According to U.S. officials, a chemical that gives popcorn its butter flavor may damage the lungs and airways of mice. Researchers from the National Institute of Environmental Health Sciences said diacetyl, a component of artificial butter flavoring, may cause a condition known as lymphocytic bronchiolitis.

“This is one of the first studies to evaluate the respiratory toxicity of diacetyl at levels relevant to human health,” Daniel Morgan at NIEHS, whose team led the study, said in a statement.

Lymphocytic bronchiolitis can worsen over time and lead to obliterative bronchiolitis, also known as “popcorn lung.” This rare and debilitating disease has been seen in workers at microwave popcorn packaging plants, and at least one popcorn-eating consumer has been diagnosed with the condition.

ConAgra Foods Inc. and Weaver Popcorn Co Inc. recently said they will stop using diacetyl.

Source: Maggie Fox, Reuters, “Popcorn ingredient causes lung disease: U.S. study,” March 13, 2008. (http://www.reuters.com/article/idUSN1330524220080313?sp=true)