The popular accessories can include flame retardants, phthalates, and other substances linked with cancer and other dangers.
The mother of 'Today' host Savannah Guthrie has been missing since January 31.
A Silent Spring Institute study identified 48 chemicals of public health concern in hair extension, including 12 flagged under California's Proposition 65 as likely to cause cancer or reproductive harm.
A person who was detained for questioning in the investigation into Nancy Guthrie’s disappearance has been released. The man was brought in for questioning on Tuesday in connection with the alleged kidnapping of the 84-year-old mother of NBC News anchor Sav...