Chemicals From Roasting Coffee Linked to Serious Lung Condition

According to a study conducted by journalists at the Milwaukee Journal-Sentinel, the people roasting coffee beans are exposing themselves to dangerous levels of diacetyl, a chemical used to add flavor and aroma to foods that may cause a condition known as obliterative bronchiolitis. The study picked up diacetyl quantities of more than four times the limit recommended by the Centers for Disease Control and Prevention (CDC).

More than 10 years ago, diacetyl came under fire in an investigation by the National Institute of Occupation Safety and Health after it was declared responsible for bronchiolitis obliterans, sometimes called “popcorn lung,” in microwave popcorn plant workers. Many popcorn plant workers contracted the disease and some died as a result. The diacetyl levels in the coffee roasters are comparable to those that affected the popcorn plant workers.

Studies Involving Diacetyl

While the U.S. Food and Drug Administration (FDA) classifies diacetyl as safe to ingest in small amounts, multiple studies have shown that it can be toxic when inhaled.

In August 2011, the National Institute of Occupational Safety and Health (NIOSH) released a draft rule recommending that no worker should be breathing air that is 5 parts per billion diacetyl over the course of a 40 hour work week, or levels above 25 parts per billion during any 15 minute time period.

In 2013, the CDC itself conducted two studies that showed strong evidence of people developing obliterative bronchiolitis after roasting coffee for only a few months. Diacetyl particles are small enough to bypass hairs and mucous in the nose and throat and get into the smallest airway passages, where they cause obliterative bronchiolitis, an irreparable lung condition. Symptoms of the disease that do not improve when away from work include dry cough, wheezing, and shortness of breath that worsens with exertion.