It’s official. The National Institute for Occupational Safety and Health (NIOSH) has officially made a recommendation to limit the exposure of workers to flavoring compounds. And don’t think it’s just for microwave popcorn plants!

NIOSH contends that workers at risk of developing obliterative bronchiolitis (OB) from exposure to diacetyl and 2,3-pentanedione. OB is 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. OB is most famously associated with microwave popcorn plants but, in fact, can be an issue in any flavoring manufacturing plant or industrial or commercial facility where workers are exposed to the flavorings.

Who’s Affected?

Exposure to these flavoring compounds is not limited to microwave popcorn and flavoring plants. According to NIOSH, other industries with potential exposure to butter flavoring chemicals include:

  • Snack foods (e.g., chips, pretzels),
  • Commercial and retail bakeries (e.g., cakes, cookies, bread),
  • Retail baking mix production,
  • Margarine and other vegetable oil-based cooking products,
  • Butter and other dairy products,
  • Cigarette and e-cigarette manufacturers,
  • Candy manufacturers,and
  • Coffee processing facilities

In addition, the use of butter-flavored cooking oil products to prepare meals in restaurants may also lead to worker exposures.

Let’s Get REL

On the basis of a quantitative risk assessment of data collected in a series of NIOSH health hazard investigations, NIOSH concluded that employee exposure to diacetyl is associated with a reduction in lung function.

NIOSH has established a recommended exposure limit (REL) 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/day during a 40-hour workweek). NIOSH also recommended 15-minute short-term exposure limits (STELs) at 25 ppb for diacetyl and 31 ppb for 2,3-pentanedione.

In addition, to ensure that employee exposures are routinely below the REL for diacetyl, NIOSH also recommends using an action level (AL) of 2.6 ppb with the exposure monitoring program to ensure that all control efforts (engineering controls, medical surveillance, and work practices) are in place and working properly.

What’s Next?

At this point, the Occupational Safety and Health Administration (OSHA) deals with diacetyl and other flavoring exposure under the General Duty Clause and directives. With the NIOSH REL now official, it may be that an OSHA permissible exposure limit (PEL) is in the future.

Most flavorings are complex mixtures of natural and manmade substances. The U.S. Food and Drug Administration (FDA) evaluates flavoring ingredients to determine whether they are “generally recognized as safe” (GRAS) to be eaten. However, according to NIOSH, even if they are safe to eat, these ingredients might still be harmful to breathe in the forms and amounts to which food and chemical industry workers may be exposed.

Given the complexity of flavorings mixtures and the lack of health data for many of the component materials, identifying the relative contributions of individual substances to causing flavoring-induced lung disease is a difficult challenge. The RELS for diacetyl and 2,3-pentanedione may just be the beginning. NIOSH has noted that the flavorings industry has estimated that over 1,000 flavoring ingredients have the potential to be respiratory hazards because of possible volatility and irritant properties.

What to Do at Your Facility

There are engineering and work practices are available to control diacetyl and 2,3-pentanedione exposures below the recommended exposure limits. NIOSH recommends a hierarchy of controls, including elimination, substitution, engineering controls, administrative controls, and the use of personal protective equipment should be followed to control workplace exposures.

Tips to Prevent Worker Exposure to Flavorings

The National Institute for Occupational Safety and Health (NIOSH) has officially made a recommendation to limit the exposure of workers to flavoring compounds.

NIOSH has established a REL 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/day during a 40-hour workweek). NIOSH also recommended 15-minute short-term exposure limits (STELs) at 25 ppb for diacetyl and 31 ppb for 2,3-pentanedione.

In addition, to ensure that employee exposures are routinely below the REL for diacetyl, NIOSH also recommends using an action level (AL) of 2.6 ppb with the exposure monitoring program to ensure that all control efforts (engineering controls, medical surveillance, and work practices) are in place and working properly.

What to Do at Your Facility

There are engineering and work practices are available to control diacetyl and 2,3-pentanedione exposures below the recommended exposure limits. NIOSH recommends a hierarchy of controls including elimination, substitution, engineering controls, administrative controls, and the use of personal protective equipment should be followed to control workplace exposures.

Seven Standard Precautions

NIOSH recommends these seven standard engineering controls to keep diacetyl and 2,3-pentanedione exposures below the RELs.

  • Isolate rooms where flavorings or flavoring compounds are handled from the rest of the plant with walls, doors, or other barriers.
  • Maintain flavoring mixing rooms and other areas where flavorings are handled under negative air pressure relative to the rest of the plant. Check status with airflow indication equipment. Install hood static pressure gauges (manometers) near hoods to provide a way to verify proper hood performance. Check pressure frequently to ensure that the system is operating properly compared to baseline. Check hood face velocities, and capture velocities frequently to ensure that system is performing as designed.
  • Ensure that employees are properly trained on the use of the controls if using proximity switches for fan activation. Consider installing a control “on/off” light to indicate the status of the exhaust fan.
  • Place hoods away from doors, windows, air supply registers, and aisles when possible to reduce the impact of cross drafts.
  • Provide supply air to production rooms to replace most of the exhausted air.
  • Direct exhaust air discharge stacks away from air intakes, doors, and windows.
  • Inspect hoods and enclosures for signs of damage or leaks (rust/corrosion, open access doors, etc.) and obstructions (paper, gloves, rags, etc.). Where possible, use screens to prevent foreign objects from being pulled into the system through openings (slots, hood faces, etc.).

For more information or assistance with your Environmental and Health & Safety regulatory compliance needs, contact Ralph Carito at Total Environmental & Safety, LLC (Total) at rcarito@TotalEnviron.com or 908-442-8599.