A health-surveillance system put in place after the terrorist attacks of September 2001 has been used to pinpoint the cause of the vaping-related lung injuries that have killed 54 Americans and sent more than 2,500 people to the hospital.

Using this system, researchers at the Centers for Disease Control and Prevention have found that the lung injuries rose sharply in June of this year.

Dr. Anne Schuchat, the CDC's principal deputy director, says this sharp spike strongly points to a single culprit for most of these cases: vitamin E acetate, an additive found in illicit cannabis-containing vapes.