Although flavorings are considered safe to eat, they are complex mixtures of chemicals, and the hazards of working with and inhaling many of these chemicals have not been evaluated. Based on several cases of severe lung disease in workers handling diacetyl and other similar chemicals, the Occupational Safety and Health Administration (OSHA) has advised that it may be hazardous to breathe or handle in occupational settings.

Employees that become ill as a result of a workplace hazard reduce productivity and can result in costly workers’ compensation claims. OSHA does not currently have permissible exposure limits (PELs) for most flavoring substances, so it is important for all facilities that manufacture flavorings and food products to understand the hazards they may pose to your workers and take appropriate steps to protect them from exposure and serious respiratory disease, as well as protect your business from unnecessary costs.


Diacetyl is used in the production of many foods and flavorings. The occurrence of severe lung disease among workers in workplaces where diacetyl is manufactured and used has led many manufacturers to reduce or eliminate the amount used in flavorings, foods and beverages. Commonly used alternatives to diacetyl, as well as other chemicals used in flavorings, also pose potential risks. Industries that manufacture flavorings and food manufacturers who use these flavorings should control workers’ exposure and continuously monitor the workplace.

Controlling Exposures

To minimize exposure to hazardous flavoring substances and airborne dust, it is important to implement appropriate control measures. There are several engineering controls employers can implement in the workspace to protect employees:

  • Isolate flavoring production and handling areas with structurally sound walls, doors or other appropriate barriers.
  • Install separate ventilation systems in the production room and all other areas where flavorings or heated flavored products are handled.
  • Maintain negative air pressure in the production room with respect to adjoining or adjacent rooms.
  • Where powder or liquid flavorings are manually blended, weighed, mixed, poured, transferred, packed or handled, install local exhaust ventilation (LEV) systems.
  • Use general dilution ventilation, such as wall or ceiling fans.
  • Reduce the operating temperature of holding and mixing tanks to ambient temperature or the lowest temperature possible.
  • Install tank lids with small openings for adding flavoring substances through funnels.
  • Maintain hoppers under negative air pressure at all times while flavorings are added.
  • Install bag-dumping stations equipped with LEV systems.
  • Use a closed system cleaning process—such as clean-in-place—for tanks and blenders.
  • Keep laboratory hood LEV at a minimum velocity of 100 fpm for liquids and 200 fpm for powders across the opening of the hood.
  • Educate workers on best practices and proper methods for minimizing exposure.

Controlling Work Practices

Methods to control work practices can also prevent exposure to potentially harmful flavoring substances:

  • Restrict access to areas where flavorings are mixed, stored or openly handled only to those who are authorized to work in those areas.
  • Compound or dispense flavorings when few workers are in the area.
  • If possible, obtain flavoring substances in sealed, pre-measured containers suitably sized for routine production batches to eliminate weighing and measuring steps.
  • Instruct workers to seal containers tightly when storing or transferring flavorings.
  • Provide funnels for pouring to reduce exposures, splashes and spillage.
  • Establish standard procedures, including prompt cleanup of spills.
  • Do not allow use of a shovel to transfer powdered substances or the use of compressed air/dry sweeping to clean surfaces.

Monitoring Exposure

Monitoring can provide useful information about each worker’s exposure to flavoring substances and whether control measures are working effectively. Reviewing work processes with an environmental health professional or industrial hygienist can help identify critical areas of exposure. Air should be monitored for airborne diacetyl; 2,3 pentanedione; acetoin; and flavoring substances that have OSHA PELs. For best results, collect air samples in all of the following places:

  • Flavoring production rooms
  • Areas where compounding and packing operations occur
  • Areas where flavorings are handled manually or openly
  • Areas with mixing or storage tanks
  • Areas where maintenance and cleaning is performed
  • Where laboratory use of hazardous chemicals is performed, as according to OSHA standards
  • QA/QC laboratories, facilities or processes that are adjuncts of production operations that perform repetitive procedures to assure reliability of a product or process

Medical Surveillance

A medical examination should be conducted on all newly hired workers before they start work in areas where diacetyl or other food flavoring chemicals are present, including a health questionnaire focused on respiratory symptoms and a history of preexisting lung disease to provide baseline information for comparison during subsequent evaluations.

Often the onset of lung disease occurs very rapidly in workers. For early detection of decreasing or abnormal lung function in workers, include spirometry—which measures the breathing capacity of the lungs—in periodic medical evaluations, and regularly conduct spirometry tests on workers.

If you detect respiratory symptoms or evidence of skin or eye irritation in workers, follow up with further medical evaluation. Choose a health care provider that is familiar with flavoring-related occupational lung disease, and plan to refer workers with rapidly declining lung function to a specialist. Providing physicians with information about occupational exposures to flavoring substances (available on the NIOSH website) and potential health risks helps them diagnose and treat the condition, as well as recommend appropriate workplace restrictions, which may include the following:

  • Use of personal protective equipment
  • Restriction of each worker’s exposure
  • More frequent medical evaluations

OSHA Standards

Facilities that manufacture flavorings or food products containing flavorings are subject to a wide range of OSHA standards. While flavoring chemicals are not specifically addressed in any one OSHA standard, several others do apply and can be used as basis for citations or fines in food product manufacturing facilities:

  • The General Duty Clause requires each employer to provide employees with a workplace free from recognized hazards that are causing or are likely to cause death or serious physical harm
  • OSHA has established permissible exposure limits for a number of hazardous substances, and if airborne concentrations of the hazardous substances after engineering and work practice controls have been implemented, then PPE (such as respirators) must be used.
  • OSHA requires that employers provide applicable and suitable respirators where they have determined the presence of a respiratory hazard and where engineering controls fail to adequately control these hazards. OSHA recommends that employers err on the side of caution when evaluating whether workers need to wear respirators, and the agency requires that employers develop and implement a written respiratory protection program outlining how respirators will be selected, used and maintained.
  • OSHA’s PPE standards require employers to assess whether eye and skin hazards that necessitate the use of PPE are present.
  • OSHA requires certain laboratories to produce a Chemical Hygiene Plan that addresses specific hazards found in the facility and its approach to control them.

The Hazard Communication standard requires employers to inform and train employees on the hazards of chemicals in the workplace.