NIH -- A new study shows that exposure to a chemical called diacetyl, a component of artificial butter flavoring, can be harmful to the nose and airways of mice. Scientists at the National Institute of Environmental Health Sciences (NIEHS), part of the National Institutes of Health, conducted the study because diacetyl has been implicated in causing obliterative bronchiolitis (OB) in humans. OB is a debilitating but rare lung disease, which has been detected recently in workers who inhale significant concentrations of the flavoring in microwave popcorn packaging plants.
