyclopedia, my copy from toxicity reference documents used at the Mayo Clinic here in Minnesota. You can also find a copy of "Arsenic, Chromium, and Copper Poisoning form Burning Treated Wood" in "The New England Journal of Medicine" June 2, 1983 which reports the effects of arsenic poisoning in a family exposed to burning arsenic (treated) wood in the fireplace. According to the three doctors at the University of Wisconsin, the family had "symptoms of conjunctivitis, bronchitis, pneumonia, sensory hyperesthesia of the arms and legs, muscle cramps, dermatitis of over the arms and legs and soles of the feet, nosebleeds, ear infections, blackouts and seizures, gastrointestinal disturbances, and severe alopecia." "Investigation revealed the presence of high amounts of arsenic in the hair of the parents (12 to 87 PPM; normal less than .65) levels in the fingernails 100 to 5,000 ppm; normal .9) Samples of dust in the home revealed levels of arsenic up to 2,000 ppm." You can look at an article called "The Phone Poles that Will Not Die" from "MSW Management" Nov/Dec 1992. Check also "Env Pollution" 14.213 26 by C. Grant and A.J. Dobbs "The growth and metal content of plants grown in soil contaminated by a copper chromium arsenic wood preservative". I also have references (Woodson 1971, Chisolm 1972, Hess and Blanchar 1977) that arsenic at 2500 PPM is a complete soil sterilant and that sensitive plants show phytotoxicity from 1 PPM to 50 PPM if the arsenic is in an extractable form. Arsenic reacts with plants being substituted for phosphorous (Asher and Reay 1979) and its effects can be limited by supplemental applications of phosphate. I would like to try to >convince someone not to use any more of the stuff for picnic >tables and the like and I need cold hard facts! I believe that it is nearly impossible to convince people of the biohazard of treated lumber, which is the major reason why I am calling for its removal from public use. They seem to refuse to believe that the words "treated" or "pressure" means arsenic, or believe that arsenic is indeed a poison. People simply want to believe that since the product is at the lumber yard, it is the same as regular lumber. One neighbor I tried to keep from burning scraps insisted that the wood was "salted" and that salt was "OK". KAW>I had always been concerned about the problem of leaching because >of the O.G. articles, but now I am more concerned about the vast >quantities of this stuff being used for non-gardening structures >- >(kids jungle-gyms, decks, etc.) .... I need to convince my >neighbor not to put the scraps in the "burn pile" - There is an architect named Cameron Duncan who has led a "one man" fight against treated lumber in school play equipment. He has been intimidated, threatened, slandered, and has had lost business as a result of his efforts. There has been virtually no support for his efforts aside from the National Coalition against the Misuse of Pesticides, which will provide information at a fee. Their number is 202-543-5450. KAW>Your help is greatly appreciated! >-Karen I am taking the liberty of posting this note on the public conference. Mr Compost~~~ Jim McNelly~~~ Granite Information Service 612-654-8372-HST 656-0678 v.32bis jim.mcnelly@granite.mn.org --- * January 24th - I may not act wisely, but at least I act. Newsgroups: rec.gardens From: griff@ole.cdac.com (Mark Griffin) Subject: Pressure treated lumber repost Date: Thu, 15 Apr 1993 07:24:17 GMT Lines: 151 This is a repost of an article I read a while ago on this subject that seemed so well documented that it was hard to ignore. I got tweaked into reposting it after reading someone getting flamed about using good 'ol CCA40 by a bozo that seemed to not take much of anything seriously. Hope it helps whoever requested it. griff@cdac.com ---------------------------------------------------------------------- This was posted in misc.consumers.house a while ago. ---------------------------------------------------------------------- >From: bellas@ttidca.TTI.COM (Pete Bellas) Newsgroups: misc.consumers.house,sci.med,misc.kids Subject: Re: Hazards of arsenic in pressure-treated wood used in play equipment Date: 9 Aug 90 17:58:28 GMT Organization: Citicorp/TTI, Santa Monica >A group of us are building a playground set and the use of pressure-treated >wood had been suggested. I recall a that demonstrated health hazard existed do >to the arsenic and chromium compounds used, both from physical contact of wood >surfaces and from subsequent leaching of arsenic and chromium-containing into >the immediate soil. My concern is that small children, playing on the >playground set, would most