Abstract: Between January 2005 and March 2006, Employee #1 and Employee #2 became seriously ill with bronchiolitis obliterans while working for Carmi Flavors and Fragrances Co., Inc. located in Commerce, CA. Employees #1 and #2 were compounders at the employer's facility. The facility was a flavor manufacturer where both liquid and powder flavors were manufactured. Employee 1 operated the large and small ribbon blenders. The small blender had a capacity of 50 pounds, and the large blender had a capacity of 1,000 pounds. Employee #1 operated the large blender for the last two years and the small blender for six years before that. Both Employees #1 and #2 made flavors by using recipes in which several raw ingredients were mixed together to make a particular flavor. The flavors included butter flavoring using the compound diacetyl. Both employees developed symptoms including shortness of breath, coughing, and spitting up mucous. After seeing a number of doctors, Employee #1 was diagnosed by a lung specialist in April, 2006 with brochiolitis obliterans attributed to diacetyl exposure. Employee #2 also saw a number of doctors before being diagnosed in August 2006 with bronchiolitis obliterans due to diacetyl exposure. Employees #1 and #2 were not trained on the hazards of the chemicals they were using. The room in which both employees worked did not have adequate ventilation. Employee #1 used a half mask respirator, and Employee #2 used a dust mask while working, but neither was trained on the use of a respirator, and the employer did not have a respiratory protection program in place. Both employees were hospitalized for treatment.