There have been so many reports out there that link dangers of nail polish ingredients with salon infections, but now Butter London, as well as other brands are selling ” 3 free polishes” that are gorgeous colors that are free of formaldehyde, DP, and toluene, which are horrible toxic ingredients. These ingredients have been linked with cancers, as well as health ailments. High levels of these toxins can also have harmful effects on the respiratory and nervous systems. If I know I’m going to get my nails done, I’ll take my own polish for them to use. If you are unable to get those type of polishes, make sure you go to a well ventilated place that have open windows and doors , so your not breathing in those chemicals.