A Missouri man is the eighth person to die in the United States of an illness linked to vaping.

More than 500 people have suffered lung injuries and illness in the U.S. linked to vaping.

There’s been at least one serious illness in Canada.

While experts at the U.S. Centers for Disease Control know that more than half of the victims are under 25 years old, they don’t know what’s causing the problem, so an investigation has been launched to figure this out.

In the meantime, CDC Principal Deputy Director Dr. Anne Schuchet has some advice.

She says anyone who uses an e-cigarette or vaping product should not use or buy these products off the street, and should not modify or add any substances to the products.