Thursday, February 24, 2011


In 1854, as a cholera epidemic ravaged London, physician John Snow reasoned that it spread via contaminated water. When he created a map of cholera incidence, he discovered that most cases clustered around a public water pump on Broad Street. He talked city authorities into simply removing the pump's handle, and the epidemic ceased. It was soon found that sewage was contaminating the pump's source.

Physicians still avert disease through public health activism, but today they labor mainly in third world countries. In the United States, doctors haven't been taught much about public health; they almost exclusively wait in their offices for sick people to appear.

That leaves the issue to politicians, an abdication tantamount to letting your cat babysit your infant. With few exceptions, politicians have little education in, or even regard for, science.

Take Maine's Governor Paul LePage, for example. He said something truly remarkable yesterday about bisphenol-A, or BPA, an ingredient in plastic bottles. BPA has been identified for decades as a "xenoestrogen," a molecule that, mimicking the female hormone, causes problems in humans, especially in fetuses. 

Here's what Gov. LePage said: "If you take a plastic bottle and put it in the microwave and you heat it up, it gives off a chemical similar to estrogen. So the worst case is some women may have little beards."

Trust me, they won't have little beards, but their kids will be at risk for neurological troubles and feminization. Maybe the Governor would be more concerned if he knew women exposed to BPA might deliver boy babies with small penises.

It's not just his ignorance that disturbs me. He's laughing off the issue, ridiculing people who are justifiably concerned about a dangerous chemical. If he goes on to claim that BPA's never been undeniably proven hazardous, he'll be right, strangely enough. By its nature, science can only show likelihoods, never certainties.

Many chemicals are toxic only in the long run. They can take years to decades to make their effects known. Considering that span plus the fact that thousands of BPA's cousin molecules--in food additives, medications, cosmetics, household products, and outright pollutants--constantly act together on us, their individual culpability is extremely difficult to prove. In terms of liability, these chemicals are a manufacturer's dream.

Americans honor the principle that a defendant is innocent until proven guilty. That's just, but we perversely apply it to chemicals as well as people. Canadians see it differently, employing what they call the "precautionary principle." This legal standard states that if a chemical is suspected, even in the absence of scientific consensus, to cause harm to the public or to the environment, the burden of proof that it is not harmful falls on the manufacturer.

I recently saw a film about the hazards of herbicides. It included an interview with a member of a city council somewhere in Kansas, as I remember, who voted with a majority to ban all herbicide use in that city. He explained, "Look, if I'm right about this, then it's likely several kids won't have cancer twenty-five years from now. If I'm wrong, then there will be a few more dandelions people will have to pick by hand."

One hopes someone educates Governor LePage about values along with basic science. If, as he joked, BPA did indeed cause women to grow little beards, would that concern him, or would he feel it's more important to continue the use of BPA?

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