Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, HETA 96-0016-2777, 1999 Mar; :1-29
On October 20, 1995, the National Institute for Occupational Safety and Health (NIOSH) received a request for a health hazard evaluation (HHE) at Eagle-Picher Industries, Inc., in Joplin, Missouri. The request was submitted by a representative of the United Steelworkers of America Rubber/Plastic Industry Conference, in Akron, Ohio. The request concerned potential employee exposures to a number of chemical hazards, particularly lithium, mercury, and lead chromate, in various operations at the facility. Following a walkthrough survey at the plant on December 12-13, 1995, the NIOSH investigators focused on lithium exposures in the process room, pill room, and dry room 108; mercury exposures in the pit and pasting room; identifying an orange substance on the walls in the potting area; and investigating the cause of eye irritation in the solder room. NIOSH investigators returned to the plant on April 17, 1996, and conducted another walkthrough survey to plan for two full days of industrial hygiene and biological monitoring of employee exposures to lithium and mercury, which took place on April 18-19, 1996. For lithium, NIOSH investigators conducted an exposure assessment for all day-shift employees working in the process room, the pill room, and dry room 108. The exposure assessment was comprised of biological monitoring, full-shift personal breathing zone air monitoring, and hand-wipe sampling. In addition, a self-administered questionnaire was used to assess other factors that could affect serum lithium concentrations. Collection of serum specimens from 41 participants giving informed consent was conducted near the end of the day shift at the end of a work week, when serum lithium concentrations are expected to be at or near steady state. The geometric mean serum lithium concentration was 1.75 micrograms per liter (ug/l), with a range of "not detected" to 11.2 ug/l. These serum lithium concentrations were well below therapeutic and toxic concentrations established for patients taking lithium medication. Serum lithium concentrations, however, differed by work area, showing that occupational exposure was occurring. Workers in the process room (5.59 ug/l) and pill room (4.14 ug/l) had higher mean concentrations than workers in the dry room (1.09 ug/l). Over a 2-day period, NIOSH industrial hygienists collected full-shift personal breathing zone (PBZ) samples for lithium among 39 employees in the process room, the pill room, and dry room 108. The overall geometric mean concentration of lithium in air was 1.79 micrograms per cubic meter (ug/m3), with a range of "not detected" to 121.8 ug/m3. As with the serum concentrations, the air sampling indicated higher mean exposures for process room (25.9 ug/m3) and pill room workers (15.3 ug/m3) compared with dry-room workers (0.45 ug/m3). On the second day of sampling, hand -wipe samples for lithium were collected from 10 employees in the pill room and 14 employees in dry room 108. Samples were collected as employees left their work to go to lunch. The geometric mean of lithium on the wipe samples was 61.7 g, with a range of 9 to 649 g. The mean result among pill room workers (174.9 g) was higher than those among dry -room workers (29.3 g). Additional environmental samples were collected to address other issues raised in the request. Analysis of a bulk sample of dust collected from a diffuser in the potting area showed that the majority of the sample was composed of a variety of phthalate esters. Bis-phenol A and some of its derivatives, which are consistent with the presence of epoxy resins, were also major components. The presence of the constituents of the potting compounds on the diffuser may indicate that these substances are being recirculated in the workroom air. A wipe sample was collected from the exterior of a duct near the diffuser. The sample was analyzed for metals. Results showed the presence of aluminum, barium, cadmium, cobalt, chromium, copper, iron, lithium, magnesium, manganese, mercury, molybdenum, nickel, lead, phosphorous, silver, titanium, vanadium, yttrium, zinc, zirconium. Two short-term PBZ air samples were collected to assess employee exposure to rosin solder flux decomposition products, specifically aldehydes and formaldehyde. The results indicated that none of these products were present in amounts greater than the limits of detection for the method. Mercury (Hg) exposure monitoring and urine Hg concentrations were determined among workers in the Hg treatment and negative pasting areas. The overall average Hg full-shift time weighted average (TWA) exposure concentration was 18.3 ug/m3, and the TWA exposure concentrations ranged from 3.5 to 48.3 ug/m3. Only 2 of 17 full-shift TWA Hg exposure measurements exceeded the American Conference of Governmental and Industrial Hygienists (ACGIH) TLV for Hg of 25 ug/m3, and both of these were from processors in the negative pasting area. In general, Hg exposures in the negative pasting area were slightly higher than those in the Hg treatment area. No Hg over-exposures were found during short-term, task-based air sampling. Only 1 of 17 workers had a urine Hg concentration above the ACGIH Biological Exposure Index, and the reasoning behind this high level could not be determined in this survey.