A number of microwave popcorn manufacturers are making efforts to remove the chemical food additive diacetyl from their products. Diacetyl, which is found in butter flavoring mixtures used in microwave popcorn, may cause bronchiolitis obliterans, a lung disease. The New York Times reports that "the three companies that sell Orville Redenbacher, Act II, Pop Secret and Jolly Time microwave popcorn said they planned to change the recipes for their butter-flavored microwave popcorn to remove diacetyl." For a number of years, workers at microwave popcorn manufacturing plants have been at known risk of developing lung disease (called "popcorn lung") due to on-the-job exposure to diacetyl. Now, ABC News is reporting the first known case of "popcorn lung" in a consumer who ate large quantities of microwave popcorn. The U.S. Food and Drug Administration (FDA) is investigating the link between the food additive diacetyl and development of lung disease.