In 2000, NIOSH conducted an investigation of exposures at a microwave popcorn manufacturing plant in Missouri. Public health officials contacted NIOSH because a cluster of former employees of the facility had developed a rare lung disease called bronchiolitis obliterans. The majority of employees diagnosed with bronchiolitis obliterans had been exposed to mixtures of butter flavoring chemicals. Evaluations of employees working in the plant revealed high rates of both respiratory symptoms and abnormal lung function.1 The investigation concluded that there was "a risk for occupational lung disease in workers with inhalation exposure to butter flavoring chemicals".2
Investigations of other workplaces have also shown that employees that use or manufacture certain flavorings have developed similar health problems. Because many of the cases have been associated with popcorn manufacturing plants, the term "popcorn lung" has often been used to describe the respiratory symptoms and fixed obstructive lung disease seen in these employees. Although much of the research and attention has been focused on butter flavorings, employees who are involved in the use or manufacture of other types of flavorings may also be at risk.2
Flavorings can be either natural or manmade. Some are simple and made up of only one ingredient but others are complex mixtures of several substances. Employees may be exposed to flavorings in the form of vapors, dusts, or sprays.2 There are many different types of flavorings and most have not been tested for respiratory toxicity. The Food and Drug Administration (FDA) regulates food additives for safety when eaten, but it does not require testing by other routes of occupational exposure, such as inhalation. Research continues to determine if certain components or combinations of flavorings are associated with pulmonary disease. Consumers are not believed to be at risk from preparing or eating microwave popcorn products.3
There are currently no specific standards for occupational exposure to butter-flavoring or the chemical diacetyl. However, OSHA standards regulating all workplaces offer protection to workers exposed to these substances.
1 Kreiss K. et al. "Clinical bronchiolitis obliterans in workers at a microwave-popcorn plant". New England Journal of Medicine 347.5(2002): 330-330.
2 Gilster-Mary Lee Corporation, Jasper, Missouri National Institute for Occupational Safety and Health (NIOSH) Health Hazard Evaluation Report (PDF). HETA 2000-0401-299, (2006, January).
3 Limiting Job Exposures to Food Flavorings, Flavoring Ingredients, is Recommended in New Alert. US Department of Health and Human Services (DHHS), National Institute for Occupational Safety and Health (NIOSH) Update, (2004, January 15).
Workers have a right to a safe workplace. The law requires employers to provide their employees with working conditions that are free of known dangers. The OSHA law also prohibits employers from retaliating against employees for exercising their rights under the law (including the right to raise a health and safety concern or report an injury). For more information see www.whistleblowers.gov or worker rights.
OSHA can help answer questions or concerns from employers and workers. To reach your regional or area OSHA office, go to OSHA's Regional & Area Offices webpage or call 1-800-321-OSHA (6742).
Small business employers may contact OSHA's free and confidential on-site consultation service to help determine whether there are hazards at their worksites and work with OSHA on correcting any identified hazards. On-site consultation services are separate from enforcement activities and do not result in penalties or citations. To contact OSHA's free consultation service, go to OSHA's On-site Consultation webpage or call 1-800-321-OSHA (6742) and press number 4.
Workers may file a complaint to have OSHA inspect their workplace if they believe that their employer is not following OSHA standards or that there are serious hazards. Employees can file a complaint with OSHA by calling 1-800-321-OSHA (6742), online via eCompliant Form, or by printing the complaint form and mailing or faxing it to your local OSHA area office. Complaints that are signed by an employee are more likely to result in an inspection.
If you think your job is unsafe or you have questions, contact OSHA at 1-800-321-OSHA (6742). It's confidential. We can help. For other valuable worker protection information, such as Workers' Rights, Employer Responsibilities, and other services OSHA offers, visit OSHA's Workers' page.
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