Evaluation Of Employee Exposures At An Automobile Parts Manu

Evaluation of Employee Exposures at an Automobile Parts Manufacturing Facility

For this research paper assignment, you have been asked to perform an evaluation of employee exposures at a small automobile parts manufacturing facility. The manufacturing processes include two metal presses, two machining stations, three welding stations, a small paint booth, and a shipping/receiving area. There are two employees working at each press, one person working at each machining station, one person working at each welding station, two people working in the paint booth, and four employees working in the shipping/receiving area. The facility uses various materials and equipment that present potential hazards, including noise, chemical exposures, and mechanical hazards. The 2,000-ton press is identified as the greatest noise source. The machining area employs a metal working fluid, while welding on stainless steel generates hexavalent chromium. The painting booth utilizes powder coating, and solvent cleaning involves xylene and methyl ethyl ketone (MEK). Additionally, one employee uses 1,3-butadiene for cleaning paint booth nozzles. The facility operates with electric forklifts that transmit risks related to material handling. All employees work uniform 8-hour shifts.

Paper For Above instruction

Part 1: Identification of Hazards, Their Location, and Affected Employees

The primary step in evaluating workplace hazards is to identify potential and actual hazards using the anticipation and control principles outlined in occupational health and safety frameworks. In this facility, significant hazards include noise, chemical exposures (solvents, metalworking fluids, chromium compounds, and 1,3-butadiene), mechanical hazards from presses, and ergonomic risks from material handling.

Noise hazards are prominent due to the operation of the large 2,000-ton press, with reported noise levels reaching 100 dBA during setup and cleanup. OSHA’s permissible exposure limit (PEL) for noise is 90 dBA for an 8-hour TWA, making these levels potentially hazardous. Employees working near the press, including setup and cleanup operators, are at risk. Additionally, the shipping/receiving forklift operators and employees in the paint booth are exposed to elevated levels, as indicated by noise measurements of 82.0, 80.0, and 82.0 dBA. These are potential hazards because extended exposure could cause hearing loss, necessitating further evaluation and engineering controls.

Chemical hazards include solvents such as xylene and MEK, used in cleaning operations, and 1,3-butadiene, used for cleaning nozzles. The SDS indicates that xylene and MEK are volatile organic compounds (VOCs) with potential inhalation risks. Xylene concentrations recorded at 24 ppm, and MEK at 60 ppm, are below OSHA’s PEL of 100 ppm for xylene (8-hour TWA) and 250 ppm for MEK. The presence of 1,3-butadiene at 6.0 ppm exceeds OSHA’s PEL of 1 ppm (8-hour TWA), representing an actual hazard requiring intervention.

Hexavalent chromium exposure during welding is another serious concern (8.5 µg/m3), which exceeds OSHA’s PEL of 5 µg/m3 (8-hour TWA). This chemical hazard is identified at welding stations, where stainless steel welding occurs, with potentially harmful inhalation exposure risks for welders. This is an actual hazard given the measured concentrations surpass permissible limits.

The use of metal working fluids in machining introduces the risk of mineral oil mist, with the highest recorded concentration of 1.1 mg/m3. OSHA’s PEL for mineral oil mist is 5 mg/m3, indicating the hazard is present but not exceeding limits, though continuous monitoring is advisable due to potential cumulative effects.

Additional hazards include mechanical risks from presses and forklifts, which pose physical injury risks especially if safety protocols are not strictly followed. The employees operating or working nearby these machines are potentially at risk, although these are more mechanical than chemical hazards.

Locations and Affected Employees

The hazards are primarily located in specific areas: the press area (noise and mechanical risk), machining stations (metalworking fluids), welding stations (hexavalent chromium), painting booth (solvent vapors), and shipping/receiving zones (noise, mechanical hazards). Employees working directly at these sites are most at risk:

  • Press operators (2 workers per press)
  • Machining operators (2 workers)
  • Welders (3 workers)
  • Paint booth operators (2 workers)
  • Employees involved in cleaning nozzles and maintenance (1 worker)
  • Forklift operators (2 workers)
  • Shipping/receiving employees (4 workers)

Overall, approximately 16 employees are potentially exposed to one or more hazards, requiring targeted controls and further monitoring to ensure safety.

Part 2: Measurement of Personal Exposures and Sampling Methodology

To accurately assess chemical exposures, personal sampling must align with OSHA and NIOSH methods. For chemical hazards such as solvents, hexavalent chromium, and 1,3-butadiene, specific sampling media and analytical techniques are recommended.

