How safe is your weed? Patchy regulations may leave contaminants in the weed supply

Cannabis is legal in many states but not federally. As more Americans consume weed products, concern is growing about the risks of traces of contaminants such as pesticides and heavy metals.

Millions of Americans use cannabis and would like to think the products they buy are safe. But regulation is state by state and full of holes. NPR's new series digs into the risks and solutions.

(Image credit: Cecilia Sanchez)