A small manufacturing scene has grown up in Brooklyn around nail polish reformulated to exclude a lengthening list of controversial chemicals. These brands market themselves on what they leave out, appealing to salons and customers wary of ingredients.

The fictional label Ten Free, named for the number of chemicals it omits, blends and bottles its polish in a Sunset Park workshop and sells to studios across the city. Its founder says demand from salons drove the business as much as retail.

Chemists note that "free-from" marketing can overstate risks, and safety often depends on how products are used. Still, the brands have carved out a loyal following in a beauty market increasingly shaped by ingredient anxiety.