Forget "safe" plastics; keep your family's food far away from any kind of plastic wrap or container.

Never mind the number...new research shows any kind of plastic can leach chemcials into your food.

RODALE NEWS, EMMAUS, PA—It used to be that people who just couldn't break the plastic habit to go plastic-free could at least rely on certain types of plastics, usually those labeled #2, #4, or #5 in the triangle of arrows on the bottom, because those plastics weren't made using bisphenol A or phthalates, the two chemicals in plastic that are known to interfere with the way your body produces and handles estrogen. But a new study published in the journal Environmental Health Perspectives concludes that there really are no "safe" plastics, thanks to all the chemicals, additives, and processing aids that go into making plastic products. In a test of nearly 500 chemical containers, the authors discovered that nearly all exhibited some kind of estrogenic activity.

THE DETAILS: The authors purchased 455 plastic products designed to hold food (including plastic bags and baby bottles) that were made from all different types of plastic. Some of the plastics tested, such as high-density polyethylene (#2 in the recycling triangle) and polypropylene (#5 in the recycling triangle), are considered safer plastics because, prior to this study, they hadn't been shown to leach chemicals. Some of the other plastics, such as corn-based plastics and newer so-called "BPA-free" plastic resins, were also tested. All the plastics were filled with substances mimicking food and then subjected to three types of stress—microwave heating, moist heat similar to what they might be exposed to in a dishwasher, and UV light (simulating a water bottle left in a car during the day or a baby bottle being subjected to UV sterilization).

The researchers were able to measure some type of estrogenic chemical leaching from roughly 95 percent of all the plastics tested, including 100 percent of the food wraps and 98 percent of the plastic bags. Even when the plastics were unstressed and just exposed to various solutions, they still leached estrogenic chemicals. And some of the baby and water bottles labeled "BPA free" showed greater estrogenic activity than polycarbonate bottles, which are made from BPA. When they were subjected to stress, the amount of leaching largely depended on what was in the packaging. For instance, some of the highest levels of leaching occurred in plastics containing saline solution when they were put in the microwave; saline is intended to mimic vegetables or other foods with a high water content. But baby bottles containing ethanol, which is intended to mimic milk and other foods with a higher fat content, leached more when exposed to UV light than they did when they contained a saline solution.

WHAT IT MEANS: There really aren't any "safer" plastics, and it's hard to predict which ones will leach estrogenic chemicals into your food. As this study shows, different plastics containing different types of foods will leach chemicals at different levels. That's largely because there are so many steps and additives in the plastic-making process, says George Bittner, PhD, professor of biology at the University of Texas in Austin and lead author of the study. "A plastic item can subsist of anywhere from five to 20 chemicals, some of which are additives, which are incorporated within the plastic polymer but not bound to the structure," he says. Both the materials that make up the plastic resin and the additives can leach out of plastics, says Bittner, who's also the CEO of CertiChem, the lab that tested the plastics in this study, and a consultant for PlastiPure, a company that works with plastic manufacturers to produce estrogenic-chemical-free plastics. You also have mold-release agents and colorants that are used to make or decorate the plastics, adds Mike Usey, CEO of PlastiPure, and those colorants tend to be highly estrogenic.