OPI PLAY THE PEONIES. I didn't know this: "Since 2006, OPI has reformulated its entire line to eliminate DBP (dibutyl phthalate) and Toluene. Formaldehyde has never been an ingredient in OPI Nail Lacquers. Some OPI Nail Strengtheners / Hardeners do contain formaldehyde, while others are formulated without it to give consumers a choice."
OPI Nail Treatments NTT60 Natural Nail Strengthener Base Coat