Chemical flavorings found in e-cigarettes linked to lung disease 'Diacetyl, a flavoring chemical linked to cases of severe respiratory disease, was found in more than 75 percent of flavored electronic cigarettes and refill liquids tested by researchers at Harvard T.H. Chan School of Public Health. Two other related, potentially harmful compounds were also found in many of the tested flavors, which included varieties with potential appeal to young people such as cotton candy, “Fruit Squirts,” and cupcake. The study was published online today in Environmental Health Perspectives. The Occupational Safety and Health Administration and the flavoring industry have warned workers about diacetyl because of the association between inhaling the chemical and the debilitating respiratory disease bronchiolitis obliterans, colloquially known as “popcorn lung” because it first appeared in workers who inhaled artificial butter flavor in microwave popcorn processing facilities.' (News.Harvard.edu, 9th December 2015.) If you use e-cigarettes, stop.