Wood Treatment Linked To DangersJan 28, 1998 | Pittsburgh Post-Gazette A forester in Indiana got deathly sick sawing pressure-treated wood to build picnic tables.
Three quarterhorses in Clay County, Fla., fell ill after “cribbing” or biting repeatedly on a pressure-treated wood fence. Two died.
You could pick up more than just a splinter from the chemically impregnated wood widely used to build backyard decks, playground equipment, picnic tables, lawn furniture, fences, gazebos, and boat docks.
The dense, gray-green wood can make you sick, pollute the environment and isn’t as durable as the treated wood industry claims, said Edward Polaski, who compiled a review of research on pressure-treated wood for the state Department of Conservation and Natural Resources.
“My report should be a wake-up call,” said Polaski, who until recently worked for the department as a wood use adviser. “Certainly use of this wood needs more study.”
According to Polaski’s research, chromate-copper-arsenate, or CCA, the highly toxic chemical pesticide widely used as a wood preservative, can seep out of the wood. Those cancer-causing chemicals could pose a health concern and an environmental threat during the wood’s useful life and after its disposal.
Polaski thinks the CCA-treated wood - comprising more than 90 percent of the $2.5 billion a year treated wood market - should be banned or its use severely restricted to areas where people won’t regularly touch it.
But the state Department of Conservation and Natural Resources, the agency that ordered the report, believes Polaski overstates the dangers from CCA-treated wood. The U.S. Forest Service, not to mention the wood industry, is similarly skeptical. And the U.S. Environmental Protection Agency says it is reasonably safe if used appropriately.
But Polaski is not alone in his concerns.
“I don’t think his conclusions are overstated. It’s better to be concerned and conservative before you make the mistake of introducing arsenic into the environment,” said Dr. Garn Wallace, a biochemist at Wallace Laboratory, in El Segundo, Calif. The private lab specializes in plant nutrition, soil composition testing and heavy metals research.
Wallace said liquid oozing from CCA-treated wood could contaminate ground water under porous-sandy soils and produce a host of health problems in humans, from liver and kidney failure to cancers.
Wallace’s studies show arsenic from CCA-treated wood stunts plant growth and turns leaves yellow. Vegetables grown in soil with an elevated arsenic level can contain high arsenic levels themselves. At playgrounds with CCA-treated wood equipment, Wallace has found soil samples showing 10, 20, even 100 times the background level of arsenic in nearby soils.
“It’s obvious from the studies that the growth of herbaceous plants is injured in the presence of CCA-treated wood,” he said. “I don’t know at what levels injuries to people will occur, but there is a plausible risk factor.”
The treated wood industry denies there is a risk if the wood is handled and used properly, and maintains CCA is a safe preservative suitable for structural uses around homes, and in parks and playgrounds.
“There is a 60-year history of CCA in the United States where it has been used successfully,” said Allan Wilbur, a spokesman for the American Wood Preservers Institute. “Of the 160,000 playground accidents that occur annually, none are related to the leaching of those chemicals.”
But a growing number of court cases and jury verdicts have blamed the chemicals for causing harm.
In one case, James Sipes, a U.S. Forest Service worker in the Hoosier National Forest in Indiana, was saw CCA-treated wood to build picnic tables one spring when he got so sick that he vomited up half the blood in his body.
Doctors didn’t identify the cause of his problem until he went back to work. The next spring he was given the same job and he started vomiting blood again. A jury said the chemicals in the wood caused the problems and awarded him $100,000. Twenty-six companies involved with production and supply of the chemicals and wood settled out of court, paying Sipes $667,200.
“The problem with CCA exposure is that you can’t show a history, you could have people getting ill and thinking it’s any number of things - arthritis, the flu,” said David McCray, an Indiana lawyer who has won three claims involving injuries from CCA-treated wood.
“The effects of CCA exposure can be insidious and can range from hair loss, to itching skin, bleeding, nerve damage. Chemical exposure health problems are difficult to pinpoint and can mimic many things.”