certainly come into contact with these compounds, >may put fingers into their mouths, or have snacks without washing up prior to >eating. > >I'm looking for papers and, or other info in the scientific literature which >discusses this issue. I'm proposing to use untreated wood, but to finish it >with a high quality wood preservitive, such as Thompsons. I'd like to present >my case from a position of substantive knowledge. The most common preservatives are creosote, pentachlorophenol and inorganic arsenic salts. The first two are sold as paints for home application, while the third is used primarily in commercial "pressure treated" wood. The terms pressure treated and preserved seem innocuous enough, but the chemicals involved are potent pesticides formulated to repel termites, bacteria and fungi for decades. Although homeowners want their playsets to last, the thought of children playing on poisoned wood is repugnant. It is not surprising, then, that as wood gained popularity as a play structure materiel, preservatives came under close scrutiny. The chemicals are practical and convenient, but are they safe? Ultimately all preservatives pose some risk, although the health hazard varies from potentially serious to negligible. Creosote, the smelly black goo that is smeared on railroad ties and telephone poles is the oldest industrial wood preservative and has been in use for almost 150 years. In laboratory animals it causes skin irritation, cancer and genetic damage; in humans, it has been linked to skin cancer and causes eye and skin irritations, dermatitis and burns. It remains potent for years, moving easily through the wood to affect the soil - and the skin and lungs of anyone who touches it or breathes its vapors. Pentachlorophenol (PCP) is a cleaner alternative to creosote, but is equally suspect from a health standpoint. A member of the same chemical family as 2,4,5-T, it contains dioxins and has caused cancer and birth defects in laboratory animals as well as short term effects such as skin, eye, nose and throat irritations. It is easily inhaled and absorbed through the skin and continues to give off toxic vapors for as long as seven years. The EPA controls the use of both PCP and creosote and recommends sealing any wood that has been contaminated by these preservatives with two coats of urethane, shellac or latex epoxy enamel (shellac is inappropriate for play structures for it is slippery when wet). The pressure treated wood sold in lumber yards is preserved with inorganic arsenic compounds, either chromated copper arsenic (CCA) or ammoniacal copper arsenate (ACA). CCA was developed by Karl Hienrick Wolman in 1913 (hence the term Wolmanized) and has been used for 50 years as an inexpensive alternate to creosote. Associated with rats and lace trimmed old ladies diabolically doing in unsuspecting boarders, "arsenic" strikes a note of uneasiness in most people, but it is a common element in the environment. The form of arsenic used in treated wood is the pentavalent state - the same that is found in shrimp, mushrooms, rice and sardines. In laboratory animals, inorganic arsenic compounds can cause cancer, birth defects and genetic mutations, as well as headaches, dizziness and muscle spasms. But, unlike PCP and creosote, the arsenic preservatives bind tightly to the wood fibers. Studies show that the chemicals do not migrate to the surrounding soil and plant tissue and are not absorbed through human skin. The EPA concluded that pressure treated wood is "safe for frequent contact because absorption through the skin is negligible." The preservative sometimes leaves a bloom of chemical residue on the lumber, and while children cannot absorb the arsenic by directly touching it, their fingers often end up in their mouths. To assess this danger, the California State Department of Health conducted a study in which researchers repeatedly licked their hands after rubbing them over treated wood surfaces. After several days of testing, their urine showed no increase of arsenic even though the measuring device was sensitive enough to detect the effects of a single sardine. The authors of `Evaluation of Risk to Children Using Arsenic-Treated Playground Equipment' concluded that kids have as much chance of getting skin cancer from the CCA-treated play equipment as they do from playing in the sun. CCA is probably more of a health risk to parents than to their children since minute amounts of preservative laced sawdust may be inhaled or swallowed during construction. Wear a dust mask when sawing or machining arsenic-preserved wood, and do the work outdoors to avoid contaminating indoor air with