Xylene and MEK (VOCs) can be sampled using charcoal sorbent tubes, which are OSHA Method ID 143 (NIOSH Method 1501). For oxygenated VOCs, sampling at a flow rate of 0.2 L/min for a duration of 8 hours allows for representative TWA measurements. The sampling train involves a charcoal tube connected to a calibrated personal sampling pump, with flow rate calibration performed before and after sampling using a bubble or dry cal. Post-sampling analysis involves desorption with carbon disulfide and gas chromatography with flame ionization detection (GC-FID). This method provides reliable quantification of VOC concentrations in workplace air.

Hexavalent chromium requires sampling using a personal breathing zone filter followed by extraction and analysis via atomic absorption spectroscopy (AAS) or inductively coupled plasma mass spectrometry (ICP-MS) per OSHA Method ID 208. Sampling flow rates are typically 1-2 L/min, with durations aligning with work shifts (up to 8 hours). Calibration involves using standards traceable to NIST. The choice of ICP-MS offers high sensitivity for low-level hexavalent chromium detection, ensuring accurate exposure evaluation.

1,3-Butadiene is best sampled with sorbent tubes such as Tenax TA, following NIOSH Method 1501, at a flow rate of 0.2 L/min over the entire task duration (15-30 minutes) to capture peak exposures during cleaning activities. Laboratory analysis using thermal desorption coupled with GC-MS ensures specificity and sensitivity for 1,3-butadiene detection.

Sampling calibration involves pre- and post-sampling pump calibration using a primary standard such as a bubble calibrator or a soap bubble flowmeter, ensuring flow rates remain within ±5%. The choice of sampling media and analytical method depends on chemical volatility, expected concentration levels, and detection limits, aligning with OSHA/NIOSH standards to produce reliable and reproducible results.

Part 3: Analysis of Sampling Results and Comparison to OSHA PELs

Based on the sampled data, the following calculations determine the 8-hour TWA exposures:

  • Mineral oil mist: For two samples, 1.1 mg/m3 and 0.9 mg/m3, both below OSHA’s PEL of 5 mg/m3, indicating no overexposure.
  • Hexavalent chromium: Exposures of 8.5 µg/m3 and 10.0 µg/m3 exceed OSHA’s PEL of 5 µg/m3, thereby representing significant overexposure risks requiring controls.
  • Xylene: 24 ppm is below the OSHA PEL of 100 ppm, so no concern here.
  • MEK: 60 ppm is below the OSHA PEL of 250 ppm, safe under current exposure levels.
  • 1,3-Butadiene: 6.0 ppm exceeds OSHA’s PEL of 1 ppm, indicating a need for exposure mitigation.

The noise exposure results, with levels ranging from 80.0 dBA to 100 dBA, surpass OSHA’s permissible limit of 90 dBA for several workers, notably those operating the 2,000-ton press and during cleanup procedures, indicating a need for noise control measures.

Summary and Recommendations

The sampling data reveal that welders’ inhalation exposure to hexavalent chromium and certain cleaning employees’ exposure to 1,3-butadiene exceed permissible limits, necessitating immediate intervention. None of the solvent exposures currently surpass OSHA limits, but regular monitoring is recommended due to their volatility. Noise levels during certain operations exceed safe thresholds, which can damage hearing over time if unaddressed.

References

  • Occupational Safety and Health Administration (OSHA). (2023). OSHA standards for chemicals and noise. https://www.osha.gov
  • National Institute for Occupational Safety and Health (NIOSH). (2023). NIOSH Manual of Analytical Methods (NMAM). https://www.cdc.gov/niosh/nmam
  • American Conference of Governmental Industrial Hygienists (ACGIH). (2023). TLVs and BEIs. Cincinnati, OH: ACGIH.
  • Leffingwell, J. C. (2019). Occupational hygiene practices for chemical exposure assessment. Journal of Occupational Health, 61(4), 341-351.
  • Cascio, W. F., & Shen, C. (2020). Noise and hearing loss in industrial environments. Industrial Health, 58(3), 157-164.
  • McKinnon, P., & Lin, F. (2021). Chemical exposure controls in manufacturing settings. Journal of Occupational Safety, 63(2), 213-224.
  • Nelson, D. I., & Kohn, N. (2022). Techniques in environmental monitoring: Chemical sampling methods. Environmental Monitoring and Assessment, 194, 15.
  • Gibson, J., & Smith, T. (2020). Personal protective equipment and engineering controls for chemical hazards. Safety Science, 124, 104593.
  • Chung, K., & Lee, S. (2018). Evaluation of noise and chemical hazards in manufacturing plants. Applied Occupational and Environmental Hygiene, 33(6), 337-347.
  • Harrington, D. P., & Campbell, C. (2023). Advances in workplace exposure assessment methodologies. Journal of Safety Research, 86, 102378.

Related Assignments