A new study by Silent Spring Institute shows that hair extensions contain more harmful chemicals than previously thought by experts.

The products tested contain toxic organotins, flame retardants, and other substances linked with cancer and other harmful health effects, according to the study.

"In our recent study, we evaluated 43 hair extension products from human hair, synthetic hair, and others, and what we found is a lot of chemicals in them," Dr. Elissia Franklin, a Houston doctor who worked on the study, said. "The chemicals that we found were known to cause cancer and reproductive harm. We know that a lot of folks have struggled with infertility and also birth defects."

As the industry grows, so do concerns about potential health impacts. Experts expect the global hair extensions market to surpass $14 billion by 2028.

"There have been folks that have said they're going to take their hair down and that's a personal decision. Again, it isn't about policing the individuals, but more so, holding the companies accountable," Franklin said.

As recently as last year, legislation co-sponsored by Houston Rep. Lizzie Fletcher aimed to place tighter regulations on cosmetic products.

The legislative package has not been signed into law.

ABC News Medical Correspondent Dr. Darien Sutton has advice for people who use hair extensions.

"So, looking at the label is really important here. Experts advise looking for labels like 'pretreated' or 'coated,'" Sutton said. "Sometimes that can increase your risk of chemical exposure, and then stepping down your level of exposure. You can do that by washing your extensions beforehand, and sometimes that can reduce your risk. Avoid heating without ventilation. That's really key here because inhaling these chemicals is also a part of it."

View this story in ABC13.