Hazard evaluation and technical assistance report no. HETA 97-0141-2819: Special Metals Corporation, Princeton Powder Division, Princeton, Kentucky.
The National Institute for Occupational Safety and Health (NIOSH) conducted a health hazard evaluation (HHE) at Special Metals Corporation, Princeton Powder Division, Princeton, Kentucky. NIOSH conducted this HHE at the request of employees at that facility who were concerned about the possible formation of hexavalent chromium (Cr[VI]) in the specialty alloy production operations, and of the potential health hazards from exposures to this and other materials associated with those operations. Health effects mentioned in the request included nose bleeds, sinusitis, gastric disturbance, and fatigue. In response to this request, NIOSH investigators conducted an initial environmental and medical investigation at the site on July 23 and 24, 1997. NIOSH investigators collected 5 personal breathing-zone (PBZ) and 4 area air samples for Cr(VI), 7 PBZ and 4 area air samples for heavy metals, and 6 residual process bulk-material samples for Cr(VI). Two areas of the facility were also evaluated for noise levels. Based upon the initial findings, the NIOSH investigators determined that a follow-up visit was necessary to better characterize workers' exposures to several of the metals used at the facility, by conducting biological monitoring and additional environmental monitoring. The follow-up visit was conducted on September 17-18, 1998. During this visit, NIOSH investigators collected a total of 40 PBZ and 8 area air samples for Cr(VI), 38 PBZ and 7 area air samples for heavy metals, 4 bulk-material samples for Cr(VI), 2 PBZ air samples for respirable crystalline silica, 1 area "bulk-air" sample for crystalline silica, and 2 bulk-material samples for crystalline silica. In general, the highest PBZ air sample concentrations of nickel, cobalt, total chromium, and niobium were found in the furnace bay, laboratory, and inert screening areas. During the initial survey, 1 air sample (collected in the breathing zone of the laboratory assistant) exceeded the Occupational Safety and Health Administration (OSHA) Permissible Exposure Limit (PEL) for nickel (1000 micrograms per cubic meter [µg/m 3 ]) and cobalt (100 µg/m 3 ). Five PBZ air samples exceeded the NIOSH Recommended Exposure Limit (REL) for nickel (15 µg/m 3 ) and 1 PBZ air sample exceeded the REL for cobalt (50 µg/m 3 ). Two PBZ air samples exceeded the American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Values (TLV) for cobalt (20 µg/m 3 ). One PBZ air sample exceeded the NIOSH REL and the ACGIH TLV for total chromium (500 µg/m 3 ). Bulk sample analysis revealed that Cr(VI) is present in the facility, however all PBZ air sample concentrations for Cr(VI) were below relevant evaluation criteria. During the follow-up survey, 2 air samples (collected in the breathing zone of the laboratory assistant and furnace operator's helper) exceeded the OSHA PEL for nickel and cobalt. Twenty-two PBZ air samples exceeded the NIOSH REL for nickel and four PBZ air samples exceeded the REL for cobalt. Seven PBZ air samples exceeded the ACGIH TLV for cobalt. All results for total chromium were below relevant evaluation criteria. Bulk sample analysis confirmed the initial survey results that Cr(VI) is present in the facility. However, all Cr(VI) PBZ air samples collected were below relevant evaluation criteria. All samples collected for crystalline silica resulted in nondetectable concentrations. Sample results in many cases represent potential exposures, rather than actual inhalation exposures, due to employees wearing respirators. During the follow-up evaluation, all chromium and cobalt levels in urine were well below their respective biological exposure indices. There is no biological exposure index for nickel in the United States. Urine nickel levels, however, suggested that all 48 participating employees may have been exposed to nickel at work. We found a potential health hazard from exposure to nickel and cobalt at this facility. Air samples showed potential employee exposures to nickel and cobalt exceeding relevant evaluation criteria. Bulk and air samples indicated the presence of Cr(VI) in various production areas of the facility, however all personal breathing zone air samples collected for Cr(VI) were below relevant evaluation criteria. Urine samples showed evidence of workplace exposure to nickel in all employees, and suggested that low levels of workplace exposure to chromium may be occurring in a small number of workers, but offered no convincing evidence of workplace exposure to cobalt. Use of respirators (by many of the potentially highest-exposed workers) reduced actual inhalation exposures, as well as absorbed doses. Suggestions to improve the health and safety of employees in this facility, through the use of administrative controls, personal protective equipment (PPE) and particularly through the use of engineering control measures to reduce or eliminate reliance on PPE, are presented in the Recommendations section of this report.