Study Finds Chemical in E-Cigarettes and Refill Liquids Linked to “Popcorn Lung” Disease

Researchers at Harvard T.H. Chan School of Public Health said a flavoring chemical linked to a dangerous respiratory disease was found in more than 75% of flavored electronic cigarettes and refill liquids. Diacetyl is associated with a debilitating respiratory disease called bronchiolitis obliterans (BO), also known as “popcorn lung” because it first appeared in workers who inhaled artificial butter flavor in microwave popcorn processing facilities.

The study, which was published online Wednesday in Environmental Health Perspectives, also found two other potentially harmful compounds in many of the tested flavors, including cotton candy, “Fruit Squirts,” and cupcake.

“Recognition of the hazards associated with inhaling flavoring chemicals started with ‘popcorn lung’ over a decade ago. However, diacetyl and other related flavoring chemicals are used in many other flavors beyond butter-flavored popcorn, including fruit flavors, alcohol flavors, and, we learned in our study, candy-flavored e-cigarettes,” said lead author Joseph Allen, assistant professor of exposure assessment sciences.

According to the research, at least 1 of the 3 chemicals was detected in 47 of the 51 flavors tested. In 39, diacetyl was detected above the laboratory limit of detection, while acetoin and 2,3-pentanedione were detected in 46 and 23 and of the flavors, respectively.

In 2004, The U.S. Centers for Disease Control and Prevention (CDC) reported multiple cases of popcorn disease in workers in a microwave popcorn plant in Missouri in 2000. It is a serious and irreversible disease in which the tiny air sacs in the lungs become scarred. After investigation by the NIOSH (National Institute of Occupation Safety and Health), it was discovered that a flavoring agent, diacetyl, was used to give the popcorn a buttery taste, and that inhalation of this flavoring likely contributed to the development of the illness.

The disease that results often is associated with cough and shortness of breath, similar to that seen in people with chronic obstructive pulmonary disease (COPD). This process is irreversible by current therapy.

“Since most of the health concerns about e-cigarettes have focused on nicotine, there is still much we do not know about e-cigarettes. In addition to containing varying levels of the addictive substance nicotine, they also contain other cancer-causing chemicals, such as formaldehyde, and as our study shows, flavoring chemicals that can cause lung damage,” said study co-author David Christiani, Elkan Blout Professor of Environmental Genetics.