Jill Greenberg for TIME

Cross posted from TIME’s Healthland

Plastics. They seem so…inert. Slow to erode or decay, with a biodegradation time measured in the hundreds of years, plastics appear cut off from the organic environment in the way that no other product is, safe and secure and sterile. Yet scientists have begun to learn that plastics are anything but impermeable. Plastic containers and linings—especially those used in food containers that might end up being heated or washed—often leach chemicals into the surrounding environment. And some of those chemicals—like bisphenol-A (BPA) and phthalates—may do strange things to the body, mimicking and disrupting hormones in ways that haven’t yet been fully understood.

While the science over such “endocrine disrupting” chemicals is still far from certain, enough researchers have raised worries that some parents have begun avoiding some plastics in an effort to shield children from toxins. (Pregnant women and infant children seem especially vulnerable to endocrine-disrupting chemicals.) Manufacturers have even begun advertising some products as “BPA-free.”

Beijing might have the right idea, because it may turn out that endocrine-disrupting chemicals like BPA are even more common than we imagined. In a new study for the journal Environmental Health Perspectives, researchers found that most plastic products leach endocrine-disrupting chemicals—and that was true even for products labeled “BPA-free.” Scientists led by George Bittner, a neurobiologist at the University of Texas, looked at 455 common plastic products and found that 70% tested positive for estrogenic activity. Once those products were subject to real-world conditions—microwaving or dishwashing—that proportion rose to 95%. As the study concluded:

Almost all commercially available plastic products we sampled, independent of the type of resin, product, or retail source, leached chemicals having reliably-detectable EA, including those advertised as BPA-free. In some cases, BPA-free products released chemicals having more EA [endocrine activity] than BPA-containing products.

BPA is particularly worrisome simply because it is so common. Nearly every American has some amount of BPA in their body, in part because plastics are so ubiquitous. (And the U.S. seems to be especially contaminated—a recent study found that Americans have twice as much BPA in their body as Canadians.) The Food and Drug Administration expressed “some concerns” last year about the potential impact of BPA on the brains of fetuses, infants and children—but no federal agency has yet said that BPA or any other potentially endocrine-disrupting chemicals are unsafe.

Washington may be reluctant to act, but other authorities are moving forward. Cities and states including Connecticut and Minnesota are working to restrict BPA in baby products, while even China—not exactly a country on the forefront of environmental protection—is reportedly planning to ban BPA in children’s products. Even some corporations are moving faster than federal regulators on chemical safety—Wal-Mart announced last month that it had banned the polybrominated diphenyl ethers (PBDE), a class of flame retardants that has been linked to a number of health problems.

Just because some big companies are moving ahead on chemical safety doesn’t mean that industry as a whole is ready to be a leader—a spokesman for the American Council on Science and Health, an industry-funded lobbying group a watchdog with a history of skepticism towards chemical safety, criticized Wal-Mart for giving into environmentalists. In any case, there should be no doubt that our chemical regulations lag far behind the science—the Toxic Substances Control Act, the decades-old law that governs chemical safety, doesn’t give the government sufficient enforcement powers. Industry likes to talk about promoting “science-based” regulation. Based on the conclusions of studies like this one, I couldn’t agree more.

More from TIME on chemical safety:

The Perils of Plastic