In the study close to 4,500 cosmetic products were inspected for the presence of perfluorooctanoic acid (PFOA) and long chain perfluorocarboxylic acids (PFCAs). The products were inspected by checking the listed ingredients, to replicate the actions of a consumer reviewing the purchase of a product.

Of the 4,500 cosmetic products reviewed, 285 of these contained banned hazardous chemical ingredients. The banned ingredients which were identified were perfluorononyl dimethicone, perfluorooctylethyl triethoxysilane, perfluorononylethyl carboxydecyl PEG-10 dimethicone, cyclopentasiloxane (D5), cyclomethicone (a blend of D4, D5 and D6) and cyclotetrasiloxane (D4).

Perfluorononyl dimethicone is a fluorinated silicone polymer and this degrades into PFOA and PFCAs. PFOA and siloxanes such as D4 and D5 degrade slowly in the environment leading to bioaccumulation in humans and the environment.

These substances are banned for use in cosmetics as they have been identified as persistent organic pollutants or they are defined as (very) persistent, (very) bioaccumulative and toxic (PBT/vPvB). The use of these substances was banned under the Stockholm Convention and restricted under the EU REACH regulation.

In most cases, following written guidance the products in the study found to contain non-compliant substances were removed from the market. Investigations are still ongoing for about half the cases.