Health hazard evaluation report: HETA-2007-0327-3083, findings from industrial hygiene air sampling, ventilation assessment, and a medical survey at a facility that manufactures flavorings, modified dairy products, and bacterial additives, Chr. Hansen, Inc., New Berlin, Wisconsin.
Background: Workers at Chr. Hansen, Inc., in New Berlin, Wisconsin, requested that NIOSH perform a health hazard evaluation to investigate the risk of respiratory and eye problems from exposures to diacetyl, butter flavorings, cheese flavorings, enzymes, colors, bacterial cultures, and cleaning agents. The plant has separate rooms for the production of the following products and product types: 1. Starter distillate, a liquid which contains the flavoring chemical diacetyl, is produced in the starter distillate room. 2. CHY-MAXR, a standardized solution of the enzyme chymosin (produced at another plant) is diluted and packaged in the enzymes room; starter distillate is also diluted and packaged in this room. 3. Cheese, dairy, and other flavors and cheese products are produced in the flavors room. 4. Powdered flavors and colors are produced through a spray drying process in the spray dry room. 5. Bacterial blends for use in foods intended for human consumption are produced in the human health room. (Flavorings are not used or produced in this room.) 6. Bacterial blends for use as feed supplements for farm animals are produced in the animal health rooms. (Flavorings are not used or produced in this room.) Exposures related to production of flavorings are of particular concern to NIOSH. Previous NIOSH investigations have identified evidence of a severe disease of the small airways in the lung (bronchiolitis obliterans) among workers exposed to butter flavoring chemicals in microwave popcorn plants and among production workers in flavoring manufacturing plants. Exposures to enzymes and other organic dust are also of concern due to their potential to cause lung disease in some individuals. Workplace exposures to enzymes can cause asthma and other allergic problems. Repeated exposure to organic dusts (materials from living things such as plants, animals, bacteria, or fungi) can cause hypersensitivity pneumonitis, another serious lung disease. Assessment: NIOSH staff visited the plant initially in September 2007 to meet with management and workers, conduct an initial walkthrough of the plant, learn about production processes, and do preliminary air sampling. NIOSH staff returned to the plant in December 2007 to do a detailed ventilation assessment and industrial hygiene air sampling, and to conduct a medical survey which included a questionnaire and lung function testing with spirometry. All current workers in production areas, the QC laboratory, the warehouse, and maintenance were invited to participate in the medical survey. For analyses of the medical survey results by type of potential exposure in the plant, workers were classified as follows: 1. Flavoring workers: Current workers with potential exposure to diacetyl and other flavoring-related chemicals in the starter distillate, enzymes, flavors, or spray dry rooms, the QC laboratory, or in maintenance work. 2. Bacterial products workers: Current workers with potential exposure to bacteria and other organic dusts in the animal health or human health rooms. 3. Warehouse workers. Results: Air sampling showed diacetyl air concentrations in the spray dry, starter distillate, and flavors rooms and in the quality control laboratory that were similar to those measured at some flavoring plants and microwave popcorn plants where some workers have developed severe lung disease likely caused by exposure to diacetyl and possibly other flavoring chemicals. This included both average air concentrations over the work shift and peak air concentrations during specific tasks. The atmospheric pressure in the spray dry and flavors rooms was neutral to positive relative to the warehouse; as a result, movement of air contaminants from those rooms into the warehouse is possible. The Torit® local exhaust ventilation unit used during packaging of finished product in the spray dry room allowed some of the captured dust to escape back into the room air. One worker in the flavoring worker group had mild fixed airways obstruction on spirometry testing. Although this finding might be related to flavoring chemical exposures, additional medical tests are required to establish if a particular lung disease is present and the likely cause; information from additional medical evaluation was not available to NIOSH investigators. Among nine current and former workers in flavoring production areas who reported chest symptoms from work exposures, three workers reported chest symptoms from exposure to enzymes; three workers reported chest symptoms from exposure to acids; one worker reported chest symptoms from exposure to diacetyl; and one worker reported chest symptoms from exposure to encapsulated starter distillate. One worker reported eye burning from diacetyl and starter distillate. Air sampling in the animal health large and intermediate packaging rooms showed intermittent peak exposures to dust during ingredient mixing and product packaging activities. For some processes, local exhaust ventilation in these rooms did not adequately control dust exposures. Of ten workers in the animal and human health rooms who participated in the medical survey, five reported post-hire skin problems, four reported chest symptoms from exposures, and three reported work-related eye and nasal symptoms. Two of the four with chest symptoms reported that these occurred with exposure to Biomax® and other powders. Spirometry tests in two animal health workers showed restriction, a decreased ability to fully expand the lungs. One of the two workers with restriction also reported weekly episodes of unusual tiredness and fatigue and monthly episodes of fever, chills, or night sweats. These symptoms in an individual with restriction on spirometry can be due to hypersensitivity pneumonitis, a lung disease which occurs in a small percentage of individuals exposed to organic dusts. Additional medical tests are necessary for a physician to establish if an individual has this disease. Conclusions and Recommendations: The levels of diacetyl measured in flavoring production areas at the Chr. Hansen plant may be high enough to put workers at risk of developing severe lung disease. Because flavoring-related lung disease can occur after only several months of exposure and can rapidly progress to severe irreversible disease, uncontrolled exposures should be minimized. Workers in the animal and human health rooms may also be at risk for respiratory symptoms and disease from exposure to organic dust. The Recommendations section of this report contains detailed guidance on what Chr. Hansen mangers should do to decrease exposures in all production rooms, the quality control laboratory, and the warehouse to minimize the potential for workers to develop respiratory and other health effects. The following approaches for prevention are addressed: ventilation improvements, administrative and work practice changes, use of respirators and other personal protective equipment, worker education, and medical monitoring with regularly scheduled spirometry tests.