Consumers buying cosmetics and personal care products can look at the labels if they want to know what's in them. But the disclosure required by the U.S. Food and Drug Administration doesn't extend to professional-grade products used by hairdressers, manicurists and other beauty salon employees. Health advocates say this is a health risk for salon workers and their clients.

But beginning in July 2020, all beauty products sold in California will have to list their ingredients on their labels, thanks to legislation signed into law last week by Gov. Jerry Brown.

Meant to protect the state's roughly 300,000 licensed cosmetologists and 130,000 manicurists, the new law had the backing of entities including the Environmental Working Group (EWG). For instance, formaldehyde-based hair-straightening treatments pose a health risk to workers and clients because they emit toxic fumes while being applied, warned EWG in a 2011 report.

Get Breaking News Delivered to Your Inbox

Salon workers routinely handle personal care products with ingredients that are worrisome, often in workplaces with poor ventilation, according to EWG, which advocated for the law so salon workers could make informed choices.

Those choices involve their own health issues, as well as those of their customers, said one salon employee.

"I have a lot of clients with allergies, and you have to constantly ask them. So we need to know what's in everything," Elischa Fryman, a stylist at Bishops Cuts/Color told a CBS affiliate in Sacramento.