preservative dust. Because incineration of treated wood releases arsine, an extremely poisonous gas, wood scraps should never be burned; bury them or take them to an approved dump site. Pressure treating the wood does not inject preservatives right to the core of the lumber; thus, drilled or cut surfaces have to be brushed with at least two coats of liquid preservative. Wear rubber gloves during these applications, avoid dripping the chemical on plants, and wash hands thoroughly after any skin contact to remove any residue. After the structure is built, hose it down with soap and water to remove any surface deposits of chemicals. Though these three account for the bulk of preservatives sold there are alternatives: low toxicity preservatives such as copper and zinc napthanate, copper-8-quinolinolate, polybase, bis[tributyltin]oxide (TBTO), and TBTO/polybase. These are not known carcinogens, are not herbicidal or poisonous in the concentrations used for preserving wood and are relatively stable. All effectively prevent damage from mold, mildew and rot by keeping the wood dry enough to discharge fungi and bacteria. Copper napthanate, the active ingredient in Cuprinol, has been on the market the longest (1948). Often used to treat lumber for greenhouse growing beds, copper napthanate is the only one of the above chemicals rated to withstand constant ground contact. Because it can be difficult to paint over and must be reapplied if the wood cracks, it is better to use copper napthanate below ground, and use zinc napthanate or one of the other water-repellant finishes above ground. These chemicals are not, however, sufficient to protect wood against termites. Termites feast on copper napthanate as readily as they do cedar, leaving CCA treated wood as the only alternative for areas with termite problems. I hope this has helped. -Pete- References: California State Department of Health - "Evaluation of Risk to Children Using Arsenic-Treated Playground Equipment' Canadian Institute of Child Health - "Moving and Growing" Home Playgrounds - Merilyn Mohr - Camden House Disclaimer:These are solely the opinions of the author and in no way reflect the opinions of Citicorp or it's management. *Batteries not included, void where prohibited, discontinue reading if a rash develops. * Pete Bellas "Cogito ergo spud" * * Citicorp/TTI I think therefore I yam. * * Santa Monica, CA * * Path:{philabs|csun|psivax}!ttidca!bellas or bellas@ttidca.tti.com * | "Never trust a man who doesn't play golf." | ---------------------------------------------------------------------------- ...........................griff@ole.cdac.com................................ From: jim.mcnelly@hal9k.ann-arbor.mi.us (Jim Mcnelly) Newsgroups: rec.gardens Subject: Re: raised beds Date: 16 Mar 93 16:33:00 GMT Organization: HAL 9000 BBS, W-NET HQ, Ann Arbor, Michigan, USA Reply-To: jim.mcnelly@hal9k.ann-arbor.mi.us (Jim Mcnelly) To: daoffer@ccwf.cc.utexas.edu (Debora Offer) From: jim.mcnelly@hal9k.ann-arbor.mi.us Date: 15 Mar 93 12:38:40 DO>rd Lauria) writes: DO> >I am planning to build some raised beds for my garden. It seems DO> >smart to use pressure treated wood to protect from rot, but it seem DO> >I remember seeing something awhile back that this was bad because DO> >the chemicals could leach into the soil and then into the plants. DO> > DO> >Is this true? What have others done? Not use PT wood? Line the DO> >bed with plastic? Pressure treated lumber, or Cromated Copper Arsenate, CCA contains over 3000 PPM arsenic and over 1000 PPM lead. The EPA sludge rules set the acceptable limit for arsenic at 11 PPM and lead at 250. While it is generally true that arsenic does not leach out of properly treated wood, the sawdust is rarely vacuumed and disposed and it can run off into surface water and permanently contaminate the soil. Improperly treated wood can contain live aresenic crystals and the brochure that is SUPPOSED to be handed out every time any CCA treated wood is sold warns about contacting the wood with skin, as arsenic is a severe carcinogen, notably for skin cancer. The info can be acquired from the Treated Wood Assn at 800-241-0240. The scraps should NEVER be burned as both fumes and ash are highly toxic. Currently, there is NO acceptable disposal option for treated lumber, and the product does eventually decompose, leaving its metals in the soil. Jim the Compost Man~~~~~ . SLMR 2.0 . ASCII to ASCII, DOS to DOS... . QNet3. . * * ORIGIN: GRANITE BBS * St. Cloud MN * 612-654-8372 HST | HAL 9000 BBS +1 313 663 4173 or 663 3959 | Four 14.4k v.32bis dial-ins | | Public Access QWK-to-Usenet gateway | With PCBoard 14.5aM & uuPCB | | Member of