A new consumer study tested several brands of bandages and found higher levels of fluorine in bandages from Band-Aid, CVS Health, Walmart, Rite Aid, Target and Curad, which contain harmful levels of “forever chemicals,” also known as PFAS.

The study by Mamavation and Environmental Health News revealed that out of 40 bandages from 18 different brands, 26 contained organic fluorine, an indicator of PFAS.

“Because bandages are placed upon open wounds, it’s troubling to learn that they may be also exposing children and adults to PFAS,” said Dr. Linda S. Birnbaum, the study’s co-author and the former director of the National Institute of Environmental Health Sciences and National Toxicology Program.

News Nation reports that the study found the chemicals present in the adhesive part of the bandages. Mamavation said some brands likely used the PFAS in bandages “for their waterproof qualities.”

“It’s obvious from the data that PFAS are not needed for wound care, so it’s important that the industry remove their presence to protect the public from PFAS and opt instead for PFAS-free materials,” Birnbaum said.

According to the study, the chemicals are linked to several health effects, including “reduced immune system, vaccine response, developmental and learning problems for infants and children, certain cancers, lowered fertility, and endocrine disruption.”

While the exposure risk to PFAS through the skin isn’t clear, skin exposure “poses similar health risks” as eating or drinking food contaminated with PFAS, according to a previous study by the National Institute for Occupational Safety and Health.