Safety data sheets (SDSs) for several bulk flavorings failed to list hazardous substances, according to National Institute for Occupational Safety and Health (NIOSH) findings. Out of 26 bulk liquid flavorings obtained from two U.S. coffee roasting and packaging facilities, 21 contained diacetyl, and 15 contained 2,3-pentanedione.

Inhalation of diacetyl may lead to obliterative bronchiolitis, a debilitating lung disease. Animal studies of 2,3-pentanedione, a common substitute, have found evidence of similar inhalational hazards.

Of the 26 flavorings tested, 24 came from a single manufacturer. None of the SDSs listed diacetyl and 2,3-pentanedione.

SDS exemptions

Chemical manufacturers, distributors, and importers must provide employers with SDSs under the Occupational Safety and Health Administration’s (OSHA) hazard communication standard. SDSs notify employers of hazardous substances in the chemicals they purchase so they can implement appropriate controls to protect the health and safety of their employees.

However, some substances may not be listed on an SDS for reasons that include:

• They are generally recognized as safe for ingestion by the Food and Drug Administration (however, they may present an inhalation hazard in the workplace);
• They are part of the manufacturer’s trade secrets; or
• They make up less than 1% of all ingredients.

Employers at the two coffee-roasting and packaging facilities asked NIOSH to perform a Health Hazard Evaluation out of concern about occupational exposure to flavoring chemicals and possible risks for respiratory impairment. One facility representative told NIOSH investigators the manufacturer said there was no added diacetyl or 2,3-pentanedione in its flavorings.

The manufacturer later clarified to the facility that diacetyl may occur as a natural by-product of acetoin, which is added to almost all coffee flavors used by the facility.

Workers in food-processing facilities face respiratory hazards due to inhalation of diacetyl and 2,3-pentanedione, which are emitted from bulk materials, especially at elevated temperatures.

Food industry hazards identified

In August 2000, NIOSH investigated cases of obliterative bronchiolitis among former workers of a microwave popcorn plant. The institute determined that artificial butter flavorings added to the popcorn were responsible for causing the disease.

NIOSH later found that flavorings used to produce flavored whole-bean and ground-roasted coffee led to the same lung disease among workers employed in coffee roasting and packaging.

There are no OSHA permissible exposure limits for diacetyl and 2,3-pentanedione. NIOSH has recommended exposure limits be set at an 8-hour time-weighted average (TWA) of 5 parts per billion (ppb) for diacetyl and 9.3 ppb for 2,3-pentanedione in workplace air. It also has recommended 15-minute TWA short-term exposure limits of 25 ppb for diacetyl and 31 ppb for 2,3-pentanedione.

Recommended precautions for employers

NIOSH recommends a series of controls and practices for food-processing employers to prevent or limit diacetyl and 2,3-pentanedione exposures:

• Consider using less hazardous substances;
• Use engineering controls such as closed systems, isolation, or local exhaust ventilation;
• Institute administrative controls, such as good housekeeping, and work practices that limit the release of chemical vapors and dust, minimizing exposure;
• Provide personal protective equipment (respirators) where needed, in addition to engineering or administrative controls;
• Keep containers of flavorings tightly closed when not in use so their contents do not get into the workplace air;
• Isolate mixing and other high-exposure processes from the rest of the workplace, and maintain these work areas under negative air pressure;
• Use the lowest temperatures necessary if heated processes are used;
• Monitor air concentrations of flavoring ingredients;
• Provide breathing tests (spirometry) before the first exposure and on a regular basis to all workers at risk of hazardous exposure to flavorings or their ingredients;
• Monitor the status of workers’ health, tracking potential symptoms or cases; and
• Refer workers for evaluation by a physician if they have abnormal breathing test results, an accelerated drop in test results over time, or persistent symptoms.