By David Michaels

The National Institute for Occupational Safety and Health (NIOSH) has just released a study examining lung disease and exposure to flavor chemicals among workers at the Carmi Flavor and Fragrance Company factory in Commerce, California. One or possibly two cases of bronchiolitis obliterans had been known to public health authorities before the investigation. Of the thirty-four workers studied, three were found to have severe obstructive lung disease; NIOSH reports the expected prevalence of this condition in a group of relatively young workers is about one in a thousand.

A professional colleague close to the investigation provided The Pump Handle with this summary of the study and its implications:       

This study is the first detailed analysis of lung disease and exposure to diacetyl in a flavorings factory, and confirms what NIOSH found in their Hazard Evaluation in 1985. At Carmi, NIOSH followed up on a single case report from this company, did air measurements for diacetyl and other chemicals, and surveyed current and some former workers who made artificial butter flavors.

NIOSH found that, in addition to the “index case” with severe lung disease, two other workers had severe fixed airways obstruction. Of the three cases, two reported handling diacetyl in the production of powdered flavorings, and the third reported helping in the production of powdered butter flavorings when other workers poured diacetyl. According to the NIOSH report, all three workers with severe obstruction worked in the production room, an area where there have been less than 25 workers over the entire history of the plant. This is an alarming rate of lung problems; if this was found by NIOSH in just one small factory, other cases are certain to follow elsewhere.

When NIOSH measured the amount of dicaetyl in the workplace air, they found that the production room had the highest TWA diacetyl concentrations, ranging from below detectable limits (with an assigned a value of 0.002 ppm) to a high of 1.13 ppm. The mean concentration from the nine personal diacetyl samples from the powdered flavoring production area was 0.223 ppm, and the six area samples from this location had a similar mean of 0.249 ppm. Diacetyl concentrations from other plant areas were lower. The concentrations of diacetyl at this flavorings company were very similar to what NIOSH found in their studies of popcorn companies. Thus, this company was not some “bad actor,” and similar conditions can probably be found throughout the US and worldwide.

NIOSH is now confirming that diacetyl is a leading suspect in causing lung disease in these factories, but doesn’t rule out other exposures as well:

“Although it is highly likely that exposures to diacetyl contributed to the occurrence of severe fixed obstructive lung disease in production workers at the Carmi Flavors plant, whether or not the exposures to other flavoring chemicals also contributed to the development of disease in these workers is unknown.”

All other flavorings factories, and indeed all companies that use diacetyl or diacetyl-containing products, should immediately take steps to minimize and/or eliminate exposure to this dangerous chemical.

David Michaels heads the Project on Scientific Knowledge and Public Policy (SKAPP) and is Professor and Associate Chairman in the Department of Environmental and Occupational Health, the George Washington University School of Public Health and Health Services.