Abstract: Employee #1 had worked for Mission Flavors & Fragrances, Inc., a manufacturer of food flavorings and fragrances in Foothill Ranch, CA, since 2000. He mixed ingredients to create food flavorings. He was exposed to diacetyl while working in the production area, and his pulmonary function decreased steadily over the ten years. On July 21, 2010, he was diagnosed with chronic airflow obstruction disease as a result of his exposure to diacetyl while on the job. On November 10, 2010, he was diagnosed by a second doctor with bronchiolitis obliterans due to occupational exposure to diacetyl while working at Mission Flavors. The Division's Medical Unit became aware of the diagnosis of chronic airflow obstruction disease on July 26, 2010, by way of a letter from one of the doctors who made the diagnosis. The Division's medical unit has determined that there is sufficient evidence to support the diagnosis.