New York Times, "Popcorn Butter Flavoring-Factory Illnesses Raise Inquiries"

          The workers, by and large, have been young and healthy. None were smokers, and none had any history of lung disease. But after working at plants that produce food flavorings, they all had one thing in common: they could not breathe. Over the last several years, California health officials have been tracking a handful of workers in flavoring factories who have been incapacitated with a rare, life-threatening lung condition — bronchiolitis obliterans — for which there is no cure or treatment.
          Usually found only in people who are poisoned by chemical fires or chemical warfare or in lung transplant patients, bronchiolitis obliterans renders its victims unable to exert even a little energy without becoming winded or faint. "The airways to the lung have been eaten up," said Barbara Materna, the chief of the occupational health branch in the California Department of Health Services. "They can’t work anymore, and they can’t walk a short distance without severe shortness of breath."
          Seven flavoring-factory workers in California are known to have the disease or similarly serious lung damage, and 22 others have had lung tests come back with abnormal results. In each case, scientists and health officials say, the common dominator is exposure to the vapors from a pungent yellow-colored flavoring called diacetyl, best known for giving microwave popcorn its buttery goodness. Officials from the Occupational Safety and Health Administration testified at a Congressional hearing last month on concerns about the additive. Several other federal agencies, including the National Institute for Occupational Safety and Health, the Food and Drug Administration and the Environmental Protection Agency, are also investigating the effects of diacetyl, the subject of scores of civil lawsuits filed on behalf of victims of so-called popcorn lung.

Learn more about butter flavoring lung injuries and "popcorn lung" lawsuits.