Popcorn Workers Lung (I) - is it just butter flavoring?)

Popcorn packers lung (PPL) illustrates the strength and some weaknesses of the current incarnation of NIOSH. [This post got out of hand with searching for background, and will tail off at the end. The Dodger will use the "least postable unit" approach to fill up a whole week's traffic.]

The strength of NIOSH is ability to respond to reports with combined occupational medicine, epidemiology, industrial hygiene [exposure characterization] and toxicology resources. The weakness is how long it takes.

The main point here is what should practitioners do to respond to clusters of occupational respiratory disease when they first emerge? The story parallels outbreaks of hypersensitivity pneumonitis in metal machining plants, lifeguard lung, legionaires disease, and even the post office anthrax experience.

Recently, victims at the index plant won judgements against International Flavors and Fragrances, for 10's of millions of dollars for devastating lung disease. Accounts of litigation can be found at http://www.butterflavoringlunginjury.com/

BrooklynDodger started this post noting the JOEH paper on characterization of exposure in the most recent issue, late 2005. The Dodger thought, how long has this been going on, and how long has the OH community been ignorant of the exposure levels? For interest, NIOSH reported
"Diacetyl, the predominant ketone in the plant, was present in
concentrations ranging from below detectable limits to 98 parts per million
parts air by volume (ppm), with a mean of 8.1 ppm (standard deviation 18.5 ppm).
The average ketone concentrations were highest in the microwave mixing room
where the 10 area samples had a mean diacetyl concentration of 37.8 ppm (SD 27.6
ppm)"

[The Dodger faults the authors for reporting, and the reviewers and editors for permitting them to report, arithmetic mean values rather than medians [easy to do], geometric means, or a mean value back calculated from the geometric mean and observed variance. The mean is less stable and suggests a higher exposure level over the population, thereby suggesting a lower unit risk.]

However, these data were reported in the NEJM paper in 2002.

An MMWR report appeared in April 2002, not much in advance of NEJM. The MMWR did report the geometric mean, which was reported as "The geometric mean air concentration of diacetyl was 18 parts per million parts air (ppm) in the room where the mixing tank was located, 1.3 ppm in the microwave-packaging area, and 0.02 ppm in other areas of the plant." [For epidemiologists, the Dodger notes that the geometric mean was 1/2 the arithmetic mean.]

http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5116a2.htm

Thus, the JOEH publication is an echo of previous information, either a product of "least publishable unit" publication or a slow editorial process at the journal.

[to be continued]

BrooklynDodger sympathizes with the team, especially the IH folks. Here's a devastating outbreak of disease. The most prominent chemical exposure is a food additive. Probably there's no toxicity data for this chemical, if there is it's probably feeding. [BrooklynDodger is going to work on this in the tox post]. It probably isn't that irritating and it does smell good. 100 ppm is a lot of organic vapor these days, but IH's think of 100 ppm as a TLV for a not specially toxic solvent.


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J Occup Environ Hyg. 2005 Mar;2(3):169-78.

Characterization of respiratory exposures at a microwave popcorn plant with cases of bronchiolitis obliterans.

Kullman G, Boylstein R, Jones W, Piacitelli C, Pendergrass S, Kreiss K.

National Institute for Occupational Safety and Health (NIOSH), Morgantown, West Virginia 26505, USA. gjk1@cdc.gov

Eight former workers from a microwave popcorn packaging plant were reported to have severe obstructive lung disease consistent with bronchiolitis obliterans. Investigations into respiratory exposures at this plant were done during August through November of 2000. ... Workers in the microwave production areas of the plant were exposed to particulates and a range of organic vapors from flavorings. The particles were comprised largely of salt and oil/grease particles. Respirable dust concentrations (area plus personal) in the microwave mixer job category, the highest job exposure category in the plant, ranged from 0.13 milligrams per cubic meter of air (mg/m3) to a high of 0.77 mg/m3. ...The predominant compounds identified in the microwave mixing room included the ketones diacetyl, methyl ethyl ketone, acetoin, and 2-nonanone, and acetic acid.

Diacetyl, the predominant ketone in the plant, was present in concentrations ranging from below detectable limits to 98 parts per million parts air by volume (ppm), with a mean of 8.1 ppm (standard deviation 18.5 ppm). The average ketone concentrations were highest in the microwave mixing room where the 10 area samples had a mean diacetyl concentration of 37.8 ppm (SD 27.6 ppm) and a mean acetoin concentration of 3.9 ppm (SD 4.3 ppm). These data show that workers involved in microwave popcorn packaging can be exposed to a complex mixture of VOCs from flavoring ingredients; animal studies show that diacetyl can cause airway epithelial injury, although the contributions of other specific compound(s) associated with obstructive respiratory disease in these workers is still unresolved.