Babies can go through thousands of diapers before they are toilet-trained, wearing them nearly around the clock during the first years of their lives. Parents might be surprised to learn that diaper makers aren't required to disclose everything that's in them.
Researchers have detected phthalates and volatile organic compounds in disposable diapers. Independent testing has also found PFAS, the “forever chemicals” that have contaminated drinking water across North Carolina.
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Other testing has identified formaldehyde, dioxins, pesticides and heavy metals. Some substances are intentionally added, while others can enter diapers through raw materials or manufacturing.
“Because of the lack of disclosure, it is difficult to know exactly what is used in diapers, and therefore we may not even know the full extent,” said Sydney Swanson, a senior science analyst with the Environmental Working Group.
Swanson points to potential health concerns associated with some of the chemicals researchers have detected. Certain phthalates can interfere with hormones, some volatile organic compounds have been linked to liver, kidney and nervous system damage, and formaldehyde is a known carcinogen. Fragrances and dyes can also trigger skin irritation or allergic reactions.
That doesn't mean a diaper containing one of those chemicals will harm a baby. Risk depends on the chemical, the amount present, how much can migrate from the diaper and how much actually enters the body.
There is no federal requirement for diaper manufacturers to provide a complete ingredient list. New York now requires ingredient labeling, and a bill advancing in California would require manufacturers to disclose intentionally added ingredients online and on packaging.
North Carolina has no comparable requirement. State lawmakers have instead focused recently on affordability. A bill that passed the state House unanimously this summer would eliminate state and local sales taxes on diapers and baby wipes, along with feminine hygiene products.
What testing has found
PFAS are of particular concern in North Carolina, where contamination of the Cape Fear River and drinking water has led to years of research, regulation and litigation.
Mamavation, a consumer advocacy website, sent 65 diapers and related products from 40 brands to an EPA-certified laboratory. The lab detected organic fluorine, which can indicate the presence of PFAS, above 10 parts per million in 15 products.
Among disposable diapers, six of 35 had organic fluorine above that threshold.
A 2025 study tested diapers and urine samples from 66 infants in China. Researchers detected several phthalates in the diapers and found a correlation between one phthalate in diapers and its metabolite in infants' urine.
They estimated that skin absorption from diapers contributed to infants' overall exposure to several phthalates. Some metabolites were also associated with a marker of oxidative DNA damage.
The study did not establish that diapers caused DNA damage or disease. The authors said more research is needed to understand the potential effects of exposure through diapers.
France's food, environmental and occupational health agency has also investigated disposable diapers. Testing detected substances including formaldehyde, pesticides, VOCs, dioxins and furans. Some appeared to come from raw materials or manufacturing rather than being intentionally added.
The agency found no epidemiological evidence linking diaper use to health effects. Its risk assessment, however, found that safety thresholds were exceeded for some substances under the scenarios it studied and concluded that a health risk could not be ruled out.
Hilary Swank joins push for diaper disclosure
Actor Hilary Swank, a mother of twins, has joined the Environmental Working Group, Consumer Reports and other advocates pushing California lawmakers to require greater disclosure from diaper manufacturers.
“During these precious early years of development, babies absorb everything from the environment around them,” Swank said. “Yet most of the products used during this critical window don't meet the level of transparency or safety that most parents would expect and demand.”
Swank said she began scrutinizing products more closely after becoming a mother and was surprised to learn there is no federal law requiring diaper makers to provide a complete list of ingredients and materials.
“Transparency shouldn't be optional,” she said. “It should be the standard.”
California's Assembly Bill 1901 would require manufacturers to disclose intentionally added ingredients in children's diapers and explain what those ingredients do. The information would be available online and eventually on packaging. The bill would not ban PFAS, phthalates or other chemicals.
Consumer Reports examined ingredient information for 31 disposable diapers and found wide differences in disclosure. Seven provided little to no information about product materials, while only two disclosed all or nearly all of them, according to Oriene Shin, safety advocacy manager for Consumer Reports.
“Parents shouldn't have to be detectives to understand what is in the products that they use on their babies every day,” Shin said.
California Assemblymember Marc Berman, who authored AB 1901, said becoming a father led him to question what was in the diapers his son wore.
“We were using the same diaper brand that we got at the hospital,” Berman said. “I went and looked at the box in our garage, and there wasn't anything on there.”
Diaper industry says products are safe
The Center for Baby and Adult Hygiene Products, a trade association representing diaper manufacturers, says disposable diapers undergo extensive safety testing.
“Diapers are designed and manufactured to meet strict safety standards, and decades of real-world use support their safety for infants and children,” the group said in a statement.
The industry stresses that detecting a chemical does not establish a health risk. Risk depends on factors including concentration, how much of a substance can migrate from a diaper and how much a child actually absorbs.
The trade group says it supports ingredient transparency but has raised concerns about parts of California's bill, including protections for confidential business information.
Supporters say greater disclosure could also push the industry to change.
“When a customer can compare ingredients, manufacturers have an incentive to follow what the consumer wants,” Shin said.
Shazi Visram, founder and president of HealthyBaby, said her company already discloses its diaper materials and supports requiring disclosure across the industry.
“AB 1901 does not ban ingredients. It does not tell companies how to manufacture their diapers. It does not tell parents what choices to make,” Visram said. “It simply gives parents access to information that should have been available all along.”
California's legislation could ultimately matter beyond the state. Required online disclosures could give North Carolina parents access to information that isn't required here. Manufacturers could also choose to use the same packaging nationally rather than produce separate labels for different states.
For parents, the existing research isn't a reason to stop using disposable diapers. Scientists are still working to understand which chemicals can migrate from diapers, how much babies absorb and whether those exposures are enough to affect their health.
For now, the push for disclosure is less about telling parents which diapers to buy than giving them more information to make that decision themselves.