TCS Daily


Hit the Deck

By Angela Logomasini - April 11, 2003 12:00 AM

If you are considering a new deck, act fast. Federal regulators are poised to ban the most popular and affordable decking material - wood treated with the preservative chromated copper arsenate (CCA). Junk science has indicted CCA, despite the fact that consumers and builders have safely used CCA-treated wood for decades because it resists rotting and pests.

A Consumer Product Safety Commission (CPSC) report released in February claims that CCA-treated wood isn't safe for children because it contains trace levels of arsenic. And the CPSC claims that exposure in childhood might increase lifetime cancer risks for lung or bladder cancer, which occur late in life.

Despite these claims, it is more likely that risks are negligible. CPSC based its conclusions on two National Research Council (NRC) reports (1999 and 2001), on which the Environmental Protection Agency (EPA) based a drinking water rule. These studies assessed risks based on studies of Taiwanese populations exposed for decades to relatively high levels of arsenic in drinking water. CPSC assumed that if long-term exposures increase risk, then short-term ones do the same.

CPSC assumed that exposure to arsenic for a few years in childhood is equivalent to the same total exposure evenly distributed over a lifetime. The NRC (2001) report, however, concluded that cancer risk increases disproportionately with years of exposure, suggesting that the CPSC assumption overstates risks.

There are also serious limitations of using the Taiwanese data. The researchers attempted to determine at what level arsenic poses a risk based on arsenic levels in drinking water wells. Villages included several wells, with a wide range of arsenic levels. Researchers did not know who drank from which wells so they used median arsenic levels for each village. Hence, a village may have had excess cancers from one well that contained high levels of arsenic, but researchers assumed that the cancers resulted from exposures at a lower median level.

Rather than consider how these data limitations exaggerate both EPA and the NRC risk estimates, CPSC moved in the opposite direction. It assumed that arsenic is 6 to 56 times more potent than the EPA's risk estimates.

Do any CPSC assumptions hold up in peer review? We don't know because the CPSC refuses to release the peer review as well as data it used in the study.

CPSC's sloppy research will likely encourage local governments, daycare centers, and others to tear out playground equipment. Perhaps wealthy communities will be able to rebuild, but what about poorer communities? Will kids in poor, inner-city neighborhoods be better off without safe play areas?

CPSC junk science may also advance bans on residential uses of CCA. Last year EPA announced - but has yet to finalize - plans to ban certain residential uses, while asserting that it has not found any "unreasonable risk to the public or the environment." EPA is also considering whether to list CCA-treated wood as a hazardous waste, which could greatly increase disposal costs.

A ban will cost consumers an estimated 20 to 30 percent for wood treated with alternative preservatives - yet costs may be much higher than this estimate. In comments to EPA, one wood processor noted that fence posts made with alternative products cost more than double CCA-treated posts. These new posts are only expected to last 10 years while CCA-treated posts last 30.

In addition, about 350 wood processors would have to retool their shops at a very high price (up to $200,000 each) to make wood with alternative preservatives. Any small business that uses the wood will face steeper repair and replacement costs for various structures as well as increased disposal costs.

People could switch to plastic lumber or hard woods like cedar or redwood. Yet these options are prohibitively expensive for many families and communities, as they can double costs. In addition, regulators might want to consider whether they want federal policy to encourage harvesting of redwood forests.

As prices escalate, many people may keep decks longer - even when decks deteriorate into safety hazards. New decks constructed with alternatives may also pose safety hazardous because alternative preservatives are highly corrosive to screws and nails. As a result, consumers that mistakenly fail to use stainless steel screws and nails may see their new decks eventually collapse. CPSC didn't consider these potential safety perils. In fact, it didn't even consider whether the alternatives were more or less dangerous than CCA.

CPSC is supposed to be our consumer advocate. But if CPSC officials are serious about uncovering threats to consumer safety and choice, maybe it's time they looked in the mirror.

Angela Logomasini is Director of Risk and Environmental Policy at the Competitive Enterprise Institute.
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