More than a decade after cosmetics industry experts declared the products unsafe, the Food and Drug Administration has proposed a ban on hair straightening products that contain or emit formaldehyde.
Frequent use of chemical curling irons is associated with a possible increased risk of developing uterine cancer, also known as endometrial cancer. A woman who uses the product often faces more than twice the risk of her non-users.
Other studies have linked curling irons and hair color to breast and ovarian cancer. The agency's scientists determined formaldehyde is a human carcinogen seven years ago, and agency attorneys began drafting a proposed ban at the time.
Workers such as embalming workers who are exposed to high levels of formaldehyde have higher rates of myeloid leukemia and other rare cancers. The FDA warns that immediate reactions may occur, including eye and throat irritation, coughing, wheezing, and chest pain. Chronic or long-term problems include frequent headaches, asthma, skin irritation, and allergic reactions.
Hair straightening products are primarily marketed to black women. Although the incidence of uterine cancer has increased in recent years for all women, the increase has been most pronounced among women of color, including women of Asian and Hispanic descent.
The agency's proposed rule would ban formaldehyde and other formaldehyde-releasing chemicals from hair straightening and hair smoothing products sold in the United States. The target date for the ban is April 2024.
Although some treatments, such as so-called keratin treatments, claim to be formaldehyde-free, they contain a substance called methylene glycol, which converts to formaldehyde gas when exposed to air. (Scientists think of methylene glycol as simply formaldehyde in solution.)
The FDA previously has the power to ban certain ingredients, such as formaldehyde, and has removed about a dozen ingredients from cosmetics, including mercury compounds.
But until last year, when Congress gave the FDA oversight authority, the industry was largely unregulated. However, the FDA said this action is not related to new authorities.
Expanded oversight does not mean that new products are normally subject to regulatory review before being sold to the public. But manufacturers of products like shampoo, nail polish and cosmetics now have to register their manufacturing locations with the FDA and are required to disclose ingredients on their packaging.
The FDA can also issue mandatory recalls of cosmetic products if serious health concerns or deaths occur.
The controversy surrounding formaldehyde in curling irons has been going on for years. The advocacy group Environmental Working Group petitioned the agency in 2011 to ban hair products containing formaldehyde, and again in 2021.
FDA lawyers began drafting rules for the proposed ban in 2016, but the process abruptly halted several months later with no explanation.
“FDA has known for decades that these products are dangerous,” said Melanie Benesch, vice president of government affairs at the Environmental Working Group. “There's no reason they didn't take action sooner.”
“This is the first time we've seen any public indication that they plan to ban its use in hair straightening products,” Benesh added. These products pose a real risk of harm, both to hairstylists who are regularly exposed to formaldehyde vapors when providing treatments, and to the clients receiving them, she said.
The agency is now encouraging consumers to read the labels of hair products before purchasing them and avoid products containing formaldehyde, formalin and methylene glycol. The agency urges consumers to ask hairdressers about the products they use and report any side effects.

