By David Michaels
The outbreak of severe lung disease caused by exposure to diacetyl, the chemical that makes food taste like artificial butter flavor, is growing. According to the California Department of Health Services, there are now eight known cases of severe obstructive lung disease among workers exposed to diacetyl, with three more reported cases under investigation.
How many cases are occurring in other states? No one knows, because California is the only state in the country that is actively collecting information. Whatâs striking about the California cases is that none of the workers are employed in microwave popcorn plants, the factories where the first cases of diacetyl-caused lung disease were identified. (The identification of the first cases of bronchiolitis obliterans at these factories is the reason the disease was given the now out-dated label âpopcorn workersâ lung.â)
The food industry is a national one â food factories around the country use the same chemicals that are making workers sick in California. It has been almost six months since a group of unions and scientists petitioned OSHA for an emergency rule to protect workers from diacetyl.
OSHA has yet to take any action in response (this remains a case study in regulatory failure). The states, especially those with their own OSHA plans, can act on their own. Perhaps state epidemiologists in the other 49 will read the description of the known cases in California, compiled by Barbara Materna, PhD, CIH, Chief, Occupational Health Branch, California Department of Health Services, and begin to gather comparable information that could lead to state action to protect food indsutry workers. Here’s a portion of the California report:
These eight workers are 29 to 49 years old. They all live in Southern California, where the majority of flavor manufacturing plants are located. Six are male, and two are female. All are Latino, and half are known to prefer to be interviewed in Spanish. Of the six for which smoking history is known, none have ever been smokers. Only one worker is known to have had asthma as a child; the majority did not have asthma or other breathing problems before working in this industry.
The workers were or are currently employed at five different flavor manufacturing companies in Southern California. Seven workers for whom a job history is available have all worked in jobs that involve mixing chemicals, including diacetyl, to make food flavorings (flavor compounding). Some of the workers only made powder flavorings, while others made both liquid and powder flavorings. Of the eight workers, only one is still working at the same company, but has been moved to a job that does not involve diacetyl exposure.The time reported between beginning work in flavoring manufacture and first experiencing symptoms such as cough, wheezing, or shortness of breath varies between one month and several years for these workers (this information is available on six workers). Some of the workers were initially treated for asthma, bronchitis, or allergic rhinitis; however, their conditions continued to deteriorate. Early on in some of these cases, an association with workplace exposure does not seem to have been considered.
Spirometry testing results (available for seven of the workers) show a Forced Expiratory Volume in one second (FEV1) ranging from 18 to 44% of what is normally predicted based on age, race, gender, height, and weight. FEV1 shows the volume of air that can be forced out of the lungs on exhalation in one second. A reduced FEV1 is one indicator of obstruction in the lung that makes it more difficult to exhale. Further testing is indicated to determine the likely cause of the abnormality.
Most of these workers are severely impaired, cannot work, and suffer extreme shortness of breath on exertion (for example, they can only walk a very short distance). At least one is reported to be on a list for lung transplantation.
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.
Here’s some observations which might give the popcorn lung issue greater reach.
1. At the state level, they need to be occupational disease reporting laws such as there is in Michigan and could be elsewhere. This is a public health code modification which doesn’t run into the issue of legislating OSHA separately. The occupational disease law in Michigan produced critical information about the relationship of metalworking fluids and occupational asthma.
2. Occupational health practitioners should be aware of the background or population rate of disabling respiratory illness. Two (count them 2) workers out from work for a week from a respiratory diagnosis is unusual and should be considered a sentinel event. People used to ridicule this, saying what about the flu? Now we might say the opposite, what about the flu?
Three. Is there spectrum of occupational illness from diacetyl (and other causes of interstitial lung disease)? Do these facilities have substantial other workers with symptoms but not at the pathological result?
4. One of the diacetyl levels in commercial popcorn popping in and in consumer use of popcorn?
5. For those who are interested in structure activity relationships, remember Beta Gamma diketones. You can imagine they have the potential to cross-link proteins.
Please excuse some of the typos above. I’m learning dictation software.
Your comments are most welcome. Several states, I believe, have laws requiring reporting of occupational illnesses. They are pretty much unknown and rarely if ever even discussed among physicians. The bigger issue is that of diagnosis. Given the number of cases among food industry workers in the LA area, it seems likely that similar cases are occurring elsewhere, but are not being identified as occupational in origin.
Diacetyl exposure among people who pop popcorn, at home or commercially? A great question. There is no published research on the exposure of consumers to the heated vapors of diacetyl and other chemicals released when microwave popcorn is popped. The EPA has still not released the study it conducted looking at the emissions from microwave pop corn after its been microwaved. Here’s the background:
In the middle of 2003, the Environmental Protection Agency (EPA) announced that a study on the chemicals released in the popping and opening of packages of microwave popcorn was underway and was expected to be completed by the end of that year. The EPA has yet to disclose the results of that study.
In July 2006, in response to my inquiry about the status of the study, the Chief of the EPAâs Indoor Environment Management Branch provided the following response:
âThe principle investigator on this project was transferred to homeland security duties, there the final report has been delayed. It is anticipated that the report will be sent as a manuscript for publication in a peer reviewed journal in October, once internal and industry reviews are completed. When it is published will be up to the journal.â
On July 26, 2006, on behalf of the SKAPP Planning Committee, I wrote to EPA Administrator Stephen L. Johnson, asking for expedited release of the study and objecting to the preferential treatment given to industry. The EPA responded that the paper summarizing their findings has undergone internal and external review and will be sent to industry âsolely to ensure that no confidential business information is releasedâ; the agency plans to submit the paper to a scientific journal this fall and anticipates publication by mid-2007.
This fall has come and gone, but no news yet from EPA.