Polyester. The same synthetic plastic used to weave your favorite pant suit from the 70s has also been implanted in around 750,000 American women – and counting. We’re talking about Essure, the controversial birth control implant that thousands of women blame for horrifying side effects, from severe pain to autoimmune disorders.

Polyethylene Essure Infographic

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Microbeads Banned From US Waters

The Essure implants are two flexible metal coils that can be inserted into a woman’s Fallopian tubes. The core of the device is made from stainless steel and a nickel-titanium alloy, but each implant is also wrapped, inside and out, with fibers of polyethylene terephthalate – the most common type of polyester, according to Quartz. The purpose behind the material’s inclusion in Essure? To force the Fallopian tubes to create scar tissue, a build-up that eventually occludes the organ completely and prevents pregnancy.

If that doesn’t sound bad enough already, consider H.R. 1321, a law passed on December 28, 2015 that banned the “intentional” addition of “plastic microbeads” to any rinse-off cosmetic product sold in the United States. Three guesses on what those microbeads are usually made of. That’s right, polyethelene.

“Inundating Our Oceans”

Microbeads are terrible for our planet, “inundat[ing] our oceans with microplastics that threaten sea birds, turtles and other marine wildlife,” Blake Kopcho, an activist at the Center for Biological Diversity, told EcoWatch in December 2015. Beyond clogging the bodies of fish, microbeads actually suck up other environmental toxins, like pesticides and flame retardants, putting wildlife at even greater risk.

Legislators identified the dangers of plastic microbeads unanimously. H.R. 1321, or the Microbead-Free Waters Act, passed both the Senate and House without one vote of dissent. “Simply put, microbeads are causing mega-problems. Once they’re flushed down the drain, that’s when the problem really begins,” says House Energy and Commerce Committee Chair Fred Upton, a Republican state rep for Michigan.

As a society, we’ve decided that we don’t want this stuff in our lakes, rivers and streams. So why are we letting doctors place it in women’s bodies?

Bottles & Bodies: PET Degradation

PET is derived from crude oil and used most prominently to manufacture plastic drinking bottles.

As an outer coating used to “repel stains or water,” PET works fantastically, says Dr. Margaret Aranda, a graduate of the Keck School of Medicine at the University of Southern California and resident anesthesiologist. But the plastic can also degrade, resulting in some nasty by-products, when exposed to heat or implanted in the body.

Acetaldeyhde & Antimony

On the blog Hormones Matter, Aranda explains:

“The by-products of PET degradation are acetaldehyde, a toxic intermediate in the metabolism of alcohol responsible for much of the liver disease in chronic alcoholics and antimony, a semi-metallic chemical element that is deleterious to health. […] Whether by inhalation or ingestion, acetaldehyde is a carcinogen. Should pregnancy occur in the presence of acetaldehyde exposure, it does cross the placenta and induce skeletal malformations, reduced birth weight and increased postnatal mortality. […] Acetaldehyde is not something one wants leaching into the fallopian tubes, particularly when device placement is incorrect and pregnancy prevention nowhere near 100%.”

Antimony is similarly dangerous, Aranda writes, a topical irritant linked to cell damage and, after continuous exposure, a potential cause of cardiac and hepatic diseases.

Unlike Aranda, many medical researchers aren’t even ready to sign off on polyethylene terephthalate’s use in plastic water bottles. Under “conditions of common use,” PET bottles leach a variety of “endocrine disrupters,” chemicals known to impair the hormone system, into water, juices and condiments. That’s especially true at higher temperatures, according to a lengthy review of the medical literature published in April 2010 by Environmental Health Perspectives.

Enduring Problems

Many say that their symptoms haven’t gone away, even after having the Essure implants removed through a hysterectomy. Now, suspicions have been raised that these lingering side effects are the result of PET fibers, which may remain inside a woman’s body long after her implants are taken out.