California enacts diaper ingredient transparency by 2029 

USA – California has enacted Assembly Bill 1901, a new law requiring manufacturers of children’s diapers to disclose intentionally added ingredients both online and on product packaging. 

Signed by Governor Gavin Newsom on 28 September 2026, the legislation introduces extensive transparency and labelling obligations for children’s diapers manufactured, distributed or sold in California, with the main requirements taking effect in 2029.

The law applies broadly to children’s diaper products, including disposable briefs, protective underwear, liners, boosters, inserts and underpads intended for children. 

Its purpose is to give parents and caregivers clearer access to information about the materials and substances used in products worn by children.

By 1 January 2029, manufacturers will be required to publish a complete list of all intentionally added ingredients in their children’s diapers on a dedicated webpage on the manufacturer’s website. 

The information may also appear on the relevant product-details page of an online retail website where the diaper is sold. 

For every intentionally added ingredient, the disclosure must include the chemical or raw-material name, its Chemical Abstracts Service, or CAS, number, and the specific function or purpose it serves in the diaper.

The ingredients must be listed in descending order according to chemical or raw-material weight. 

In addition, the ingredient name, CAS number and stated function must appear together, ensuring that consumers can see precisely what each listed substance is and why it is used in the product.

The legislation introduces the packaging obligations in two phases. 

From 1 January 2029, children’s diapers manufactured or distributed in California must include, on the outermost packaging, a publicly identifiable list of intentionally added ingredients as well as the web address of the manufacturer’s dedicated ingredient-disclosure page.

From 1 July 2029, the same information must appear on the outer packaging of all children’s diapers sold in the state.

The earlier January deadline is particularly important for manufacturers, distributors and brand owners. 

Companies cannot treat July 2029 as the only deadline because products entering the California market through manufacturing or distribution channels will already need compliant packaging and disclosure information from the beginning of the year.

The California Department of Toxic Substances Control, or DTSC, will enforce the law and may issue regulations to clarify or implement its provisions. 

Manufacturers that fail to comply may face administrative penalties of up to USD 5,000 for a first violation and up to USD 10,000 for every subsequent violation. 

Where non-compliance continues, penalties may also be applied for each day that the violation remains unresolved. 

California’s law forms part of a wider trend toward diaper-ingredient transparency in the United States. 

New York enacted a diaper-labelling law in December 2024 requiring diaper packages or boxes sold in the state to carry printed ingredient lists in order of predominance. 

That law covers both disposable and reusable diapers.

Illinois subsequently passed its Diaper Labelling Act, which is scheduled to take effect on 1 January 2027. Under the Illinois requirements, packaging for diapers sold in the state must include an ingredient list ordered by predominance. 

Ingredients present at 1% or less may be listed in any order. 

The law also allows manufacturers to use a common or functional name instead of the specific chemical identity when the ingredient qualifies as confidential or as a trade secret under applicable legislation.

Sign up to receive our email newsletters with the latest news updates and insights from Africa and the World HERE.