Polaski’s report on CCA-treated wood, and another one critical of the state Bureau of Forestry’s fledgling Timber Bridge Program, were done when he worked for the state.
The bridge program, developed to promote use of Pennsylvania hardwoods for small bridge projects, uses the preservative creosote, which is toxic to humans.
The DCNR has disowned both reviews, initiated by Polaski in the early 1990’s with the approval of James C. Nelson, then Pennsylvania’s state forester, to determine if CCA-treated wood is safe. The first draft of the CCA-treated wood review wasn’t completed until June 1994, after James Grace became state forester.
Grace asked the U.S. Forest Service to critique Polaski’s CCA review. In August 1994, Thomas Hamilton, director of the Forest Service’s Forest Products Laboratory, wrote to Grace saying that “although there are some legitimate concerns about the use of CCA-treated wood, [Polaski] overstates the literature and makes assumptions that are not supported by scientific fact.”
“The Forest Service had negative comments and no one has told us his research is valid,” said Gretchen Leslie, a DCNR spokeswoman.
Polaski was fired from the Forestry Bureau job he had held since 1981 in August, four months before his retirement. Polaski said he was let go because of his work on the reports and resulting pressure from the wood products industry, a charge the state denies.
Polaski’s CCA-treated wood report cited studies showing 20 percent, 30 percent, even more than 50 percent of the chemical can “leach” out of the wood. Much of the problem is caused by impure or improperly applied chemicals used in the wood treatment process, causing incomplete “fixing” of the chemicals within the wood.
Studies also show that exposure to acidic rainfall increases the risk of chemical leaching. “Given the acid rainfall in our state,” Polaski said, “the amount of these toxic CCA chemicals leached may increase over time.” Determining the actual leaching rate, however, will require studies of lumber stockpiles and of wood sent to landfills,” he added.
Samuel Rotenberg, a toxicologist at the EPA’s Philadelphia regional office, said the chemical do leach from the wood, but there have been no studies of production conditions and their effects on leaching rates.
He warned that individuals who cut, saw, or sand the wood can be exposed to high levels of toxic chemicals and should protect themselves by wearing a breathing filter over their noses and mouths.
“As far as using a boardwalk or deck built from CCA wood, I don’t think that would present an unreasonable risk,” Rotenberg said. “But I would not build a children’s sandbox out of the stuff because arsenic can leach into the sand and be eaten by children. I also wouldn’t build a sandbox under such a deck because we know now that there can be increased arsenic levels in those areas from sawdust produced during construction.”
Polaski said the high volume of treated wood produced increases potential hazards. More than 50 billion board feet of chemically treated wood has been produced over the last decade at 550 different production plants. About 17 percent of all softwood lumber is pressure-treated today.
Each year, commercial wood treatment infused wood with 137.5 million pounds of chemicals.
John Hall, a spokesman for the American Wood Preservers Association, said that while there are more than 90 standards governing the wood preservative industry and treatment processes, there are none setting acceptable CCA leaching levels.
“There are no standards that specify a level for minimal or maximum migration of chemical pesticides from wood,” Hall said. “Those studies that show a high rate, well, 40 or 50 percent sounds unbelievable.”
CCA-treated wood, first used in India in 1933 and approved by the American Wood Preservers Association for use by Bell Telephone Co. in 1950, is resistant to insect infestation and rot. The copper and arsenic are fungicides and insecticides. The chromium is primarily a “fixing” agent, bonding the chemicals to the wood.
Older wood preservatives - “penta” or pentachlorphenal and creosote - pose considerable health risks to users of the wood, but CCA-treated wood is supposed to be safer in part because the toxins are “fixed” in the wood.
The raw lumber is placed in a pressure cylinder where a vacuum sucks air and water from the wood cells. The cylinders is then filled with a mix of water and pesticides and pressure is increased to refill the wood’s cells with the mixture. As the wood dries, the chemicals are trapped inside.
Arsenic and chromium are carcinogens and mutagens, according to the EPA and the Occupational Safety and Health Administration. Exposure can occur through breathing or through repeated skin contact. High or repeated exposure can cause cancer, fetal toxicity and birth defects, neurotoxicity, including paralysis, warty skin growths, and liver and kidney failure.
