Health hazard evaluation report: HETA-1996-0232-2776, Met-Tech Industries, Inc., Cambridge, Onio.
On July 24, 1996, the National Institute for Occupational Safety and Health (NIOSH) received a confidential request for a health hazard evaluation at Met-Tech Industries, INC. in Cambridge, Ohio. The company produces roof bolts for the underground coal mining industry. The request listed health problems of burning eyes, heartburn, coughing, sinus problems, sore throats, headaches, and shortness of breath among the workers. Workers attributed symptoms to a metalworking fluid (MWF) used at the automatic plate-stamping presses. The NIOSH medical officer conducted telephone interviews of symptomatic employees during October and November 199; and an on-site medical survey was performed January 26-28, 1997. Environmental sampling was performed November 13, 1996, and February 5-6, 1997. Sampling in the facility to determine 8-hour time-weighted average (TWA) concentrations of airborne metalworking fluids found none to be in excess of the OSHA Permissible Exposure Limit (PEL) and American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value (TLV) of 5 milligrams per cubic meter of air (mg./m3); however all the sample concentrations (area and personal breathing zone) measures gravimetrically at two of the three presses were above the NIOSH Recommended Exposure Limit (REL) of 0.4mg/m3 for the thoracic aerosol. When the thoracic samples were analyzed subsequent to solvent extraction, both of the area and both of the personal breathing zone concentrations at one of the three presses were found to exceed the REL of 0.4 mg/m3. All other air samples analyzed by the same method for MWFs measured concentrations below the REL. Area air sampling for endotoxin indicated most levels were lower that 2 endotoxin units per cubic meter of air (EU/m3) and none exceeded 11.5EU/m3. However, within the MWF supply systems for the presses, gram-negative bacteria, predominantly of the Pseudomonas genus, were present in concentrations ranging from 2.5x10^6 to 2.5x10^8 colony-forming units (CFU) per milliliter of fluid. Endotoxin contamination in these fluids ranged from about 68,000 to 537,000 endotoxin units (EU) per milliliter. Our survey did not indicate that illness(es) such as hypersensitivity pneumonitis were occurring among this workforce. The symptom survey did, however, suggest that there was a high prevalence of chronic respiratory symptoms. Slightly more than one-third of participants met the definition for chronic bronchitis. Respiratory symptoms and level of pulmonary function were not associated with workstation or tenure, both indirect indicators if exposure to the implicated MWF. None of the participants in our survey had a significant (>10%) decline in FEV1 over the work shift. There was a high prevalence of reported work-related skin and eye irritation among workers at the facility. NIOSH investigators determined that a health hazard existed from occupational exposure to metalworking fluid at this facility. Personal breathing zone and area concentrations above the NIPSJ REL for airborne MWFs were measured. Mists, from fluids contaminated with bacteria and endotoxin, were generated at the plate-stamping presses. Although the hypersensitivity pneumonitis was not found among this workforce, a high prevalence of chronic respiratory symptoms was indicated. There was also a high prevalence of reported work related skin and eye irritation among workers. Methods to prevent exposure of workers to MWFs are provided in the recommendations section of this report.
Oil-mists; Metalworking; Metalworking-industry; Hypersensitivity; Metal-industry-workers; Metalworking-fluids; Metalworking; Metalworking-industry; Metal-workers; Microorganisms; Region-5; Respiratory-irritants; Respiratory-system-disorders; Pulmonary-system-disorders; Skin-irritants; Eye-irritants; Eyes; Hazard-Confirmed