Bloomberg Law
April 5, 2022, 2:15 PM

Knix Wear Sued Over PFAS Chemicals in Menstrual Underwear

Julie Steinberg
Julie Steinberg

Knix Wear Inc. deceptively touts its absorbent menstrual underwear as free of PFAS, a family of “forever chemicals” known to be harmful to humans and the environment, a new proposed class action alleges.

Gemma Rivera and Marisa Franz say they relied on the company’s marketing statements that the underwear, which collects menstrual fluid, is “PFAS free” and “designed to be both safe and effective.”

Per- and polyfluoroalkyl substances can enter the body through multiple ways including skin contact, according to their lawsuit, filed Monday in the U.S. District Court for the Northern District of California. The Centers for Disease Control and Prevention has outlined “a host of health effects” associated with PFAS exposure, including cancer, liver damage, decreased fertility, and increased risk of asthma and thyroid disease, the lawsuit alleges.

Because PFAS persist and accumulate over time, they are harmful even at very low levels, according to the lawsuit.

PFAS chemical treatments are typically used on textiles to make them water-repellent or stain resistant, the consumers say.

Independent testing found that Knix Wear underwear contains high levels of fluorine, indicating the presence of PFAS, the suit alleges.

There is a growing public health concern about the chemicals used in feminine hygiene products, Rivera and Franz say.

Potential negative health effects stemming from the chemicals in tampons and pads, in addition to environmental concerns related to single-use products, have caused many women to seek out alternative menstrual hygiene products, they say.

Underwear maker Thinx Inc. faces a similar suit in the Central District of California.

The lawsuits are part of a wave of PFAS-related product litigation.

In March, Coty Inc. and its CoverGirl Cosmetics unit were hit with a proposed class action alleging they deceptively market TruBlend Pressed Powder as “sustainable” and “safe” despite the undisclosed presence of PFAS.

L’Oreal USA Inc. faces litigation in the Central District of California and the Southern District of New York alleging that the company didn’t disclose PFAS in mascara.

Colorado recently sued numerous companies that have made firefighting foam containing PFAS or related chemicals. And firefighters in Massachusetts and New York alleged in two separate lawsuits in February that 3M and 23 other companies knowingly made and sold products containing forever chemicals that placed their health at risk.

Causes of Action: California Unfair Competition Law, California Consumer Legal Remedies Act, Song-Beverly Consumer Warranty Act, California False Advertising Law, fraud, misrepresentation, failure to warn, breach of express warranty, Magnuson-Moss Warranty Act.

Potential Class Size: Unknown number of persons in nationwide class and California subclass.

Relief: Declaratory relief; compensatory, statutory, and punitive damages; restitution; injunctive relief; medical monitoring; attorneys’ fees and costs.

Response: Knix Wear didn’t immediately respond to a request for comment.

Attorneys: Bursor & Fisher PA represents the plaintiffs.

The case is Rivera Knix Wear, Inc., N.D. Cal., No. 5:22-cv-02137, complaint 4/4/22.

To contact the reporter on this story: Julie Steinberg in Washington at

To contact the editors responsible for this story: Rob Tricchinelli at; Nicholas Datlowe at