Information for Healthcare Providers

Advise Patients

Workers with flavoring-related lung disease should be 

removed from further exposure and relocated within 

the facility to areas where they will not be exposed to 

diacetyl or similar flavoring chemicals.

Remind patients of the importance of: 

•	 Using available exposure control methods such as 

ventilation hoods.

•	 Keeping flavoring containers tightly closed when not 

in use to prevent the contents from getting into the air. 

•	 Reading and understanding labels on containers and 

material safety data sheets for substances that they are 

exposed to in the workplace.

•	 Wearing personal protective equipment as appropriate.

Encourage patients to talk to their supervisors about:

•	 Training on hazard identification, procedures for safe 

handling of flavoring chemicals, and symptoms of 

flavoring-related lung disease. 

•	 Exposure control methods (e.g., ventilation, isolation) 

and work practices (e.g., standard procedures for 

cleaning the workplace and for handling and storing 

flavoring chemicals). 

•	 Wearing fit-tested respirators (protective breathing 

equipment) and other personal protective equipment 

(e.g., gloves, eye protection, aprons) to reduce exposures.

3. Report

Much remains to be learned about the nature of this serious 

lung disease. You can play an important role. With your 

assistance, the information gained from reporting can help 

identify high-risk work settings and guide efforts to prevent 

additional cases of flavoring-related lung disease.

DEPARTMENT OF HEALTH AND HUMAN SERVICES

Centers for Disease Control and Prevention

National Institute for Occupational Safety and Health

Reporting of Cases

Please report any cases of occupational lung 

disease with or without fixed airways obstruction 

that you suspect are attributable to flavoring 

chemicals to your State Health Department and 

the NIOSH Division of Respiratory Disease Studies 

(Telephone: 1–800–232–2114). 

Additional Information

To learn more about the effects of flavorings:

NIOSH Web site: 

www.cdc.gov/niosh/topics/flavorings

NIOSH [2003]. NIOSH Alert: Preventing Lung 

Disease in Workers Who Use or Make Flavorings

[http://www.cdc.gov/niosh/docs/2004-110].

NIOSH

Telephone: 1–800–CDC–INFO (1–800–232–4636)

TTY: 1–888–232–6348 | E-mail: cdcinfo@cdc.gov

or visit the NIOSH Web site at www.cdc.gov/niosh

For a monthly update on news at NIOSH, 

subscribe to NIOSH eNews by visiting 

www.cdc.gov/niosh/eNews

DHHS (NIOSH) Publication No. 2012–148

(supersedes 2012–107)

May 2012

Safer • Healthier • PeopleTM

In addition to exposure control methods, use a NIOSHcertified full-facepiece air-purifying respirator with at a 

minimum NIOSH-certified organic vapor cartridges and 

particulate cartridges/filters and other cartridges as necessary.

✓ Recognize ✓ Respond ✓ Report

Workers who breathe flavoring chemicals 

containing diacetyl, such as butter flavoring, 

may be at risk of severe obstructive 

lung disease.

Image courtesy of Jupiter Images

Flavoring-Related 

Lung Disease
What is the problem/illness? 

Severe obstructive lung disease has been identified in 

people who work with flavoring chemicals containing diacetyl, including butter flavoring. Animal studies suggest 

that some flavoring chemicals similar to diacetyl, such as 

2,3-pentanedione, may also be a hazard. Cases of severe 

lung disease have occurred in microwave popcorn plants 

and flavoring production plants. Lung biopsies in some 

affected people have shown the presence of a rare condition; constrictive bronchiolitis obliterans (also referred 

to as constrictive bronchiolitis, obliterative bronchiolitis, 

and bronchiolitis obliterans). In some workers, fixed airways obstruction has been severe enough to be fatal. 

Who is at risk? 

Workers who make, use, or work near flavoring chemicals 

containing diacetyl or 2,3-pentanedione may be at risk. 

Settings where these exposures may occur include:

•	 Flavoring plants 

•	 Microwave popcorn plants

•	 Commercial and retail bakeries

•	 Snack food and candy plants

•	 Dairy products and packaged vegetable oil plants 

(e.g., margarine, cooking oil)

•	 Other flavored food production plants

Exposures in the flavoring industry and in microwave 

popcorn production have caused workers to have severe 

lung disease. The burden of hazardous exposures and risk 

to workers in other settings remains unclear. However, it is 

important to consider the possibility of flavoring-related lung 

disease in workers who have been exposed to diacetyl or 

similar flavoring chemicals and have respiratory symptoms.

1. Recognize

Take an Occupational History

Take an occupational history to avoid missing exposures 

to flavorings. Affected workers may have used flavoring 

chemicals for a few months to a period of years. Ask your 

patients about jobs held, exposure to flavoring chemicals 

(and other dusts, mists, gases, vapors, or fumes), and if 

other coworkers have experienced similar symptoms. 

Sometimes workers are initially misdiagnosed with asthma, 

chronic bronchitis, emphysema, or pneumonia; or their 

symptoms are attributed to smoking.

2. Respond

Conduct a Medical Evaluation

Medical testing may include the following: 

•	 Spirometry most often shows an obstructive pattern 

of ventilatory impairment that does not improve after 

bronchodilators and sometimes shows a restrictive 

or mixed obstructive/restrictive pattern of ventilator 

impairment. Careful comparison of spirometry test 

results over time is important to identify potentially 

concerning declines in lung function. The rapid 

decline of lung function (even if it is still within the 

normal range) or the finding of a reduced forced 

expiratory volume in 1 second (FEV1) should trigger 

additional evaluation.

•	 Lung volume assessments are consistent with 

hyperinflation. 

•	 Carbon monoxide diffusing capacity measurement is 

generally normal, especially early in the disease.

•	 Chest x-rays are usually normal but may show 

hyperinflation.

•	 High-resolution computerized tomography scans of 

the chest at full inspiration and expiration often reveal 

heterogeneous air trapping on the expiratory view and 

may demonstrate mosaic attenuation, bronchial wall 

thickening, cylindric bronchiectasis, and/or scattered 

ground glass opacities.

•	 Lung biopsies are not generally required for diagnosis, 

but may reveal evidence of constrictive bronchiolitis 

obliterans. Sometimes the term clinical bronchiolitis 

obliterans is used for patients who have medical 

test findings consistent with the disease constrictive 

bronchiolitis obliterans but do not have confirmatory 

biopsy results.

Perform Medical Management

Patients with flavoring-related lung disease should be 

removed from further exposure to diacetyl or similar 

flavoring chemicals. Removal from exposure does not 

usually result in significant improvement, but the level 

of impairment often stabilizes. No specific treatment has 

been shown to reverse abnormalities in lung function. 

Symptomatic therapy should be provided as appropriate.

Healthy bronchiole (left) and bronchiole of an affected worker (right) 

showing patterns of constrictive bronchiolitis obliterans. 

Ask About Symptoms

Symptoms are not present in all cases. When present, 

symptoms can range in severity. The main respiratory symptoms experienced by workers include:

•	 Cough (usually without phlegm)

•	 Shortness of breath on exertion

•	 Wheezing

Other symptoms experienced by some workers include: 

•	 Fever, night sweats, or weight loss

•	 Frequent or persistent eye, nose, throat, or skin 

irritation

In cases of flavoring-related lung disease, respiratory symptoms do not typically improve when the worker goes home 

at the end of the workday, on weekends, or on vacations. The 

symptoms often have a gradual onset but can occur suddenly. Work-related exposure to butter flavoring chemicals 

might also lead to asthma or exacerbate pre-existing asthma. 

Image courtesy of Jupiter Images