EFF, ASP, & ASAD | 1.5 Gigabytes Online | Service since 1988 | Newsgroups: triangle.gardens From: crsc@math.ncsu.edu (CRSC Account) Subject: Re: Cold Frame Materials Question Summary: Don't use treated wood! Date: Tue, 14 Dec 1993 14:20:15 GMT > Does anybody know what the considerations are for choosing a >type of wood to use for a cold frame (that will be used for vegetables)? > I am interested in what preservatives can be used on the >wood, if any, that won't cause a problem leaching into the soil or with >fumes being absorbed by the plants. Is treated wood ok? Is it ok to >use varnish? What can I put on untreated wood that would be ok? Check out the latest copy of Organic Gardening for the most thorough discussion I've yet seen regarding the use of pressure-treated wood for gardening. Although they didn't discuss alternatives in this article, (I think they did in an article earlier in the year) I won't be using treated wood in any projects in my garden unless they will be completely sealed - painted or waterproofed. They cite research that shows that contact with acidic organics like compost, speeds the leaching of the chemicals into the soil. One of the chemicals involved is arsenic; it can be absorbed by plants and is particularly concentrated in the roots. I don't know if varnish is ok for plants, but it probably would be a good way to seal the wood and prevent chemical leaching. For other possible wood to use, you might consider cedar (I think it has similar properties to redwood, which is about the only wood used in outdoor projects in CA). -- Lisa Becker Newsgroups: rec.gardens Subject: Is CCA PT lumber OK for a From: jim.mcnelly@gcbb.granite.mn.org (Jim Mcnelly) Date: Sat, 9 Apr 94 13:06:00 +0600 Organization: Granite Information Svs. 612-654-8372 hst 656-0678 v.32bis Here is my FAQ on Arsenic Lumber, and in another post, the product safety sheet that is *supposed* to be handed out to every purchaser of the product which was a part of the EPA agreement to allow the product to be sold. Additional information on CCA, Chromated Copper Arsenate. The wood has been tested by the Minnesota Pollution Control Agency, Hazardous Waste section to be over 3000 parts per million arsenic. The EPA limit on arsenic in sewage sludge for unrestricted use is 11 PPM. There is at least one case of 24 cows dying from eating ash from CCA wood ash in MN and several cases in other states. There is another case of arsenic poisoning in a Wisconsin family from a backdraft in their fireplace while burning treated wood. Arsenic is associated with hair loss, diarrhea, asthma, skin cancer and other skin disorders. Particular caution should be exercised if the wood has a white, gritty residue on the surface, as these may be arsenic crystals. Penetrating oil stain may slow down weathering of fibers and reduce arsenic surface residues. The exposed ends of boards are more likely to leach arsenic than the rest of the board. The wood should be resealed every two years. Of particular concern is sawdust left at construction sites that can he ingested by children, pets, or become exposed to the skin. Runoff of sawdust into ponds, pools, wells and gardens is another concern. Arsenic is rated by the EPA as a class A carcinogen, the top level of risk. Children "mouthing" the wood are also at risk, especially the board ends that release twelve times the arsenic of the rest of the wood. This is especially a concern as arsenic treated wood is a common component in playground equipment. Tests for arsenic beneath children's play equipment have run as high as hundreds of times above background levels. Treated wood is also a problem in disposal. While such a broad range biocide such as CCA retards decay, it does not stop it. Estimates of rot resistance of 20 to 50 years are common. The wood will *eventually* decay, and with the sawdust and ends from construction, will have to go somewhere. The treated wood industries have lobbied to have CCA treated wood exempted from hazardous waste designation through a de-listing procedure that is still unclear. The product is currently allowed to be sent to conventional and demolition landfills. It is often burned with other wood wastes and is commonly chipped into landscape mulch or compressed into toxic fuel pellets. It releases toxic fumes and ash in house fires, putting neighbors and firefighters at extra risk. The ash from a burned CCA patio deck is not managed as the hazardous material it is. The argument from the treated wood industry has been that the arsenic does not leach from the wood fiber under normal soil conditions. While this is somewhat true, it is misleading. The wood will _eventually_ decay and leach its metals and there is currently no safe disposal. The practice of burning wood scraps and the mismanagement of the wood both residentially and commercially has resulted in airborne arsenic levels increasing nationwide, especially in the major cities where scavengers burn scrap wood for heat. Most uses of the wood such as decks, fences, and stakes are not necessary for such extreme wood treatment. Only in the Southeast is the potential of climate high in promoting decay. There is no need for treated wood at all in the west, except on the northwest coast. Because of these concerns, but primarily due to the threats of the wood to commercial organic wood recycling, I am recommending that the product only be sold or used by licensed and trained professionals, similar to other hazardous pesticides, and that it be banned from non-hazardous land disposal sites. Mr Compost~~~ Jim~ McNelly ReSourceNet and GardenNet 612-654-8372, 656-0678 v.32bis jim.mcnelly@granite.mn.org * April 9th - A bird in the hand craps on the wrist. Newsgroups: rec.gardens Subject: Wolmanized deck wood sap From: jim.mcnelly@granite.mn.org (Jim Mcnelly) Date: Sun, 5 Jun 94 12:16:00 +0600 Organization: Granite City Connection St. Cloud MN 612-654-8372 TK>Not exactly a gardening question, but maybe someone can offer a suggestion. >Our 1.5 yr-old deck recently started oozing sap from the knots in the wood, >which is pressure-treated Ponderosa Pine. Has anyone experienced this probl I get a kick out of the term "Wolmanized". It really means "impregnated with toxic levels of arsenic and lead with copper and chromium thrown in for good measure but we will call it something useless like "wolmanized" so people don't scream in horror when they buy it". TK>before? Can anything be done about it? One guy at the local hardware store >said it was fairly common, just part of the wood-seasoning process, and ther >was nothing to do but wait until all the sap come out, which might take a >year. Any advice appreciated. The guy at the hardware store is a useless source of information about hazardous materials in your backyard. He (she?) has little more than the "product data sheet" which is *supposed* to be handed out with *every* arsenic laced piece of lumber they sell. The fact that it is leaching toxic goo is a sign that you and your family are being exposed to skin cancer producing levels of arsenic in your own back yard from a product that is supposedly "non-leaching" of arsenic. The real story behind arsenic treated wood, which is what it SHOULD be called, is that chemical companies have gobbled up vast stands of southern pine forests and are impregnating it with arsenic levels 300 times the limit set by the EPA for the beneficial use of compost on farm land. Rather than kiln dry and cure the wood, they pressure treat it and get a price twice that of ordinary pine. They then launch a dis-information campaign touting the "non-leaching" properties of this green (in more ways than one) lumber claiming that it is "safe". Your testimony about sap leaching out is clear evidence that this cheap pine masquerading as long lasting lumber is a cruel hoax that is a part of the doubling of skin cancer rates over the past twenty years. What can I say? You and millions of other consumers have been duped and you are now exposed to hazardous levels of arsenic in the sap. I don't know which is worse, the sap leaching out poisoning children, the decks burning and poisoning the people down wind, the arsenic in the water where the wood is impregnated, the arsenic in the un-lined demolition landfills, or the householders decades from now when the rest of the leaching arsenic is leaching into their gardens. The product should be banned in my opinion. I can' believe that the rest of the environmental movement has been asleep about this problem. "Sap leaching is common". I could cry. Mr Compost~~~ Jim~ McNelly Granite Connection 612-259-0801 jim.mcnelly@granite.mn.org --- * June 4th - Get your modem runnin, Head out for the Highwaves! From shenkm@BCC.ORST.EDU Date: Wed, 5 Oct 94 08:02:05 CST From: Myron Shenk To: london@sunsite.unc.edu Subject: Forwarded message... Larry, FYI, here is my response I sent Dr. Clark yesterday. Myron Shenk ----- Forwarded message begins here ----- From: Tue, 4 Oct 94 15:50:06 CST To: ACLARK@CROP.UOGUELPH.CA Subject: Re: Query: risk of contamination from pressure treated wood Dr. Clark, I recently saw an article on the consequences of using pressure treated wood around landscapes and gardens, in which they concluded that there is very little danger from such. You should contact: Dr. Alan Schreiber Washington