Health hazard evaluation report: HETA-2008-0230-3096, report on an investigation of buttermilk flavoring exposures and respiratory health at a bakery mix production facility, General Mills, Los Angeles, California.
On July 8, 2008, the National Institute for Occupational Safety and Health (NIOSH) received a confidential Health Hazard Evaluation (HHE) request to perform an investigation of possible health hazards at the General Mills, Inc. bakery mix facility in Los Angeles, California. The requestors described concerns about respiratory health, including bronchiolitis obliterans which is a rare irreversible lung disease found in some workers exposed to diacetyl in flavorings. They noted exposure to hazardous chemicals, including flavorings containing diacetyl. Prior to their request, the California Division of Occupational Safety and Health (CalOSHA) had visited the facility, performing a limited review under the Flavoring Industry Safety and Health Evaluation Program. NIOSH investigators were aware that a buttermilk flavoring containing 15-20% diacetyl was used at the facility in the past, which had been re-formulated and reported to contain less than 1 percent diacetyl. NIOSH investigators conducted telephone interviews with workers, union representatives, an inspector from CalOSHA familiar with the facility, and company management and safety officials. In September-October 2008, NIOSH staff conducted a medical survey at the plant consisting of an interviewer-administered questionnaire and lung function testing with spirometry before and after bronchodilator administration; they also observed production processes, collected bulk samples of flavorings, and measured concentrations of airborne contaminants in all areas of the facility. In May 2009, NIOSH staff performed additional air sampling to quantitate levels of a diacetyl substitute, 2,3-pentanedione. NIOSH staff conducted spirometry on 24 (59%) of the current employees, including 19 (70%) production workers. None of the workers tested with spirometry had fixed airways obstruction as seen in flavoring-related bronchiolitis obliterans. Participants had higher than expected rates of shortness of breath, physician-diagnosed asthma, and a restrictive pattern on spirometry, compared to U.S. adults. Some participants reported symptoms with a work-related pattern. Analytical results of headspace bulk samples of currently used liquid and powdered flavorings indicated that five of six contained the alpha-diketone substitute compound, 2,3-pentanedione; four contained diacetyl, three contained acetoin, and three contained other alpha-diketones. None of the applicable Material Safety Data Sheets for the evaluated bulk flavorings listed diacetyl or its alpha-diketone substitutes. Only one MSDS listed acetoin. Results of personal and area air samples indicated quantifiable concentrations of 2,3-pentanedione during handling of the re-formulated liquid buttermilk flavoring and during production of a bakery mix that contained the re-formulated flavoring. No diacetyl, acetoin, or other alpha-diketones were above minimum detection limits in workplace air for time-weighted samples. The toxicology of diacetyl substitutes is only now being studied. Because 2,3-pentanedione, 2,3-hexanedione, and 2,3-heptanedione all share the same functional alpha-diketone group as diacetyl, these compounds may also share diacetyl's mechanism of toxicity. Until more is known about 2,3-pentanedione and other alpha-diketone compounds, they should not be assumed to be safe. A "safe" level of diacetyl has not been established, and even low levels of diacetyl are potentially hazardous. Management should continue to limit exposures to flavorings through a combination of engineering controls, work practices, and respiratory protection. Workers should report symptoms to their personal physician and to a designated individual at the workplace.
Respiratory-system-disorders; Pulmonary-system-disorders; Pulmonary-function; Lung-disorders; Food-additives; Food-processing-workers; Food-processing-industry; Food-processing; Spirometry;
Author Keywords: Flavoring; diacetyl; 2,3-pentanedione; fixed obstruction; bronchiolitis obliterans; restrictive lung disease