What it is
A flammable carcinogenic gas used to produce PEGs, laureth surfactants, and to sterilise medical devices.
What it does
Not an intentional cosmetic ingredient; appears as residual contamination in ethoxylated ingredients.
Why it’s a concern
Classified by IARC as Group 1 (carcinogenic to humans) with sufficient evidence for breast cancer and lymphohaematopoietic cancers. Measured alongside 1,4-dioxane in ethoxylated ingredient surveys. Avoid ethoxylated surfactants without manufacturer-confirmed residual testing.
Also known as
oxiraneEO
CAS numbers
75-21-8
Commonly found in
residual in PEGs, laureth surfactantssterilised medical devices
Safer alternatives
- non-ethoxylated alternatives (glucosides)
Related chemical families
Sources
- IARC Monograph Volume 100F