Before this plastic enters the natural ecosystem, the chemicals inside can leach out of water bottles and other food containers, entering the body and potentially endangering human health, according to a mounting body of research. In particular, plastic contains endocrine-disrupting chemicals (EDCs) that could wreak havoc on certain messaging systems in the human body.

EDCs cover a vast family of substances that include many synthetic industrial chemicals such as bisphenols, flame retardants, per- and polyfluoroalkyl substances (PFAS), or “forever” chemicals, and phthalates, among others.

They’re found in everything from electronics to carpets and paints to cosmetics—and in plastics. In this material, their applications are broad: phthalates are known as plasticizers and give many plastics their flexibility and durability, whereas PFAS have nonstick qualities that come in handy in the production of molds for plastic products—and leave behind a telltale chemical residue that can migrate into whatever substance the plastic goes on to contain.