To judge by the scary headlines and news reports, the latest threat to American children comes in the shape of a plastic baby bottle. According to the National Toxicology Program (NTP), Bisphenol A (BPA), which is used in thousands of plastic consumer products, including baby bottles, poses a danger to the health of infants and children.
Supposedly, that is because BPA leaches out of plastic into the blood stream where, even in low doses, it poses a risk to human health. Canada last week declared BPA toxic and Canadian stores rushed to remove anything containing it from their shelves.
Is BPA, in the minute doses consumed by children, really a risk to health? Does the science clearly demonstrate that BPA can harm babies, children or adults? Until the NTP released a preliminary report on BPA last week, the answer was generally no.
There were some scientific studies that suggested even low doses of BPA were dangerous, but the vast majority of studies failed to find a significant and demonstrable risk. In fact, even the NTP report was highly qualified, though you would never know it from the press coverage. The NTP reported that the science raised "some concern" about neural and behavioral effects in fetuses, infants, and children based on "limited" evidence from low-dose studies.
In its review of BPA, the NTP looked at 400 new studies. A mere handful of the studies found a problem with the chemical. In certain instances, a single study was cited to demonstrate harm.
More importantly, none of these studies involved human populations, as all were performed with rodents. Even where they have been studies of health problems in animals exposed to low doses of BPA, there has been no evidence that these effects persist later in life.
Studies and reports from a wide variety of regulatory and safety agencies outside of the United States have given BPA a clean bill of health. A comprehensive risk assessment by the European Union found no convincing evidence that BPA affected development or was carcinogenic. The Japanese Ministry of Environment, which conducted extensive animal tests with BPA, concluded that there was no clear evidence that low doses of BPA had endocrine-disrupting consequences. In addition, German's Institute for Risk Assessment concluded that it did not "recognize any health risk for babies that are fed from baby bottles" containing BPA.
That is because the amount of BPA that babies or children absorb, even under extreme exposure, is well below what toxicologists call the Tolerable Daily Intake (TDI). Norwegian and Swiss researchers found that the amount of BPA that could be extracted from plastic bottles was 1 to 7 micrograms per liter of fluid, compared with the EU's TDI of 250 micrograms per liter of fluid. In fact, the NTP report acknowledges that the exposure levels to BPA that produced behavioral and developmental effects in animals were significantly higher than the levels found in U.S. infants and children.
The harms here are at least three-fold. First, an immensely useful product has been labeled a health menace because of sloppy science. Second, the public has been once again misled, in part by single-issue activists, about the nature and ubiquity of risk. The take-away lesson is that the world is chock full of unknown and significant risks, particularly for children.
Third, and most disturbing for sensible, long-term risk regulation, is that the NTP has capitulated to the precautionary principle bandwagon. As the NTP said, "The possibility that human development may be altered by Bisphenol A at current exposure levels cannot be dismissed."
However, that is equivalent to saying we cannot completely discount the risk the sun will not come up tomorrow. Science cannot prove negatives. We cannot expect science to provide us with absolute assurance.
All we can demand is a reasonable protection from risk. Fortunately, that is exactly what we have with BPA and baby bottles.