At salons everywhere, women swear by the "Brazilian keratins" - treatments that deliver a drop-dead gorgeous "do," CBS News correspondent Michelle Miller reports.
Mary Ann Dodge, a client at Ziba Salon, said she did it "because with this humid weather, I turned into a Chia pet."
The smooth, straight, celebrity look costs a few hundred but lasts for months.
But some of the hair-smoothing products contain formaldehyde - a chemical the Environmental Protection Agency considers a carcinogen. This week, the Occupational Safety and Health Administration, or OSHA, recommended stylists stop using products with formaldehyde, which goes by a number of different names.
Stylist George Allen Patricio offers a gas mask to clients worried about the fumes.
Patricio said he doesn't have a problem using the products knowing they have formaldehyde.
"Well, if they say they're formaldehyde-free, and I believe them," Patricio said.
But regulators found the toxin even in some products labeled formaldehyde-free.
The Trio Salon in Chicago is now switching brands. OSHA's been in twice to measure formaldehyde levels in the store's air.
"Most of these treatments contain a small amount of formaldehyde, and it's important that OSHA finds it safe," said Trio Salon owner Alex Ioannou.
It's the second warning this week to women about the price of so-called perfect hair. A study by the Cleveland Clinic found that hair weaves that are too tight are a culprit in causing baldness and scarring in nearly 30 percent of African-American women.
Dr. Jeanine Downie, a dermatologist, said when patients come to her with balding and scarring, she hands over a box of tissues and talks to them about different wigs they can get.
"It's done," Downie said.
In the documentary "Good Hair," comedian Chris Rock put the $8 billion black beauty-care business under the microscope, watching chemicals used in hair products dissolve metal.
Maybe the hottest new trend in hair care will be one that comes warning free.
Professional smoothing treatment brand Brazilian Blowout wrote CBS News the following response on their product:
Thank you for your time today and for your understanding that Brazilian Blowout is a brand and not a category.
We are currently attempting to contact Federal OSHA as we have never been contacted by them regarding their research of Brazilian Blowout. To date all state OSHA testing that has been made available to us clearly demonstrates that our product is safely below all OSHA defined air monitoring levels.
In the meantime, Brazilian Blowout has launched "Brazilian Blowout ZERO" for anyone concerned about the hair smoothing category. ZERO utilizes a new plant derived system that delivers exceptional results without any controversial ingredients.