a group of California food-flavoring workers recently diagnosed with bronchiolitis obliterans, a rare and life-threatening form of fixed obstructive lung disease. Also known as popcorn workers lung, because it has turned up in workers at microwave-popcorn factories, the disease destroys the lungs. A transplant is the only cure.
Since 2001, academic studies have shown links between the disease and a chemical used in artificial butter flavor called diacetyl. Flavoring manufacturers have paid out more than $100 million as a result of lawsuits by people sick with popcorn workers lung over the past five years. One death from the disease has been confirmed.
"It's not some carcinogen where you get cancer 30 years from now or something. The people are dying right in front of you," said David Michaels of the department of environmental and occupational health at George Washington University. "You can't wait until you have all the evidence. You have to regulate it."
Even less is known about the health effects of eating diacetyl in butter-flavored popcorn, or breathing the fumes after the bag is microwaved.
http://www.washingtonpost.com/wp-dyn/content/article/2007/05/06/AR2007050601089.html?hpid=topnews