Obliterative
bronchiolitis in five former
coffee processing employees at a single workplace prompted an exposure study of current workers. Exposure characterization was performed by observing processes, assessing the ventilation system and pressure relationships, analyzing headspace of flavoring samples, and collecting and analyzing personal breathing zone and area air samples for
diacetyl and
2,3-pentanedione vapors and total inhalable dust by work area and job title. Mean airborne concentrations were calculated using the minimum variance unbiased estimator of the arithmetic mean. Workers in the grinding/packaging area for unflavored
coffee had the highest mean
diacetyl exposures, with personal concentrations averaging 93 parts per billion (ppb). This area was under positive pressure with respect to flavored
coffee production (mean personal
diacetyl levels of 80 ppb). The
2,3-pentanedione exposures were highest in the flavoring room with mean personal exposures of 122 ppb, followed by exposures in the unflavored
coffee grinding/packaging area (53 ppb). Peak 15-min airborne concentrations of 14,300 ppb
diacetyl and 13,800 ppb
2,3-pentanedione were measured at a small open hatch in the lid of a hopper containing ground unflavored
coffee on the mezzanine over the grinding/packaging area. Three out of the four bulk
coffee flavorings tested had at least
a factor of two higher
2,3-pentanedione than
diacetyl headspace measurements. At a
coffee processing facility producing both unflavored and flavored
coffee, we found the grinding and packaging of unflavored
coffee generate simultaneous exposures to
diacetyl and
2,3-pentanedione that were well in excess of the NIOSH proposed RELs and similar in magnitude to those in the areas using a flavoring substitute for
diacetyl. These findings require physicians to be alert for obliterative
bronchiolitis and employers, government, and public health consultants to assess the similarities and differences across the industry to motivate preventive intervention where indicated by exposures above the proposed RELs for
diacetyl and
2,3-pentanedione.