But the California health department reports that only 475 manufacturers are included on the site after five years of data collection, and many list ingredients as "trade secrets."

"You had the option to check 'trade secret' and then you didn't have to fill out all the information," said Ann Latendresse, a spokeswoman for Great Clips, a hair salon chain that sells its own brand of hair products. "It was just easier. It was just a box you could check." After being contacted by a news reporter, Great Clips said it would begin correcting its entries in the database, disclosing its "trade secrets."