State University Pesticide Coordinator 100 Sprout Road Richland, WA 99352-1643 Phone 509/375-9462 FAX: 509/375-9460. Sorry, I do not have an e-mail address for Alan. Cheers. Myron Shenk ------ Forwarded message ends here ------ Myron Shenk (503)737-6274 Internet: shenkm@bcc.orst.edu IPPC Cordley Hall, Rm 2040 Oregon State University Corvallis, Oregon 97331-2915 From RPE8105@acs.tamu.edu Date: Thu, 6 Oct 1994 10:26:14 -0400 From: Richard Egg To: london@sunSITE.unc.edu Subject: Query: risk of contamination from pressure treated wood (fwd) ------------ Forwarded Message begins here ------------ From: "Richard Egg" Date: Thu, Oct 6, 1994 9:22 To: sanet-mg@ces.ncsu.edu Subject: Re: Query: risk of contamination from pressure treated wood In message <10D02B3507C7@csnet.nw.uoguelph.ca> "E. Ann Clark, Associate Professor" writes: > Friends: I am passing on the request of a friend regarding the risk, > if any, of using pressure treated wood as edging for a garden. Ann, There was an article/essay in Organic Gardening in 1993 or early 1994 (I think) concerning using treated wood near gardens and as playground equipment. The essay criticized a news release by a member of the Texas Agricultural Extension Service that claimed that there was no harm, and then went on to cite a couple of major studies that showed definite leaching effects and uptake, especially by root crops. The studies are cited in the article. I have the article at home somewhere in a stack of magazines in need of organizing, and will attempt to find it this weekend. However, an electronic library search might find it quicker. Richard Egg Agricultural Engineering Department Texas A&M University College Station, TX 77843 (409) 845-7686 r-egg@tamu.edu ------------ Forwarded Message ends here ------------ Richard Egg Agricultural Engineering Department Texas A&M University College Station, TX 77843 (409) 845-7686 r-egg@tamu.edu From CGRIFFIN@KSUVM.KSU.EDU Date: Thu, 6 Oct 94 12:48 CDT From: Charlie Griffin To: SANET-MG@ces.ncsu.edu Subject: Re: Query: risk of contamination from pressure treated wood Regarding the question about pressure-treated wood: There's a woodworker's list that has periodly discussed this issue in detail. I've been off that list for some time now, but you might consider subscribing to WOODWORK@IPFWVM.BITNET long enough to ask there for the best update, or doing a search of their FAQ's and archives. They've been quite detailed in their discussion. Hope it's helpful. Charlie Griffin cgriffin@ksuvm.ksu.edu Article 3938 of alt.sustainable.agriculture: Newsgroups: alt.sustainable.agriculture Path: bigblue.oit.unc.edu!concert!rutgers!dziuxsolim.rutgers.edu!uunet!haven.umd.edu!darwin.sura.net!news.duc.auburn.edu!aces17!aces20.acenet.auburn.edu!mshelby From: mshelby@acenet.auburn.edu (Mark E. Shelby) Subject: Pressure treated lumber Message-ID: Sender: news@acenet.auburn.edu Nntp-Posting-Host: aces1 Organization: Alabama Cooperative Extension Service, Auburn University Date: Wed, 5 Oct 1994 19:12:05 GMT Lines: 112 Post to alt.sustainable.agriculture Subject: Pressure treated wood >On Wed, 5 Oct 1994, Lawrence F. London, Jr., wrote: > >On Tue, 4 Oct 1994, E. Ann Clark, Associate Professor wrote: >> >> Can you advise on: >> a) what chemicals are present and leachable from the wood (e.g. >> arsenic..) >> b) what rate of leaching is likely to occur in a humid, >> temperate, winter cold region >> c) direct us to any documented evidence of bioaccumulation of >> said chemicals in domestic vegetable and fruit crops? >> > >Could those of you responding to the above request >send me any information you may have. I have compiled a FAQ on >pressure treated lumber for the folks in the rec.gardens and >alternative healthcare newsgroups. We would greatly appreciate any >additional data on this topic, especially feedback on item c), bio >-or- hyperaccumulation in fruits and vegetables. > >My FAQ is at sunSITE.unc.edu in the following directory: >pub/academic/environment/pesticide-education/faqs >the file is: pressure-treated-lumber.faq (72kb) > >Many thanks. >________________________________________________ >Lawrence F. London, Jr. - london@sunSITE.unc.edu >------------------------------------------------ > I also had questions about pressure treated wood because as an Extension Agent I deal with home gardeners all the time. There was an independent study done by Dr. Calvin R. Finch, Bexar County, Texas Extension Agent, on whether the chemicals used in pressure treated lumber leached into the soil. I will reproduce the text of his letter here: June 20, 1994 Dear Agriculture and Horticulture Agents: If your situation is like mine in San