Nevertheless, the EPA has certified that CCA-treated wood “does not pose unreasonable risks to children or adults” exposed to the wood or surrounding soils, based on tests of laboratory prepared wood samples conducted in the 1980s.
However, in 1988 the agency was concerned enough about the effects on workers who come in contact with CCA on a daily basis that it required protective clothing and respirators to reduce their exposure.
Polaski said the EPA’s CCA certification tests were invalid because they don’t reflect real and disparate commercial manufacturing conditions. Production of environmentally safe, CCA-treated products involve complex chemical reactions that can be compromised in commercial production, resulting in less than complete chemical “fixing” and increased leaching.
Wilbur concedes that CCA leaching does occur, and it happens more when treatment standards aren’t followed.
“As in any product line, there are good and not so good manufacturers, so [Polaski] has a point,” Wilbur said. “There may be folks that take shortcuts. That’s not appropriate, and we do not condone that, but we have no policing powers.”
Polaski’s CCA research review draws on a number of leaching studies. Among them:
- A 1994 study at the University of Turin in Italy found exposure of CCA-treated wood sawdust to rain water resulted in significant release of the chemicals and was potentially hazardous.
- A 1984 study of the biological impact of CCA-treated wood on honeybees found that the bees had elevated arsenic levels and poorer winter survival when kept in CCA-treated hives.
- A 1991 study by researchers at Rutgers University found leaching of CCA-treated wood in to sea water retarded the growth of fiddler crabs and algae, and resulted in higher death rates for fish and snails.
- The leaching research of David E. Stilwell, an analytic chemist at the Connecticut Agricultural Experiment Station of New Haven, Conn., found elevated levels of copper, chromium and arsenic in soil samples under seven wood decks built with CCA-treated wood.
Stilwell’s 85 soil samples showed arsenic levels two to four times greater than allowable standards, and showed signs of increasing over time. That could harm yard and garden plants.
A playground exposure study he is working on isn’t finished, but thus far indicates that use of CCA-treated wood should be avoided wherever possible in the playground, especially on surfaces children touch regularly.
“If alternative materials are available,” Stilwell said,” why not use them and remove toxic materials away from children’s paths.”
He said sealing the deck or playground equipment retards leaching and minimizes the amount of arsenic that is picked up by contact. It would be even better to replace or cover handrails and play equipment with plastic or a wood-polymer composite like Trex.
His view is supported by the California Health Department, which recommends that play surfaces of recreational equipment be coated every two years with an outdoor-grade polyurethane sealant.
Stilwell also questioned why the EPA requires risk warning stickers of CCA-treated lumber, but not on products such as picnic tables or playground equipment manufactured from the wood.
“There is always the benefit vs. risk question to be answered in these situations and that got lost in the promotion of CCA-treated wood,” Stilwell said. “It’s now being promoted for applications beyond its original scope, and some of those are not a good idea.”
Stilwell concedes that the longer life of CCA-treated wood is reducing pressure to cut endangered trees, such as redwoods. But he said treated wood should either be sealed better or treated with safer chemicals.
One of the biggest selling points for CCA is that it extends the life of wood, saving billions in both dollars and trees.
More than 90 percent of treated wood is yellow southern pine. Without preservative treatment, the wood would only last one to three years, Wilbur said. Wood properly treated with CCA can last 10, 20, even 30 years.
Polaski found, however, that the preservation chemicals sometimes weaken southern soft woods and shorten their lifespans.
“The wood’s structural integrity is attacked by the preservative chemicals, probably the acid in the treating solutions,” he said. “That’s weakening the wood, and certainly, given that many of these decks are built high, creating the potential for disaster if they break.”
Although he admits there are few reports of decks collapsing, Polaski said many built a decade ago are showing signs of decay and should be inspected.
“We’d have to look at that on an individual basis,” said Wilbur, the industry spokesman, “but 99 percent of the deck failures we’ve seen are due to improper construction, not wood failure.”
