Members of the Democratic Women's Caucus are urging the FDA to address concerns about the safety and regulation of tampons after a study found heavy metals, including lead, in many popular products.

Minnesota Gov. Tim Walz signed a law last year requiring public schools to provide period products "to all menstruating students" in grades 4-12. Some Republicans are now criticizing him for it.

A first-of-its-kind study found lead, arsenic and other heavy metals in various tampon brands, but didn't link them to harmful health effects. Experts explain why it matters — and what to watch for.