Antonio, your constituents have a large number of questions about CCA treated landscape timbers. "Organic Gardening" Magazine has declared the inexpensive, easy-to-use timbers as unsafe to use for raised bed vegetable gardens. The pronouncement put me in quite a quandary because our youth programs in San Antonio have 6,000 children gardening on raised beds every week. We have rocky, heavy soil and the only way to grow a good garden is in raised beds. The Environmental Protection Agency does not restrict the use of CCA treated timbers for vegetable gardens. People are frightened, however, of arsenic (a component of CCA, along with copper and chromium) even though it occurs naturally in every living organism and soil. Some work that I did as a demonstration supports the conclusion that the materials are safe. We collected 12 soil samples, six inches deep and one inch from the timbers in six gardens of various ages. Two labs analyzed the arsenic level in the soil samples; levels between 1.1 and 14 ppm were detected. Three other samples from the interior of the gardens showed similar levels. Since the level of arsenic that naturally and safely occurs in soils is between 1 and 20 ppm, I was reassured. To enable you to draw your own conclusions about this important issue, I encourage you to send a self-addressed, stamped (52 cents) envelope (6" x 9 1/2") to CCA Treated Timbers, 1143 Coliseum Rd. San Antonio, TX 78219. I will send you the results of the demonstrations we did on CCA treated timbers and used railroad ties, and a summary of the literature that both sides of this issue are using to draw their conclusions. Sincerely, Calvin R. Finch, Ph. D. County Extension Agent-Horticulture Bexar County, Texas I received a copy of his demonstration results and literature, and after examining them for myself, I agree with his conclusions. Additionally, there is also some literature available from the American Wood Preservers Institute, most especially a publication called "Answers to Often-Asked Questions About Treated Wood". I have also received this publication and have found it to be quite useful and thorough in its coverage of issues concerning treated wood, from industrial to regulatory to consumer concerns. This publication is no-holds-barred and deals very realistically with the issue. This publication is available by mailing to: "Often Asked Questions" c/o ABJ Marketing 1323-C Shepard Drive Starling, Virginia 20164 or by calling 1-800-533-1843 Good Reading! Mark Shelby "All opinions expressed are strictly my own and do not reflect the opinions of the Alabama Cooperative Extension Service." Article 3940 of alt.sustainable.agriculture: Newsgroups: alt.sustainable.agriculture Path: bigblue.oit.unc.edu!concert!inxs.ncren.net!taco.cc.ncsu.edu!lll-winken.llnl.gov!sol.ctr.columbia.edu!howland.reston.ans.net!agate!darkstar.UCSC.EDU!news.hal.COM!olivea!sgigate.sgi.com!sgiblab!pacbell.com!amdahl!netcomsv!ix.netcom.com!netcom.com!geof f From: geoff@netcom.com (Geoffrey Leach) Subject: Re: Query: risk of contamination from pressure treated wood Message-ID: Organization: NETCOM On-line Communication Services (408 261-4700 guest) References: <10D02B3507C7@csnet.nw.uoguelph.ca> Date: Wed, 5 Oct 1994 20:02:17 GMT Lines: 26 ACLARK@CROP.UOGUELPH.CA (E. Ann Clark, Associate Professor) writes: >Friends: I am passing on the request of a friend regarding the risk, >if any, of using pressure treated wood as edging for a garden. Over the last few years, Organic Gardening magazine has published several items on this subject. Need I say tht they do not approve of using "pressure treated" lumber (yes, its arsenic)? They also don't approve of recycled RR ties; the creseote is a problem too. You will no doubt discover that the issue is quite contentious. There are lots of folks who scoff at their concern. They also report a significant effort on the part of the industry that produces the stuff to debunk their findings, although somehow that effort seems to be devoted more to PR than science. My $0.02 ($0.36 CDN) is that I don't want my veggies growing anywhere near something with arsenic in it. But then, I wierd. Regards, -- Geoffrey Leach C/C++/X11/Motif/OpenLook Implementation geoff@netcom.com Mountain Ranch Software 3351 Alma St., Suite 113 Palo Alto 94306 415-855-9788 From RPE8105@acs.tamu.edu Date: Mon, 10 Oct 1994 10:41:30 -0400 From: Richard Egg To: ACLARK@crop.uoguelph.ca Cc: london@sunSITE.unc.edu, sanet-mg@ces.ncsu.edu Subject: Re: Query: risk of contamination from pressure treated woo Ann, The article on pressure treated wood for use near garden crops and playground equipment was in the January, 1994 issue of