A study published in 2015 in the Journal Environmental Health Perspectives showed that harmful chemicals associated with popcorn lung, or bronchiolitis obliterans, are found in many types of flavored e-cigarettes, particularly those with flavors like fruit and candy, which may appeal to young smokers.

What causes popcorn lung?

In 2004, The US Centers for Disease Control and Prevention (CDC) reported several cases of bronchiolitis obliterans in workers in a microwave popcorn plant in Missouri in 2000. After investigation by the NIOSH (National Institute of Occupation Safety and Health), it was discovered that a flavoring agent termed diacetyl (2,3-butanedione) was used to give the popcorn a buttery taste. Inhaling this chemical flavoring likely contributed to the development of this lung disease.

Popcorn lung (bronchiolitis obliterans) often is associated with symptoms of cough and shortness of breath, similar to that seen in people with chronic obstructive pulmonary disease (COPD). This process is irreversible with currently available therapy.

More recently, a legal case was settled in Colorado for over 7 million dollars. The award was granted to a consumer who developed bronchiolitis obliterans ("popcorn lung") after eating two bags of microwaved popcorn every day for 10 years. Since workers who manufacture microwaved popcorn were at risk, the judgment stated that the popcorn manufacturers and the supermarket corporations should have realized that consumers could also be at risk of this lung disease.

Another chemical similar to diacetyl called 2,3-pentanedione also is suspected as a cause of the disease. Both diacetyl and 2,3-pentanedione are released into the air during grinding and packaging of coffee beans. These two chemicals are members of the chemical class alpha-diketones. Other members of this chemical class may cause similar lung damage according to the CDC, but they have not yet been studied.

Other causes of popcorn lung may be due to some of the following chemicals when inhaled.