Diacetyl and 2,3-pentanedione exposures associated with cigarette smoking: implications for risk assessment of food and flavoring workers

Abstract

Diacetyl and 2,3-pentanedione inhalation have been suggested as causes of severe respiratory disease, including bronchiolitis obliterans, in food/flavoring manufacturing workers. Both compounds are present in many food items, tobacco, and other consumer products, but estimates of exposures associated with the use of these goods are scant. A study was conducted to characterize exposures to diacetyl and 2,3-pentanedione associated with cigarette smoking. The yields (μg/cigarette) of diacetyl and 2,3-pentanedione in mainstream (MS) cigarette smoke were evaluated for six tobacco products under three smoking regimens (ISO, Massachusetts Department of Public Health, and Health Canada Intense) using a standard smoking machine. Mean diacetyl concentrations in MS smoke ranged from 250 to 361 ppm for all tobacco products and smoking regimens, and mean cumulative exposures associated with 1 pack-year ranged from 1.1 to 1.9 ppm-years. Mean 2,3-pentanedione concentrations in MS smoke ranged from 32.2 to 50.1 ppm, and mean cumulative exposures associated with 1 pack-year ranged from 0.14 to 0.26 ppm-years. We found that diacetyl and 2,3-pentanedione exposures from cigarette smoking far exceed occupational exposures for most food/flavoring workers who smoke. This suggests that previous claims of a significant exposure–response relationship between diacetyl inhalation and respiratory disease in food/flavoring workers were confounded, because none of the investigations considered or quantified the non-occupational diacetyl exposure from cigarette smoke, yet all of the cohorts evaluated had considerable smoking histories. Further, because smoking has not been shown to be a risk factor for bronchiolitis obliterans, our findings are inconsistent with claims that diacetyl and/or 2,3-pentanedione exposure are risk factors for this disease.

Keywords:

• bronchiolitis obliterans
• 2,3-butanedione
• diacetyl
• food flavorings
• microwave popcorn
• 2,3-pentanedione
• National Institute for Occupational Safety and Health
• NIOSH

Acknowledgements

The authors would like to extend their appreciation to Ben Roberts of Cardno ChemRisk, and to Dr. Gene Gillman of Enthalpy Analytical, Inc., for their technical assistance with the preparation of the manuscript.

Declaration of interest

All the authors are employed by Cardno ChemRisk, a consulting firm that provides scientific advice to the government, corporations, law firms and various scientific/professional organizations. Cardno ChemRisk has been engaged by several manufacturers and suppliers of diacetyl and diacetyl- containing flavorings in various litigation matters. However, no external funding was received for the study, the research supporting the analysis, nor the time needed to prepare the article, and this paper was prepared and written exclusively by the authors, without review or comment by any clients including, but not limited to manufacturers and suppliers of diacetyl and diacetyl-containing products and their counsel. It is likely that this work will be relied upon in scientific and medical research and litigation. Two of the authors (Drs. Pierce and Finley) have served and may be called upon in the future to serve as expert witnesses in diacetyl litigation. The authors have not been engaged by the tobacco industry or been involved in any tobacco-related litigation.