Flavorings-Related Lung Disease: Questions and Answers
Questions and Answers
What is a Criteria Document?
Criteria documents are one of many ways NIOSH publishes recommendations about workplaces. A criteria document contains a critical review of the scientific and technical information about the prevalence of hazards, the existence of safety and health risks, and the adequacy of control methods. Criteria documents also contain recommendations to minimize safety and health risk, and include recommended workplace exposure limits and appropriate preventive measures to reduce or eliminate adverse health effects. This includes helpful guidance on engineering controls, hazard communication, personal protective equipment, and medical screening and surveillance.
What has NIOSH found in the coffee industry?
Workers at coffee roasting and packaging facilities may be at risk for respiratory disease. NIOSH investigators published a paper in the American Journal of Industrial Medicine about a health hazard evaluation at a coffee roasting and packaging facility that had five former workers with obliterative bronchiolitis [Bailey et al. 2015]. The coffee facility produced unflavored and flavored coffee. All the workers diagnosed with obliterative bronchiolitis had worked in the flavoring area at some point during their employment at the facility. Current workers at the facility during the health hazard evaluation had excess shortness of breath and obstruction on spirometry (meaning air is exhaled from the lungs more slowly than normal), which are both consistent with undiagnosed lung disease. As of July 2018, no cases of obliterative bronchiolitis have been reported in employees at coffee roasting and packaging facilities that do not flavor coffee.
How are workers exposed to diacetyl and 2,3 pentanedione in the coffee industry?
Diacetyl and 2,3-pentanedione are naturally produced and released when coffee beans are roasted. Grinding roasted coffee beans produces greater surface area for the off-gassing of these and other chemicals, which can contribute to worker exposures. Workers can also be exposed to diacetyl and 2,3-pentanedione when flavoring coffee.
How are exposures to diacetyl and 2,3-pentanedione identified?
Air sampling for diacetyl and 2,3-pentanedione [OSHA 2008; OSHA 2010; LeBouf and Simmons 2017] during specific tasks, such as roasting, grinding, packaging, opening storage bins or containers with roasted coffee beans, and pouring and adding flavorings, is an important way to identify where exposures may occur and for targeting workplace interventions (e.g., engineering controls, ventilation changes).
Because roasted coffee is known to emit volatile organic compounds (VOCs) and carbon monoxide (CO), real-time monitoring for total VOCs and CO may be useful. Areas where higher concentrations of total VOCs or CO are measured would benefit from further sampling to characterize specific exposures to alpha-diketones and help prioritize interventions to lower exposures to diacetyl and 2,3-pentandione (and carbon monoxide).
What should be done if elevated concentrations of diacetyl or 2,3-pentanedieone are identified?
If air sampling in coffee roasting and packaging facilities identifies concentrations of diacetyl or 2,3-pentanedione above NIOSH RELs, steps should be taken to lower exposure. Employees may need to wear appropriate fit-tested respirators until workplace interventions have been put into place and shown to reduce air concentrations in follow-up air sampling. Additionally, a medical surveillance program that includes health questionnaires and breathing tests (e.g., spirometry) may be indicated to screen for respiratory symptoms or abnormalities in employees.
Are workers and customers in coffee cafés also at risk?
As of July 2018, no cases of obliterative bronchiolitis have been reported in coffee café workers. The exposures to diacetyl and 2,3-pentanedione that coffee production and café workers may face on the job are likely very different from each other and from those of consumers entering coffee shops or drinking coffee. We do not currently recommend that air levels of diacetyl or 2,3-pentanedione be routinely measured in coffee cafés.
Cafés may be stand-alone or co-located with coffee roasting and packaging facilities. Café employees frequently grind roasted coffee beans. Grinding increases the surface area of coffee allowing for increased off-gassing of compounds including diacetyl, 2,3-pentanedione, carbon monoxide, and carbon dioxide. However, the amount of coffee ground in cafés is typically smaller than in industrial size coffee roasting and packaging facilities. Still, we recommend that café employees do not place their faces right in front of or right above freshly ground coffee. Also, an adequate supply of outdoor air, typically delivered through the heating, ventilation, and air-conditioning (HVAC) system is necessary in any indoor environment to dilute pollutants that are released by equipment, building materials, furnishings, products (e.g., coffee), and people. To prevent buildup of contaminants in the air, we recommend that coffee cafés do not recirculate 100 percent of air from café spaces without bringing in any outdoor air. Also, if cafés are co-located with a roasting and packaging facility, the café’s ventilation system should not recirculate air from the production spaces.
The American National Standards Institute (ANSI) and ASHRAE have developed consensus standards and guidelines for HVAC systems. ANSI/ASHRAE 62.1-2016 recommends outdoor air supply rates that take into account people-related sources as well as building-related sources. While there are no specific recommendations in the standard for coffee cafés, there are several similar spaces that can be used as effective guidance. For restaurant dining rooms, café/fast-food dining, and bars and cocktail lounges, 7.5 cubic feet per minute (cfm)/person is recommended for people-related sources, and an additional 0.18 cfm for every square foot (cfm/ft2) of occupied space is recommended to account for building-related sources. To find rates for other indoor spaces, refer to Table 220.127.116.11, which is found in ANSI/ASHRAE 62.1-2016 [ANSI/ASHRAE 2016].
We will update this webpage as we learn more about worker exposures to alpha-diketones (i.e., diacetyl, 2,3-pentanedione) in coffee cafés.
What can coffee roasting and packaging companies do to minimize workers’ exposures to of diacetyl and 2,3-pentanedione?
If elevated levels of diacetyl or 2,3-pentanedione are detected, interventions should be put in place to reduce the levels. The effectiveness of these interventions (e.g., engineering controls, ventilation changes) should be verified by follow-up air sampling.
Employees may need to wear appropriate fit-tested respirators until workplace interventions reduce air levels of diacetyl or 2,3-pentanedione. A medical surveillance program that includes health questionnaires and breathing tests (e.g., spirometry) also may be indicated to screen for respiratory symptoms or abnormalities in employees.
What further research must be done?
NIOSH is working with a number of coffee processing facilities through the health hazard evaluation program, including some with on or offsite cafés. NIOSH is aggregating health and air sampling data collected in NIOSH health hazard evaluations to improve our understanding of respiratory health risks in this industry. NIOSH is also evaluating the efficacy of engineering controls in reducing exposures to diacetyl and 2,3-pentandione during coffee processing activities. Lessons learned during these evaluations will be used to develop effective engineering control strategies that can be utilized in other coffee processing facilities to reduce diacetyl and 2,3-pentanedione exposures.