1. Formaldehyde: Chemical produced on a large scale worldwide and used by multiple industries as a conservative and disinfectant. It has been classified as carcinogenic by experts from the World Health Organization.
2. Toluene: It can cause nausea, memory problems, fatigue and confusion as it acts on the nervous system. Skin contact causes irritation and dermatitis.
3. Dibutyl Phthalate: The use of this substance in cosmetics, including nail polish, is prohibited in the European Union, because of its toxicity.
4. Formaldehyde Resins: Derived from formaldehyde can cause irritation and dermatitis.
5. Camphor: The Food and Drug Administration (FDA) does not allow doses over 11%. In large quantities it is poisonous. If ingested can cause seizures, confusion, irritability and muscle neuro-hyperactivity.