California is introducing new rules for nail products containing triphenyl phosphate, known as TPhP, after the ingredient was linked to several health concerns. The California Department of Toxic Substances Control, or DTSC, has identified nail products with TPhP as Priority Products. Domestic and foreign manufacturers using the ingredient in products sold in the state will need to formally account for its use, justify it, replace it, or remove the affected product from the market.
The rules take effect on October 1, 2026. Nail products containing more than 250 ppm of TPhP must be notified to the DTSC. California’s decision is pushing the nail care sector toward reformulating products without the chemical.
Why TPhP is used in nail products
TPhP is often added to nail product formulations as a plasticizer. It helps improve the pliability and sturdiness of nail coatings and treatments.
Exposure to TPhP has been associated with several health concerns, including liver, endocrine, developmental, neurological, and reproductive toxicity. According to the DTSC, skin contact is the main route of exposure. Inhalation may pose a risk in salon environments too.
Salon workers and their children are considered particularly at risk from exposure.
TPhP has already been prohibited in cosmetic products in the European Union. The prohibition applies under Annex II of the Omnibus II Regulation and has been in place since April 28, 2026.
What the Priority Product status means
A Priority Product designation means a product contains chemicals recognized as presenting a potential risk to human well-being or the environment.
Under the finalized regulation, both domestic and foreign manufacturers must submit a Priority Product Notification, or PPN, by November 30, 2026.
The PPN is a compliance submission required by the DTSC. It formally registers a product as containing a “Chemical of Concern.”
Once a notification has been submitted to the DTSC, nail product companies using TPhP have several routes available.
Companies can conduct an Alternatives Analysis and provide a report to the DTSC to identify safer substitutes. A product may be reformulated to remove TPhP completely, or the ingredient may be replaced with a safer alternative. The final option is to withdraw the product from the California market.
What happens if manufacturers do not comply
A manufacturer that fails to meet the requirements within the required time frame can be added to the DTSC Failure to Comply List.
After the company is listed and a notice has been issued, responsibility for stopping the distribution and sale of the affected nail product in California may shift to importers, retailers, or assemblers.
Nail ingredients face more restrictions
TPhP is not the only nail product ingredient facing tighter rules in global markets.
Trimethylbenzoyl diphenylphosphine oxide, or TPO, has faced bans in several markets. The European Chemical Agency, ECHA, classifies TPO as CMR 1B, meaning it is potentially carcinogenic, mutagenic, or reprotoxic.
Last year, the Moroccan Agency for Medicines and Health Products, AMMPS, announced a ban on TPO in nail products. The announcement came days before the European Union’s ban on the same substance took effect.
The Moroccan ban covers imports, manufacturing, distribution, marketing, and the use of all products containing TPO.
Following Morocco’s ban, Dubai Municipality in the UAE equipped its Central Laboratory with new testing methods designed to detect TPO in nail polish.
