In an editorial published in the British Journal of Epidemiology and Community Health, lead author Jane Muncke, PhD, managing director and chief scientific officer of the Food Packaging Forum, writes that these food contact materials pose a “silent challenge to researchers concerned with human health, nutrition and the environment.” More than 4,000 materials are allowed for use in foods sold in Europe and the United States, and synthetic materials are the most problematic. While bisphenol A (a plastic polymer used to line aluminum cans) tends to grab the most scrutiny and attention, it’s far from the only harmful chemical you’re exposed to. For instance, polyethylene terephthalate, otherwise known as the #1 plastics used for bottled water, sodas, and other drinks, contains low levels of formaldehyde. The Food and Drug Administration allows a type of asbestos to be used as a filler in rubber packaging materials. The FDA has also allowed parabens, chemical preservatives linked to hormone disruption and suspected of triggering breast cancer, in food. And those are just the chemicals used intentionally. The commentary also warns against “non-intentionally added substances,” which are impurities and breakdown products from food packaging and from food processing equipment. University of Texas School of Public Health researchers have found high levels of industrial flame retardants in butter, and the suspected source was the equipment used to print the waxed paper wrappers. Experts say that determining the health impacts of all these invisible, but ubiquitous, chemicals is nearly impossible in part because we’re all exposed to them. Even if you minimize your processed food consumption, you might be exposed to chemicals from plastics used to wrap your local farmer’s meat, the plastic bins that hold bulk beans and grains, or the plastics used to line your refrigerator. Whether those levels will harm you is up for debate, though, since even healthy whole foods contain naturally occurring, albeit low, levels of hazardous compounds like formaldehyde. One researcher, Ian Musgrave, MD, a molecular toxicologist at Australia’s Unversity of Adelaide, told the industry publication Food Quality News that someone would have to drink a little over 5 gallons of bottled water stored in #1 plastics to be exposed to the same levels of formaldehyde in a single 3.5-ounce apple. Still, chronic diseases are now the most deadly diseases on the planet, killing more people than infectious diseases than ever before. And teasing out the relationship between all these combined low-levels exposures to food-packaging chemicals and cancer, diabetes, obesity, and inflammatory disorders could be a boon to public health, giving doctors and public health officials one controllable “measureable route of exposure” that might counteract a number of chronic diseases. More from Prevention: The Amazing Packaging-Free Grocery Store