Disposal and burning of the treated wood creates other problems.
If the treated wood catches fire, Polaski says, smoke from the combustion would contain “copious amounts of poisonous chemicals.” Residual ashes would contain hazardous chemicals that could be absorbed through the skin or leach through soil to contaminate ground water.
In December, Wisconsin’s environmental agency fined John Menard, owner of the 200-store Menard’s home improvement chain, $1.7 million for burning CCA scraps to heat the company’s lumber production facility. Menard was caught carting the ash from that facility to his home, where his disposed of it with the family trash.
In Minnesota, 22 cows were killed when a farmer spread fireplace ashes from CCA-treated wood in the field where they were grazing.
Polaski’s review cites two incidents, reported in 1988 and 1990 newspaper articles, of people harmed by using treated wood for fuel. In both cases, the people developed neurological problems, numbness in the arms and legs, loss of hair, skin rashes and gastrointestinal upsets.
“Burning any of the wood in a fireplace or outside is a bad thought, and presents a clear exposure route to toxic chemicals that should absolutely be avoided,” the EPA’s Rotenberg said.
Despite government and manufacturers’ warnings, the dangers associated with burning CCA wood still aren’t widely known, according to Keith Solomon, a toxicologist at the University of Guelph in Ontario, Canada. His research found that acid rain caused the chemicals to quickly wash out of the wood.
“The public should be better informed,” he said. “While camping, I watched a family at a nearby campsite build a fire with scraps of the stuff. The blue-green flames produced by the chemicals were very attractive, but the kids were cooking hot dogs in the smoke. Not a good idea.”
The recommended method of disposing of construction scraps is by placing them in the trash and taking them to a landfill. That works for now, but what happens over the next several decades, as the decks, fences and docks built in the 1970s and 1980s are replaced and the old wood is sent to landfills?
Based on a 30-year service life, a study by the Forest Products Laboratory in Madison, Wis., estimated that 2.5 billion board feet of treated wood are entering the waste stream today. That will increase to 8 billion board feet by the year 2020.
Landfills owned by Minnesota have already stopped taking CCA-treated wood scraps because of concerns about chemical leaching and water contamination.
“We believe there will be a tremendous problem with CCA disposal in the future. Landfills don’t want EPA-listed hazardous chemicals or know carcinogens,” said Pat Bischel, president of Northern Crossarm Co., a Wisconsin treated-wood producer.
Northern Crossarm last fall stopped making and distributing CCA-treated wood. Instead, Bischel’s firm is now using ACQ - ammoniacal copper quaternary - which contains no hazardous chemicals.
Polaski’s report identifies several safer alternatives, including borate-treated wood, which has been used in Australia and several other countries since the 1940s for bridges, home decking and playground equipment. A half-dozen CCA pressure-treating plants in Hawaii have converted to borates.
Northern Crossarm, Rhode Island-based BB&S, Treated Lumber of New England, and six other wood treatment companies have switched or are switching from CCA to ACQ, a chemical compound produced by Chemical Specialties Inc., one of the nation’s major producers of CCA.
“I believe we will see a transformation of the treated wood industry and within a few years the majority of treatments will use an alternative to CCA,” Bischel said. “CCA won’t be outlawed, but like creosote and penta will be in decline. And like those two treatments, the switch from CCA will be consumer driven.”
Germany banned CCA lumber in the mid-1970s, substituting wood treated with chromium, copper and fluoride. In 1994, New Jersey restricted use of CCA-treated wood in some marine construction to prevent contamination of shellfish beds.
Environmental Building News and the American Institute of Architects both recently recommended that builders consider CCA alternatives.
The nation’s three major producers of CCA have developed their own copper-based alternatives to CCA, each eliminating the most toxic components of arsenic and chromium.
Polaski said a re-evaluation of the safety of pressure-treated lumber by federal and state agencies would hasten the switch to alternatives.
“My intent in compiling information on CCA and related hazardous wood preservatives is not to condemn wood preservatives in general,” he said. “I hope through my efforts, I will encourage the development of reliable, safe wood preservatives.”