Using analysis of existing scientific literature and opinions from European Union and French risk assessment agencies, experts classified ingredients or groups of ingredients into three categories: high risk, moderate risk and low or not identified risk.
WECF found that three ingredients or ingredient families it considered high risk are in 299 of the products. These include methylisothiazolinone, a contact allergen; perfume or fragrance, which may involve potential allergy risks, and phenoxyethanol, a preservative suspected to be reprotoxic.
There are also four ingredients or ingredient families that were classified as moderate risk found in 181 products. They are: EDTA, commonly used in foaming products; laureth and lauryl sulfate, which are foaming agents; mineral oils, byproducts of petroleum, which could be contaminated by impurities, and nanoparticles.