Popcorn may cause lung disease:

A chemical used to give butter flavour to popcorn can damage the lungs and airways of mice, US government experts reported. Tests on mice show that diacetyl, a component of artificial butter flavouring, can cause a condition known as lymphocytic bronchiolitis, said the team at the National Institute of Environmental Health Sciences, part of the National Institutes of Health. The condition can lead to obliterative bronchiolitis-or "popcorn lung"- a rare and deblliting disease seen in workers at microwave popcorn packaging plants and at least one consumer.