The US Food and Drug Administration (FDA) will examine the potential risks posed by tampons after a study found toxic metals in products from more than a dozen popular brands.

The FDA said it will conduct a lab study mimicking the normal use of tampons to see how much – if any – metals may be released into the human body. The agency will also review all research in the area to shed light on the potential health impact of these products.

“We want the public to know that before tampons can be legally sold in the US, they must meet FDA requirements for safety and effectiveness,” the FDA said in a statement quoted by CNN. “Manufacturers must test the product and its component materials before, during, and after manufacturing.”

The action follows a study published in July, which found arsenic and lead in organic and nonorganic tampons. The researchers carried out a blinded experiment of 30 tampons from 14 brands, purchased from major online retailers and stores in the US, the UK and Greece. 

The study detected an average of 100 nanograms per gram of lead and 2 nanograms per gram of arsenic in the tampons.

According to the FDA, the July study did not test whether metals are released from tampons when used. “It also did not test for metals being released, absorbed into the vaginal lining, and getting into the bloodstream during tampon use,” the agency said.

The FDA expects to find the answers to these questions in its examinations.