WTC Air Pollution Study Exposed

Air pollution from the World Trade Center collapse caused some pregnant women to give birth to smaller babies, researchers claim.

What’s really going on is that environmental activists are preparing more attacks on President Bush’s proposal for reducing air pollution.

Led by notorious eco-activist researcher Philip Landrigan (search), researchers from the Mt. Sinai School of Medicine reported in the Aug. 6 Journal of the American Medical Association (search) that babies born to pregnant women exposed to air pollution from the WTC were twice as likely to be small for their gestational age than babies born to women who were pregnant during the attacks but not near the WTC site.

Not only is there reason to doubt Landrigan’s results, there’s also reason to doubt his motives.

First, Landrigan’s research methodology is faulty.

Epidemiology, the study of disease rates in human populations, is capable of identifying high risks of rare diseases, such as the approximate 2,000 percent increase in lung cancer risk among heavy smokers.

Though the claimed 100 percent increase in risk of smaller babies caused by WTC air pollution sounds large, in actuality, it is small according to traditional epidemiologic standards. And small-for-gestational age babies are not a rare occurrence, occurring in about 5 percent of births.

Adding another dimension of statistical weakness is the study’s small size, including only 182 babies from WTC-exposed women with only 15 babies deemed small for their gestational age. 

Study participants were recruited volunteers -- not all pregnant women exposed to WTC pollution (search) or even a random sample of such women. Self-selected participants can introduce biases into the study not accounted for by the researchers. The volunteers may have differed in significant but unknown ways from pregnant women who didn’t opt to participate.

The researchers don’t know how much air pollution any of the pregnant women inhaled. This is a fatal flaw since the researchers didn’t measure whether the women who delivered smaller babies were actually exposed to more pollution than the women who gave birth to normal-sized babies.

Air pollution (search) was not biologically determined to be the cause of any of the smaller babies in the study. It’s not even clear that air pollution causes smaller babies -- and therein lies Landrigan’s angle.

Despite Landrigan’s claim in the study and to the media that air pollution is linked with smaller babies, there really is no solid evidence that this assertion is true. Though many researchers have attempted investigate a potential link, the factors affecting birth outcomes are far too numerous and too complex to be easily studied.

Based on research published so far, the most one can say is that if there is a link between air pollution and birth outcomes, it’s too small to measure.

“The most one can say,” however, does not in any way satisfy Landrigan’s eco-activist desire to link birth problems with air pollution -- and more importantly, to link birth problems and other scary health effects with President Bush’s policies on air pollution.

President Bush is now trying to push through Congress his “Clear Skies” (search) initiative to reduce air pollution from coal-burning power plants (search). The plan would set caps on power plant emissions but allow companies to buy and sell rights to emit pollution within those limits.

Environmental activists hate the plan because it’s not their preferred iron-fisted, no-prisoners, totalitarian clamp-down on industry.

The activist group Children’s Environmental Health Network (search)  -- on whose Advisory Board of Directors and Science Committee Landrigan serves -- cries that Clear Skies and other Bush efforts to reduce air pollution “fail to adequately protect children or provide healthy air.”

But that argument is a tough sell without some sort of scientific back-up. That’s why Landrigan is desperately trying to cook up supporting science and publicity wherever and whenever he can -- even if it means shameful junk science exploitation of the Sep. 11 attacks.

Steven Milloy is the publisher of, an adjunct scholar at the Cato Institute and the author of Junk Science Judo: Self-defense Against Health Scares and Scams (Cato Institute, 2001).

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