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Evaluation of employee exposures at a PCB plant.

Durgam S; Achutan C; Aristeguieta C; Niemeier MT
Print Circuit Design Fab/Circuits Assem 2011 Nov; 28(11):29-32
One of six personal breathing zone air samples for lead exceeded the Occupational Safety and Health Administration action limit (OSHA AL) of 30 micrograms per cubic meter (mu g/m3) and was close to the OSHA permissible exposure limit of 50 mu g/m3. This employee, a wave solder operator in the DAS, was cleaning the wave solder machines without wearing a respirator. The employee was exposed to an airborne lead concentration of 49 mu g/m3. However, with this one exception, wave solder operators had lead exposures well below the OSHA AL. Our surface sampling showed the presence of lead and tin on work surfaces in both sections of the plant. Currently, there are no OELs for surface metal contamination in occupational settings. We also sampled tables in two of the break rooms and found detectable levels of lead and tin in one of the break rooms. This suggests that workplace contamination is being tracked into the break rooms by employees' footwear, clothing or hands, and that these areas should be kept cleaner. Additionally, despite hand washing prior to sample collection, three of seven hand wipe samples tested positive for lead. Full-shift noise exposures for the AI operators in the medical and defense and aerospace section were well below the NIOSH recommended exposure limit. Because telephone communication is not required in the production areas, and communication between employees is minimal, the louder noise levels experienced by employees with work stations near the ARUs were within the criteria specified by the balanced noise criteria (NCB) 55-70 curves. The NCB curves are a set of noise criteria for occupied interior spaces, devised to limit noise to levels at which speech can be reasonably understood. Our ventilation evaluation revealed that several local exhaust hoods were not effectively capturing process emissions. These included three hoods in the medical section and two hoods in the defense and aerospace section. This could have been due to local exhaust ventilation systems being imbalanced or improperly maintained. Air sampling results for specific VOCs indicated that employee exposures were well below all applicable OELs. Although both the medical and defense and aerospace section share the main workspace and have similar tasks and equipment, the health concerns originated exclusively from employees in the medical section. Of the 40 medical section employees we interviewed, 23 did not report any work-related symptoms. The most commonly reported symptoms were upper respiratory, including runny nose, cough, and sinusitis; fatigue (frequently related to overtime work), and voice loss. However, these symptoms are also common in the general population, and we could not attribute them to the exposures documented. Last, we found inconsistencies between the facility's written respiratory protection program and employee practice. The written respiratory protection program required respirators to be worn when cleaning wave solder machines. However, it did not identify the appropriate type of respirator that should be worn for this task, and we did not observe employees wearing respirators when performing this activity. In addition, employees were voluntarily wearing respirators during spraying in the conformal coating area.
Breathing-zone; Health-standards; Noise-levels; Noise-measurement; Physiological-effects; Physiological-fatigue; Physiological-response; Physiological-testing; Respiratory-irritants; Respiratory-protection; Respiratory-protective-equipment; Sampling-methods; Soldering; Soldering-alloys; Surface-properties; Ventilation-equipment; Ventilation-systems; Work-environment; Worker-health; Workplace-studies
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Printed Circuit Design & Fab/Circuits Assembly
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division