Toluene is the nail polish ingredient used to create a smooth application and finish. However, its fumes are highly toxic.
Studies have shown that exposure to toluene can cause neurological damage, decreased brain function, impaired breathing, hearing loss, and nausea.
When inhaled too frequently by pregnant women, it may result in impaired fetal development.
Animal studies have also shown that toluene is linked to reproductive impairment, immune system toxicity, and blood cancers like malignant lymphoma.
European Union has restricted the use of toluene in personal care products, including nail polish, and advises that pregnant women and children should not be exposed to its fumes.