Eight Months Later, Will FDA Finally Consider Diacetyl's Safety?

By David Michaels

Congresswoman Rosa L. DeLauro (D-CT), chair of the House of Representatives Appropriations subcommittee that funds the FDA has called on Food and Drug Administration to ban diacetyl until more research is completed. As we've written (here and here, for example), diacetyl is the artificial butter flavor chemical that has been crippling workers employed in flavoring, popcorn and snack food factories around the country.

In announcing her letter to FDA Commissioner Andrew von Eschenbach, Congresswoman DeLauro said:

In light of overwhelming scientific evidence, the possibility of harm to people who regularly prepare popcorn products containing diacetyl in a microwave oven can no longer be disregarded. For this reason, I am urging the FDA to consider revoking the generally safe designation for diacetyl and removing it from the market until further testing is completed. This chemical poses a real threat to the workers exposed to it. The FDA needs to take action on this issue and employ its regulatory mandate to protect the public.â

Here at the Project on Scientific Knowledge and Public Policy (SKAPP), we attempted to alert the FDA to the problem eight months ago. In September 2006, we petitioned the FDA to remove diacetyl from the âGenerally Regarded As Safeâ (GRAS) list, pointing out that âthere is compelling evidence that breathing diacetyl vapors causes lung disease and there is no evidence of a safe exposure level.â In March 2007, the FDA wrote us back, essentially blowing us off.

Now, one of the members of congress who controls the agencyâs funding has weighed in. I think we'll see the FDA finally focus on diacetyl.

Hereâs the text of her letter:

May 7, 2007

Andrew C. von Eschenbach, MD
U.S. Food and Drug Administration
5630 Fishers Lane
Rockville, MD 20852

Dear Commissioner,

I write to urge to you re-examine the designation âgenerally regarded as safeâ (GRAS) for diacetyl â the food flavoring chemical more commonly used in popcorn, but also found in pastries, frozen foods and candies.

When FDA codified diacetyl as GRAS in 1983, the Select Committee of GRAS Substances (SCOGS) concluded: âThere is no evidence in the available information on diacetyl or starter distillate that demonstrates or suggests reasonable grounds to suspect a hazard to the public when they are used at levels that are now current or that might reasonably be expected in the future.â However, I believe that recent developments call into question such findings.

Seven years ago this month, the Missouri Department of Health and Senior Services was contacted by physician to report eight cases of fixed obstructive lung diseases, bronchiolitis obliterans, also known as "popcorn lung,â in workers in a Missouri microwave popcorn plant. Follow-up investigations by the National Institute for Occupational Safety and Health (NIOSH) found diacetyl to have caused the lung disease. Since that time, cases of bronchiolitis obliterans have been identified in microwave-popcorn workers in several states, including Missouri, Iowa, Ohio, New Jersey, and Illinois.

In all, NIOSH has conducted six investigations at 10 microwave popcorn facilities, finding respiratory impairment among workers at a majority of the plants. However, it has become clear that the disease has struck workers in other segments of the food and flavoring industry, and is not limited to popcorn facilities. The disease in flavor-manufacturing workers has been identified in Ohio, California, Maryland, and New Jersey where diacetyl is used.

It is my understanding that many of these workers were made so ill that they are currently awaiting lung transplants. Scientists have called the effect of diacetyl on workersâ lungs "astonishingly grotesque" and likened it to âinhaling acid.â Three workers have died so far.

Five years ago last month, CDC, in its Morbidity and Mortality Weekly Report (MMWR), called for health care providers to report additional suspected cases of respiratory disease in workers exposed to food flavoring chemicals.

Last month, in MMWR, CDC recommended that employers implement safety measures to minimize worker exposure to flavoring chemicals, such as diacetyl.

Furthermore, the role of diacetyl in the causing harm to airway epithelium was suggested in studies of laboratory animals. NIOSH scientists have conducted several studies in which rats and guinea pigs exposed to diacetyl suffered adverse effects to their respiratory tissue and structure.

According to the New York Times, evidence suggesting the possibility of a link between diacetyl and lung disease was raised as long ago as 1993 in a study by a German company. The New York Times also reported that an industry trade association was made aware of the possible risk in 1996.

Certainly, in light of all this evidence, the possibility of harm to persons who regularly prepare popcorn products containing diacetyl in a microwave oven cannot be disregarded.

For all these reasons, I would urge you to re-consider that designation of diacetyl as generally safe with a view to its removal until further testing is completed. There seems to be compelling scientific evidence that this chemical poses a real threat to the workers exposed to it. It is critical that the FDA take action on this issue and employ its regulatory mandate to protect the public.

Thank you for your consideration of this request. I look forward to your response.


House Appropriations Subcommittee on Agriculture
Rural Development, Food and Drug Administration,
and Related Agencies

Thank you, Congresswoman DeLauro.

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.

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