A recent article in The New Yorker addresses the increasing public awareness into the effects of everyday chemicals on our health, and the inherent uncertainty in determining which substances are safe and which are not. The fact of the matter is that, according to the EPA, roughly 82,000 chemicals are currently registered for use in commerce in the United States, and about 700 new chemicals are introduced each year. Among that number, only 7 percent have undergone a full series of toxicity studies.
The particular focus of The New Yorker article is the difficulty of conducting toxicity studies, and how the inadequacy of the current regulatory system contributes to everyone's confusion. For example, the 1976 Toxic Substances Control Act does not require manufacturers to show that their chemicals are safe prior to their release; rather, the responsibility is instead given to federal agencies and non-governmental researchers (as opposed to the European Union, which now requires manufacturers to prove that their compounds are safe before they are sold). The process of declaring a chemical dangerous or toxic is so mired in complications and red tape that a ban can take years.
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.
As we know, there has been movement towards better and stricter control: in July 2008, Congress passed the Product Safety Improvement Act, which banned six phthalates from children's toys (but BPA removal from other products remains voluntary). Additionally, The President's Cancer Panel report offers strategies to help people, particularly pregnant woman, to reduce their exposure to chemicals and hormones. But clearly more needs to be done.