We know a lot about bisphenol A, or BPA. More than 200 peer-reviewed studies have linked the synthetic hormone, found in hard plastics and the lining of food cans, to an ever-growing list of health effects. In The Plastic Panic, an expansive article this week in The New Yorker, Jerome Groopman writes that BPA "may be among the world’s most vilified chemicals." So why are federal regulators still undecided about whether to ban it in food packaging? Groopman put the question to John Vandenbergh, a biologist who served on an expert panel of the National Toxicology Program that in 2007 concluded "there is some concern" about exposure of fetuses and young children to BPA:
"Why can’t we just figure this out?" he asked. "Well, one of the problems is that we would have to take half of the kids in the kindergarten and give them BPA and the other half not. Or expose half of the pregnant women to BPA in the doctor’s office and the other half not. And then we have to wait thirty to fifty years to see what effects this has on their development, and whether they get more prostate cancer or breast cancer. You have to wait at least until puberty to see if there is an effect on sexual maturation. Ethically, you are not going to go and feed people something if you think it harmful, and, second, you have this incredible time span to deal with."
Groopman is a rarity among journalists – a physician, a professor at Harvard Medical School and no stranger himself to expert panels that have advised government health agencies. In other words, not someone likely to let the public’s fears about chemicals in baby bottles or soup cans trump sound science. The problem, he writes, is that we may be as close as we can get to a definitive answer about the risks of BPA and similar chemicals:
There is an inherent uncertainty in determining which substances are safe and which are not, and when their risks outweigh their benefits. Toxicity studies are difficult, because BPA and other, similar chemicals can have multiple effects on the body. Moreover, we are exposed to scores of them in a lifetime, and their effects in combination or in sequence might be very different from what they would be in isolation. In traditional toxicology, a single chemical is tested in one cell or animal to assess its harmful effects. In studying environmental hazards, one needs to test mixtures of many chemicals, across ranges of doses, at different points in time, and at different ages, from conception to childhood to old age. Given so many variables, it is difficult to determine how harmful these chemicals might be, or if they are harmful at all, or what anyone can do to avoid their effects. In the case of BPA and other chemicals of its sort, though, their increasing prevalence and a number of human studies that associate them with developmental issues have become too worrisome to ignore. The challenge now is to decide a course of action before there is any certainty about what is truly dangerous and what is not.
Groopman’s conclusion is that while the evidence of BPA’s harm is not conclusive, safer alternatives must be sought, and the nation’s system of chemical regulation must be reformed to give government agencies more guidance about how to act in the face of uncertainty: "There’s no guarantee that we’ll always be right, but protecting those at the greatest risk shouldn’t be deferred."
This article is important because it is perhaps the most highly influential example yet in mainstream journalism of the embrace of the precautionary principle. It follows closely on the heels of the latest President’s Cancer Panel report, a revolutionary document that broke ranks with the medical establishment by declaring that the time is past for asking whether toxic chemicals contribute to cancer, and act on what we already know. That report singled out BPA as the poster child for chemicals that should be more tightly regulated, even as research continues into just how harmful they are. These are encouraging signs; we can only hope they point to a not-distant day when a precautionary approach to chemicals management is accepted for what it is: common sense.