It’s used almost everywhere. It’s in almost all of us. It does weird things to rodents and it may be doing weird things to us—but it’s tough to be certain. Bisphenol-A (BPA) has become a litmus test for how people view environmental health and the risks of common household chemicals—as I wrote in a long story for TIME earlier this year. The chemical has countless industrial uses, most often in the epoxy liner of cans and in plastic bottles. But BPA is also an endocrine disruptor, meaning that it has the capacity to mess with our hormones and potentially impact health—especially in developing fetuses—even at relatively low doses. (Because they can mimic hormones—which cause enormous changes in our bodies even at relatively low amounts—the dose-response relationship used to evaluate traditional toxins like lead may not work with BPA.)
Green advocates like the Environmental Working Group have pushed hard to restrict and even ban BPA, citing the potential risk to human health, while industry groups like American Chemistry Council have fought tooth and nail to keep the chemical in use, casting doubt on the animal studies that have shown harm from BPA. In the U.S. so far the result has been something of a stalemate—public worry about BPA is definitely on the rise, especially in the media, and professional groups like the Endocrine Society have raised their own warnings about the chemical, but there’s been no real change in regulation yet from the U.S. government.
Beyond our borders, however, governments are swinging into action. Yesterday Canada—with very little fanfare—declared BPA a toxic substance, both to the environment and to public health. The listing doesn’t mean that all BPA will need to be banned immediately—Canadian officials said that the declaration would be the first in a multi-step process to better regulate BPA. By listing the chemical as toxic, it’s easier for officials to ban the use of BPA in specific products through regulations, rather than amending laws or writing new legislation. Canada has already banned BPA in baby bottles, and this new listing will likely bring an end to food-related uses for BPA, in bottles and possibly cans as well. Here’s an excerpt from the Canada Gazette explaining the decision:
Concern for neurobehavioural effects in newborns and infants was suggested from the neurodevelopmental and behavioural dataset in rodents. Given that available data indicate potential sensitivity to the pregnant woman/fetus and infant, and that animal studies suggest a trend towards heightened susceptibility during stages of development in rodents, it was considered appropriate to apply a precautionary approach when characterizing risk to human health. Therefore, it was concluded that bisphenol A should be considered as a substance that may be entering the environment in a quantity or concentration or under conditions that constitute or may constitute a danger in Canada to human life or health.
The Canadian move was done in the face of intense opposition from the chemical industry, which was quick to respond to the decision. Here’s Steven Hentges of the American Chemistry Council:
Just days after the European Food Safety Authority (EFSA) once again confirmed that BPA is safe for use in food-contact items, Environment Canada’s announcement is contrary to the weight of worldwide scientific evidence, unwarranted and will unnecessarily confuse and alarm the public. This puts Environment Canada at odds with the recent conclusions of EFSA, the U.S. Food and Drug Administration, and the German Federal Institute for Risk Assessment, all of which have concluded that BPA is safe in contact with food. The decision also appears to contradict the very recent opinion of Health Canada, which stated in August that ‘the current dietary exposure to BPA through food packaging is not expected to pose a health risk to the general population, including newborns and infants.
As Hentges points out, the European Union’s own food safety watchdog just issued its own report on BPA, and found no need to change the limit on BPA exposure from food containers. The experts acknowledged that animal studies had found evidence of health impacts on the nervous system and on cancer susceptibility—but they felt that wasn’t enough to prove a risk to human health. Meanwhile in the U.S., half a dozen states have already moved to ban BPA in children’s products, but the federal government still hasn’t taken any action—like the E.U., the FDA has said there isn’t yet sufficient proof of harm in humans. But further studies of BPA are ongoing at the federal level, and Canada’s decision will likely only increase the pressure on the FDA to take stronger action.
So who’s right? As the New York Times put it in a long examination of BPA last month, there’s a lot of data and very few clear answers:
Most of the evidence against BPA comes from studies that find harmful effects in rats and mice at low doses comparable to the levels to which people are exposed. Sometimes the results seem downright weird, indicating that low doses could be worse than higher ones. There is sharp disagreement among scientists about how to interpret some research. The disputes arise in part because scientists from different disciplines — endocrinologists versus toxicologists, academic researchers versus those at regulatory agencies — do research in different ways that can make findings hard to reconcile.
The biggest unanswered question is whether low doses — the kind to which most people are exposed — can have lasting, harmful effects in fetuses and young children. Dr. [Linda S.] Birnbaum, [director of the National Institute of Environmental Health Sciences, part of the National Institutes of Health], said it was crucial to find out for sure whether the low-dose effects in animals really occur. “We have hundreds of studies that show they do, and then some that don’t,” she said.