3.8 Risk assessments help determine safe exposure levels.

When Canada declared its intention to ban BPA from baby bottles in 2008, declaring the substance toxic—a next logical step—was not so easy. That’s because in 2009, the American Chemistry Council launched a formal objection.

By 2008, BPA was already a $3 billion industry unto itself; and, in some cases at least, it had no obvious substitute. That made employing the precautionary principle, or banning BPA more widely, almost impossible. “This is the central dilemma the government faces,” says Lanphear. Government has to keep us safe, and make us feel safe, all without causing a major disruption to the economy. “If the government declared that BPA in all sources was toxic, and it must be eliminated within a year, it would put our economy into a tailspin.” Companies would have to scramble to replace BPA from the myriad of products that contain it.

To make such decisions, we need to know two things: whether a given chemical has the potential to harm us, and how great that harm might be. It’s crucial to consider both. Say, for example, a new study reports that BPA exposure doubles one’s chances of developing a particular disease. Before hitting the panic button, we must first ask what the chances are of getting the disease in the first place, without BPA exposure. If it’s a rare condition, with a 1% probability, then BPA increases our chances to a mere 2%. If it is more common, with, say, a 20% probability, then BPA doubles our chances to 40%—a significantly greater risk. How important that increase is, and thus, what we should do in light of it, depends on the seriousness of the disease.

So, what to do about BPA? Let’s take a look at what we’ve learned so far. We know that chemicals like BPA can have effects at low doses. We know that developing fetuses and young mammals are particularly susceptible to these low-dose effects. We know that BPA is, in fact, leaching into our systems from food and beverage containers, and that it can indeed cross the human placental barrier.

But we also know that BPA is water-soluble and can be excreted in our urine. This means that, in most cases, it may not be building up, or bioaccumulating, in our tissues.

What we don’t know—what we may never know—is how well the effects seen in rodents correspond to the risks faced by humans. And because of all the additive and synergistic effects BPA is likely to have with all of the countless other chemicals we encounter, it will be difficult to tell, even in the future, how much of any given health condition can be specifically attributed to BPA.

The bane of risk assessment is that we can’t really wait for those facts to come in.

In the end, Canada’s federal government decided to declare BPA toxic in 2010, despite the American Chemistry Council’s objections. In announcing the decision, Canadian Minister of the Environment Jim Prentice said: “I am of the view that [the ACC’s] notice does not bring forth any new scientific data or information.”

Soon after Canada declared BPA toxic, the European Union also banned BPA from baby bottles; in 2012, the United States did, as well.

By then, the American Chemistry Council was asking the U.S. government to ban the substance from baby bottles, because manufacturers had stopped including BPA in bottles and sippy cups due to the public’s concern. They weren’t the only industry to voluntarily phase out the chemical—in 2007, outdoor gear and clothing seller Mountain Equipment Co-op, headquartered in Vancouver, was the first Canadian retailer to remove BPA-laden containers from its shelves. That same month, Lululemon Athletica, which sells yoga and running gear, said it would no longer sell plastic bottles that contain BPA. The next year, a host of Canadian companies followed suit—Walmart Canada, Canadian Tire, and Hudson’s Bay Co., among others.

Since declaring BPA toxic in 2010, Health Canada has yet to ban it from anything other than baby bottles and sippy cups, concluding that the amount of BPA in canned food and beverage containers “posed no health or safety concerns to the general public.” Meanwhile, France became the first country to ban BPA from all food containers; its plan will be implemented by 2015.

The purpose of the Canadian ban was to reduce exposures for children, who appear most vulnerable to BPA’s effects, but children do more than drink out of bottles and sippy cups, says Lanphear. Isn’t canned soup a children’s product? “Some important exposures were not considered,” he says. And if children are at risk, should the government consider banning BPA from products that pregnant women come in contact with? Since women don’t always know when they’re pregnant, the ban would have to extend to the packaging of foods that all women eat. And since women generally eat the same things as men, BPA would essentially have to be banned from all food packaging—leading to major disruptions to the economy. But restricting the ban to baby bottles simply “gives us an illusion of safety,” says Lanphear.

However, a widespread ban could create even more problems. Since companies have phased out BPA, they’ve replaced it in many products with a very similar compound: bisphenol S (BPS). Scientists are still studying its properties, but early research suggests it may mimic estrogen more potently than BPA, and break down more slowly in the environment.

“Most of us think that our government is out there, testing these things before they’re released into the marketplace,” says Lanphear. But even in countries like Canada, where the government made that first courageous decision to ban BPA from baby bottles, products are full of chemicals that have unknown effects on the body.

“It may turn out that BPA is perfectly safe, and it may be that some other chemical—flame retardants, or whatever—isn’t,” says Lanphear. “But the point is we aren’t doing these studies on laboratory rats. We’re doing them on ourselves, by releasing these products into the marketplace without knowing their effects. Yet how can we test everything thoroughly without bringing our economy to a grinding halt? This is one of the central ethical dilemmas we’re dealing with in our time.”