Health hazard evaluation report, HETA-99-0311-2790, DaimlerChrysler Transmission Plant, Kokomo, Indiana.
On August 9, 1999, NIOSH received a joint management/union (International Union, United Automobile, Aerospace, and Agricultural Implement Workers of America) health hazard evaluation (HHE) request concerning respiratory symptoms occurring among employees of Department 8700 at the DaimlerChrysler transmission plant in Kokomo, Indiana. NIOSH representatives made site visits to the Kokomo plant in August and September 1999. The concerns which were the basis for the HHE request began when a number of employees reported respiratory symptoms on June 3, 1999, and continued to the time of the HHE request with intermittent "outbreaks" of reported symptoms among Department 8700 employees. During the NIOSH site visits, NIOSH representatives observed work and manufacturing processes, reviewed recent industrial hygiene sampling results and interventions performed by management and the local union, performed bulk material and air sampling in Department 8700 and Department 7700 (another machining area using the same metalworking fluid [MWF]), reviewed medical records of Department 8700 workers, and administered a symptom questionnaire to workers in Departments 8700, 7500, and 7700. The levels of Gram-negative bacteria in bulk MWF samples ranged from (10)5 - (10)8 colony-forming units per milliliter (cfu/mL). The endotoxin concentrations were generally around (10)5 endotoxin units (EU)/mL. The results of the area air samples taken during the August 1999 site visit revealed trace amounts of volatile organic contaminants, none of which were judged likely to be primarily related to the reported health effects. Among the 70 personal breathing zone (PBZ) samples collected for MWF aerosol during the September 1999 site visit, the concentrations in four samples equaled or exceeded the NIOSH Recommended Exposure Limit (REL) of 0.4 milligrams per cubic meter; one of these samples was from Department 8700, three were from Department 7700. Medical records were reviewed for 71 Department 8700 workers. The most prevalent symptoms were asthma-like symptoms, with 72% of these 71 workers reporting cough, 45% reporting shortness of breath, 39% reporting chest tightness, and 13% reporting wheezing. The medical records revealed two persons with new-onset asthma associated with a work-related pattern of symptoms, two persons with exacerbations of pre-existing asthma, and six other workers with asthma-like conditions. Overall, 229 (50%) of 462 employees in the three departments surveyed participated in the questionnaire survey (by department: 7500 -68/80[85%]; 7700 - 95/135[70%]; 8700 - 66/247[27%]). A variety of symptoms, both respiratory and non-respiratory, were reported by employees of the three machining departments. Persistent cough was the symptom most commonly reported among participants from Department 8700 (reported by 62% of participants). The medical record review confirmed several cases of asthma (both new-onset and aggravation of pre-existing asthma), as well as respiratory symptoms, occurring among employees of Department 8700. No single aspect of the Department 8700 manufacturing process, however, was determined to be clearly related to the cluster of illnesses which were first reported in June 1999. Our air sampling indicates that exposure to MWF aerosol alone in Department 8700 is not likely the cause for the observed increase in reported symptoms. The bulk sampling indicates that microbial contamination is a continuing problem in the MWF of Department 8700. To address the symptoms which were the basis for this HHE request, a recommendation is made concerning continued systematic monitoring of reported health problems. This report also provides recommendations concerning maintenance and cleaning of central MWF systems, machine sumps, and flumes and further air sampling as components of the MWF safety and health program at Kokomo.