A study published in 2015 in the journal Environmental Health Perspectives showed that harmful chemicals associated with “popcorn lung” are present in many types of flavored e-cigarettes, particularly those with flavors like fruit and candy that may appeal to young smokers. Of the 51 flavored e-cigarettes tested, flavoring chemicals were found in 47 and diacetyl specifically in 39 samples. This suggests a potentially dangerous level of exposure via e-cigarettes to chemicals that can cause severe lung damage.