ALBANY, N.Y. - Fourteen attorneys general, including Kathleen G. Kane of Pennsylvania, have asked Congress to launch an investigation of the herbal supplements industry and consider giving the U.S. Food and Drug Administration stronger oversight of the industry, New York Attorney General Eric Schneiderman announced Thursday.

"When consumers take an herbal supplement, they should be able to do so with full knowledge of what is in that product and confidence that every precaution was taken to ensure its authenticity and purity," Schneiderman said.

Under federal law, herbal supplements, vitamins, and other dietary supplements are subject to far less rigorous oversight than pharmaceutical products.

No regulation requires a firm to disclose to the FDA or consumers information about the safety or purported benefits of dietary supplements, according to the agency's website. The manufacturer is responsible for ensuring that the ingredient list is accurate.

The FDA can take action against supplements only if they are proven to be unsafe.

Schneiderman alleged in February that DNA tests on certain store-brand supplements found none of the herbs listed on the labels. Industry groups and some consumer advocates have criticized Schneiderman's testing method.

GNC, one of the retailers targeted by Schneiderman, said last week that it had provided him with test results from independent labs showing its products were safe and properly labeled, and had agreed to add DNA testing to its quality-control procedures.

Daniel Fabricant, former director of the FDA's dietary supplement division and now executive director of the Natural Products Association trade group, called the attorney generals' action "harassment based on science fiction."