Implementing task-based exposure assessment for noise.
Waters-M; Brueck-S; Prince-M; Stancescu-D; Woskie-S
American Industrial Hygiene Conference and Exposition, May 21-26, 2005, Anaheim, California. Fairfax, VA: American Industrial Hygiene Association, 2005 May; :31-32
More than 30 million US workers are exposed to TWA noise levels >85 dB, a level associated with significant hearing loss risk. The 8-hour TWA using dosimetry is the most common noise metric, but does not capture task level characteristics (e.g. high exposure tasks) nor the complexities of time-varying or impulsive noise exposures. Task-based (TB) strategies permit high-noise task identification, targeting of controls, and fuller noise characterization for development of damage-risk models that incorporate time-varying and impulsive noise aspects. Implementation of a TB strategy is described. NIOSH studied 364 workers at three manufacturing plants (60-85% workers exposed to >85 dB.). One study aim was to examine measurement variability in daily noise TWAs by conducting simultaneous dosimetry and TB sampling with three repeated measures per worker. Department and job lists, layouts, job descriptions, and historical noise data were obtained from each plant. Jobs were selected based on homogeneity of tasks, higher noise exposures, impulsive noise exposures, and >= 5 workers per group. Observation and interviews of workers and supervisors were used to develop task lists. Dosimetry and TB samples were collected simultaneously with direct observation and task-tracking for the entire shift. Time-at-task was measured and also estimated using three methods. Standardized task-lists were developed for 26 job groups, with five to 23 tasks per job. Work-sampling analysis showed 15-minute sampling intervals were sufficient for analyzed tasks. Of 364 workers, 229 were directly observed during measurement (dosimetry and TB) and 135 had only dosimetry. Variability of time-at-task estimates depended on estimation method. Clear task definition is crucial to the success of a TB approach, yet workers, supervisors, and researchers defined tasks differently. Although a TB strategy improves the validity of the exposure assessment and guides control efforts, cost and personnel time are not insignificant relative to other approaches.
Exposure-assessment; Noise; Noise-exposure; Workers; Occupational-exposure; Noise-levels; Noise-induced-hearing-loss; Hearing-loss; Risk-factors; Risk-analysis; Dosimetry; Models; Workplace-studies
Disease and Injury: Hearing Loss
American Industrial Hygiene Conference and Exposition, May 21-26, 2005, Anaheim, California