What it is
The simplest aldehyde, a colourless pungent gas typically used in 37% aqueous solution (formalin).
What it does
Direct preservative in some nail hardeners, hair-smoothing treatments, and industrial applications.
Why it’s a concern
Classified by IARC as Group 1, causally associated with nasopharyngeal cancer and myeloid leukaemia. OSHA regulates workplace exposure. Brazilian keratin hair treatments have been tested to release formaldehyde well above safe limits during blow-dry steps. Banned or strictly restricted in cosmetics in the EU.
Also known as
methanalmethylene oxide
CAS numbers
50-00-0
Commonly found in
nail hardenerkeratin hair smoothingembalming fluid
Safer alternatives
- formaldehyde-free keratin treatments
- salon ventilation and PPE if used
Related chemical families
Sources
- IARC Monograph Volume 100F
- OSHA Formaldehyde Standard 29 CFR 1910.1048