Organic Gardening. Richard Egg Agricultural Engineering Department Texas A&M University College Station, TX 77843 (409) 845-7686 r-egg@tamu.edu Article 4146 of alt.sustainable.agriculture: Path: bigblue.oit.unc.edu!oit-mail2news-gateway From: lwiggert@netcom.com (Lara Wiggert) Newsgroups: alt.sustainable.agriculture Subject: Re: Query: risk of contamination from pressure treated wood Date: 24 Oct 1994 14:44:09 -0000 Organization: sustag-public mailing list Lines: 29 Sender: daemon@bigblue.oit.unc.edu Distribution: world Message-ID: References: <10D02B3507C7@csnet.nw.uoguelph.ca> NNTP-Posting-Host: bigblue.oit.unc.edu Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Ms. Clark, Regarding your treated wood query, the EPA has several publications on the topic of wood preservation which discuss toxicity - I just glanced at one we have at hand, and it mentions cadmium, chromium, copper and zinc as heavy metals used in this type of process. Also, you may want to look for a CD-Rom database called Environment Abstracts at your University library - this is a popular database and many schools subscribe to it. It is possible to log onto the EPA's online library system for yourself (brochures explaining how to do this are available), or, you could submit an information request to us, as we handle questions from outside the U.S. Our contact information is as follows: INFOTERRA/USA EPA Headquarters Library/3404 401 M St., SW Washington, D.C. 20460 202-260-5917 FAX: 202-260-3923 Sending a fax is recommended so that we will have your complete contact information and details of your information needs. Lara Wiggert Reference Librarian INFOTERRA/USA Article 63733 of rec.gardens: Path: bigblue.oit.unc.edu!concert!gatech!howland.reston.ans.net!cs.utexas.edu!math.ohio-state.edu!hobbes.physics.uiowa.edu!cobra.uni.edu!klier From: klier@cobra.uni.edu Newsgroups: rec.gardens Subject: PT Wood Info from Michigan Extension Message-ID: <1995Apr13.053050.41641@cobra.uni.edu> Date: 13 Apr 95 05:30:50 -0500 Organization: University of Northern Iowa Lines: 54 From: Michigan State University, Cooperative Extension Service. MSU COOPERATIVE EXTENSION FACT SHEETS Number 5 1990 USING TREATED WOOD AROUND THE GARDEN The most commonly available treated wood is impregnated with a combination of chemicals known as CCA (chromated copper arsenate). This is sometimes known by its trade name, Wolmanized wood. The chemicals protect the wood from attack from agents, such as fungi, which can shorten the useful lifetime of the wood. Since these chemicals can have toxic effects at high enough levels of exposure, there is concern about using CCA-treated wood around gardens where these chemicals might contaminate fruits and vegetables that are eaten by the growers. From what is presently known about this type of treated wood, the risk of such contamination is low. First, the chemicals are forced into the wood at very high pressure and remain effectively bound to the wood for very long periods of time. Only very small amounts of these chemicals leak out and get into the soil. Second, these elements (i.e., arsenic, chromium, copper) do not move very rapidly through the soil so migration is limited. Movement from treated wood would not be expected to cause a significant increase in the normal background levels of these elements (commonly found in all soils) except within 6 inches of distance from this type of wood. Plant roots growing within 6 inches of treated wood could be expected to take up higher levels of copper and arsenic than would occur in similar soil located greater than 6 inches away. The significance of this increased uptake depends on several factors (e.g., plant species, volume of soil in close proximity to treated wood, soil fertility conditions, etc.) and is difficult to predict. Due to the general unavailability of chromium from soils, no increase in plant uptake of this element would be expected. Overall, the potential for contamination of vegetables and fruits by CCA is very small and any residues would be at levels far below those known to cause toxic effects. However, if the gardener wishes to reduce this potential even further, barriers can be used. For example, if this wood is used for a raised bed, the inside of the wood can be lined with heavy duty plastic. Another possibility in this and other situations is to coat the wood with an appropriate sealer. In general, these steps are not necessary but they may be used to provide an extra margin of safety. Author: Michael A. Kamrin Institute for Environmental Toxicology Michigan State University  X-Within-Url: http://sulaco.oes.orst.edu:70/0/ext/extoxnet/techinfo/mk_nl5.asc