Scientists warn of toxic 'forever chemicals' in reusable period products

Many reusable menstrual products that have gained increasing popularity among teens are packed with toxic “forever chemicals,” a new study has found.

Among the biggest repeat offenders are washable pads and underwear, according to the study, published on Tuesday in Environmental Science & Technology Letters. And as more consumers opt for multi-use products over their disposable counterparts, the study authors expressed cause for concern.

“Since reusable products are on the rise due to their increased sustainability compared to single-use products, it’s important to ensure that these products are safe,” co-author Marta Venier, an associated professor at the University of Notre Dame, said in a statement.

“This is crucial, especially for adolescents and young women, who are more vulnerable to potential negative health effects,” Venier added.

The compounds in question are known as per- and polyfluoroalkyl substances (PFAS) and are prevalent in numerous household items, such as waterproof apparel, nonstick pans and various personal care products.

There are an estimated 15,000 types of PFAS, all of which are manmade, and some of which have been linked to cancers and other severe illnesses. These so-called “forever chemicals” linger nearly interminably in the environment and up to several years in the human body.

Previous research in China sounded the alarm on the prevalence of PFAS in that country’s personal hygiene products, including in sanitary pads, panty liners, tampons, paper diapers, menstrual cups and bactericidal liquids.

In addition, a 2020 Sierra Magazine article — which included the participation of Graham Peaslee, senior author of the current study — identified “intentional fluorine use” in one type of period underwear, which led to a lawsuit and $5 million settlement with the brand.

To identify PFAS presence in products, scientists typically begin by deploying a broad-stroke screening tool: the assessment of total fluorine in a sample. They generally deem fluorine usage as “intentional” — or deliberate in a product’s formulation, as opposed to accidental contamination — when levels surpass a specific safety threshold.

In the current study, the researchers narrowed their focus on 59 reusable hygiene products — such as period underwear, reusable pads, menstrual cups and reusable incontinence underwear and pads — from North America, South America, Europe, Asia and the Pacific.

The products, they explained, first underwent total fluorine screenings using a technology called particle-induced gamma-ray emission spectroscopy.

These preliminary screenings showed that period underwear and reusable pads likely had the highest rates of intentional PFAS use: 33 percent and 25 percent of items in each of these product categories, respectively.

The findings applied to markets across the globe, with intentional fluorination spotted in seven pairs of South American underwear, four North American pairs and two European pairs, according to the study.

Following the initial fluorine scans, the scientists then chose 19 products for targeted analyses of 31 “ionic” and 11 “neutral” types of PFAS.

Ionic PFAS are those molecules that can “dissociate” in the environment, becoming highly mobile and capable of widespread contamination. Among the most notorious types of ionic PFAS are legacy compounds like PFOA and PFOS, which have largely been phased out of production but remain in the environment due to their persistence.

Neutral PFAS, on the other hand, do not dissociate and were previously thought to be less toxic. But scientists have been challenging that assumption, as these compounds are highly volatile and can serve as precursors for ionic PFAS.

In the more precise PFAS tests for the 19 period products, the researchers detected the compounds in 100 percent of the products, with two types of neutral PFAS — 6:2 and 8:2 fluorotelomer alcohols (FTOH) — boasting the most abundant presence.

Co-author Sydney Brady, a PhD candidate in Venier’s group, stressed in a statement that 8:2 FTOH was one of the most common types of PFAS in the North American items, despite its elimination from food packing by manufacturers.

That phase-out, Brady explained, occurred due to Food and Drug Administration concerns about the chemical’s “persistence in the body after dietary exposure.”

“Notably, 8:2 FTOH can be transformed into more toxic PFOA once inside the body,” Brady warned.

While recognizing that far less research exists on PFAS exposure via skin versus food or water, the authors cited initial studies on dermal absorption as a potentially “significant exposure pathway for PFAS when present in feminine hygiene products.”

“Feminine hygiene products stay in contact with the skin for extended periods of time,” Venier said. “The risks from the dermal absorption of PFAS, especially neutral PFAS, are not well understood.”

As such, the researchers called for further studies to define the risk of PFAS exposure via human skin. In addition, after identifying at least one sample per product category that contained zero intentionally added PFAS, they stressed that safer and healthier alternatives can likely be manufactured without them.