Dozens of workers around the country have developed the debilitating lung disease bronchiolitis obliterans, also known as “popcorn workers lung,” and other respiratory illnesses from exposure to vapors from diacetyl, a component of artificial butter flavor used in microwave popcorn and many other food products.
The National Institute for Occupational Safety and Health (NIOSH) conducted several studies that confirmed the link between occupational exposure to artificial butter flavoring and lung diseases. In 2000 they issued recommendations to a Missouri microwave popcorn plant about protecting workers from this hazard, and in 2003 they sent an alert recommending safeguards to 4,000 businesses that might use or make butter flavoring.