More than 83,000 chemicals go into solvents, cosmetics, and other American products, but no one knows how the vast majority of them affect our health. For the Environmental Protection Agency, screening a single chemical can take years and cost millions. The agency has ordered testing on just 200 compounds and restricted or banned only five since it gained the authority to regulate new chemicals in 1976 under the Toxic Substances Control Act. (Among the banned substances are polychlorinated biphenyls, or PCBs, which can cause cancer and liver dysfunction.)
Now, after 35 years of criticism for lax oversight, the EPA is adopting a new technology that promises to put some teeth into the 1976 law. In March the agency introduced a $4 million, six-ton screening robot called Tox21 that is on track to test 10,000 chemicals over the next two years for just a few hundred dollars each, says EPA biologist Bob Kavlock. To pick out potentially harmful substances, the robot first loads samples of 1,400 chemicals at 15 different concentrations onto a set of plates. Then it plunks the plates into a device that adds cells modified to glow if a chemical interacts with them. After a 24-hour incubation, the robot identifies which combinations are aglow so that researchers can perform further testing.
The EPA has even launched a website to share results from Tox21 and other screening tests. Bisphenol A, an ingredient in plastics that mimics estrogen and has been linked to breast and prostate cancer in mice, is among the first batch slated for screening. Says Kavlock, “There’s tremendous payoff every direction you look.”