Who knew that when you are ordering your morning latte, you are possibly putting your barista and others at risk? Well, that’s a conclusion that can be drawn from a recent National Institute for Occupational Safety and Health (NIOSH) report that claims workers at coffee processing facilities risk lung disease due to exposure to airborne particles. The report recommends exposure limits and monitoring procedures to reduce coffee workers’ exposure to such airborne chemicals.
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The new NIOSH report, Coffee Workers at Risk for Lung Disease, contends that workers at coffee processing facilities are at risk of developing obliterative bronchiolitis, an irreversible form of lung disease in which the smallest airways in the lung (the bronchioles) become scarred and constricted, blocking the movement of air. Obliterative bronchiolitis has previously been identified in workers in flavoring manufacturing plants and, most famously, microwave popcorn plants. The offending group of chemicals are diacetyl (2,3-butanedione) and butter flavorings containing diacetyl.
NIOSH claims that diacetyl and 2,3-pentanedione (a diacetyl substitute) are also naturally produced when coffee beans are roasted. Grinding roasted coffee beans produces greater surface area for the off-gassing of these and other chemicals. Coffee roasting facilities package newly roasted coffee in bags fitted with one-way valves or in permeable bags to allow for off-gassing. Alternatively, newly roasted coffee is placed in containers and allowed to off-gas, which can contribute to worker exposures.
NIOSH investigated a particular coffee processing facility where five workers were diagnosed with obliterative bronchiolitis. The agency found elevated levels of butter flavoring chemicals diacetyl and 2,3-pentanedione in the air at the facility and identified three sources:
- Flavoring chemicals added to roasted coffee beans in the flavoring area;
- Grinding and packaging unflavored roasted coffee in a distinct area of the facility; and
- Storing roasted coffee in hoppers to off-gas.
What Should Coffee Facility Employers Do?
NIOSH has proposed a recommended exposure limit of 5 parts per billion (ppb) for diacetyl and 9.3 ppb for 2,3-pentanedione (as a time-weighted average (TWA) for up to 8 hours per day during a 40-hour workweek). NIOSH proposed 15-minute short-term exposure limits (STELs) are 25 ppb for diacetyl and 31 ppb for 2,3-pentanedione.
In addition to TWA and STEL samples, NIOSH has identified air sampling during specific tasks, such as roasting, grinding, packaging, opening storage bins or containers with roasted coffee beans, and pouring and adding flavorings as an important way to identify where exposures may occur and for targeting workplace interventions (e.g., engineering controls, ventilation changes) to reduce contaminant air concentrations.
In addition, employees may need to wear appropriate, fit-tested respirators until these workplace interventions have been put into place and have been shown to reduce air concentrations in follow-up air samplings. Also, 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.