The U.S. Food and Drug Administration has proposed a ban on the use of formaldehyde in hair relaxers over concerns about its link to respiratory problems and certain cancers.

Right now, the FDA only discourages using such hair-straightening products, which are typically used by Black women.

Recent research has helped raise awareness about the potential dangers of using chemical hair relaxers.

“We know that these products are very poorly regulated by the federal government in terms of what goes in there,” said Kimberly Bertrand, an associate professor of medicine at Boston University School of Medicine and the lead author of a recently published study on the dangers of relaxers. “You can’t look at an ingredient label and know that it contains these endocrine disruptors. They don’t list phthalates and parabens on the box — they say fragrance and preservative. So, women don’t really know what they’re being exposed to.”

In that study, data from Boston University’s Black Women’s Health Study, which began in 1995 and tracks the health of 59,000 Black women, showed that postmenopausal Black women who used chemical hair straighteners had a higher risk of developing uterine cancer, NBC News reported.

Another study published recently by the American Journal of Epidemiology found lower fertility in current and former users of hair straighteners.

Women who used hair-straightening chemicals more than four times in the previous year were more than twice as likely to develop uterine cancer, according to a study published last year by the U.S. National Institutes of Health.

A number of cosmetics companies, including Revlon and L’Oréal, have also faced lawsuits over claims that their straightening products have led Black women to develop uterine and breast cancer, infertility and other health issues, NBC News reported.

Formaldehyde is a colorless, flammable, highly toxic gas. It’s used in a variety of household products, including medicines and cosmetics, according to the U.S. Centers for Disease Control and Prevention.

It is linked to myeloid leukemia, according to the U.S. National Cancer Institute.

The FDA has proposed establishing the ban in April.

More information

The Agency for Toxic Substances and Disease Registry has more on formaldehyde.