Noise Exposure in Electric and Natural Gas Utility Transmission and Distribution Operations

Christi Cole, Montana Tech of the University of Montana


Noise exposures were measured in the electric and natural gas distribution operations workforce of a large Midwestern utility. Both personal dosimetry and area monitoring were utilized to evaluate noise exposures based on job classification as well as operation of specific equipment or performance of certain tasks. Job classifications were chosen for study based on observable noise exposures and employee requests. Five job classifications were sampled with 90% confidence according to NIOSH guidelines for sample sizes. Three of the five job classifications were previously enrolled in the company hearing conservation program and two of them were not.

The study determined that four of the five work groups met the exposure criteria for inclusion in an employer sponsored hearing conservation program while the fifth group did not. The group that did not demonstrate exposures above the inclusion criterion should not be excluded from the program as it was revealed that other exposures exist that were not able to be measured during the study. These activities need to be evaluated before the group can be removed from the hearing conservation program. All three of the task based analysis studies demonstrated noise exposure or the potential for noise exposure higher than regulatory limits. As a result of the measurements, double hearing protection was recommended for one task and the final task based analysis revealed potential for exposure so high that engineering controls or remote operation methods must be pursued.