Yet regulators remain torn.
The FDA has banned flavored e-cigarettes that appeal to kids. But new research shows that the danger of flavors could go beyond their appeal to kids. The flavorings themselves could cause damage.
As vaping increases among youth, so do the life-threatening lung injuries that accompany it. 'Popcorn lung' is the latest.
Defining what this disease is and who has it has helped those investigating the outbreak understand what caused it.