NIOSH Evaluates VOCs, Carbon Monoxide in Coffee Packaging Facility
A recently published health hazard evaluation (HHE) report details NIOSH’s assessment of exposures to the volatile organic compounds (VOCs) diacetyl and 2,3-pentadione, as well as carbon monoxide (CO), experienced by workers at a facility where coffee was ground, roasted, and packaged. In July 2023, agency staff visited the facility at the request of management to collect air samples, install a temporary ventilated enclosure around a large coffee grinder, and interview employees about their health concerns.
According to the HHE report, six out of seven personal air samples collected for employees involved with production tasks surpassed NIOSH’s recommended exposure limit (REL) for diacetyl, set at 5 ppb. The highest area concentrations of diacetyl, 2,3-pentadione, and CO were measured near the small coffee grinder. Diacetyl concentrations in this area ranged from 31.6 to 77.3 ppb. Corresponding 2,3-pentadione concentrations ranged from 22.8 to 50.5 ppb, exceeding NIOSH’s REL of 9.3 ppb for the substance. Although the report cautions that the results of area air sampling are not directly applicable to NIOSH RELs, area samples “can highlight areas with higher exposure risk, and the RELs can be used as points of reference.”
Several full-shift continuous air measurements of CO collected near the small grinder exceeded NIOSH’s ceiling limit of 200 ppm. Peak CO measurements taken near the small grinder for each day of the survey ranged from 1,041 to 1,521 ppm. The latter, represented by a single 10-second measurement, surpassed NIOSH’s immediately dangerous to life and health (IDLH) value of 1,200 ppm.
Personal and area air samples indicated that concentrations of diacetyl, 2,3-pentadione, and CO decreased after NIOSH staff installed a ventilated enclosure to control emissions generated by a large coffee grinding machine. For example, roaster operators’ personal air samples decreased from 10.7 ppb to 8.8 ppb for diacetyl and from 7.8 ppb to 5.4 ppb for 2,3-pentadione. Measurements taken inside the enclosure compared with those taken outside of it indicated that the device reduced diacetyl and 2,3-pentadione concentrations by a factor of 16 and CO concentrations by seven- to 12-fold.
As a temporary solution to control CO concentrations near the small grinder, a fan was positioned to blow emissions away from workers’ breathing zones during grinding tasks. This was found to reduce CO concentrations to just below NIOSH’s ceiling limit. However, the report warned that this conclusion was based on the results of one 17-minute sampling period and that the NIOSH ceiling limit for CO may still be exceeded, depending on factors such as coffee roast level or quantity. To more effectively control emissions near the small grinder, NIOSH recommended that the employer work with an engineer to install local exhaust ventilation, as well as a CO monitor to alert employees if concentrations exceeded 200 ppm. If personal air samples for diacetyl and 2,3-pentadione continued to surpass safe levels even after the installation of ventilation near the small grinder, NIOSH urged the employer to provide workers with respiratory protection.
Other recommendations issued by NIOSH included installing permanent ventilation controls around the large grinder, training employees to protect themselves from hazards at the facility, and encouraging employees to report new, persistent, or worsening work-related respiratory symptoms. A PDF of the report may be downloaded from NIOSH’s HHE report database.