As part of PCA's on-call Certified Industrial Hygienist (CIH) contract with the New York City Department of Environmental Protection (NYCDEP) Bureau of Water Supply (BWS), PCA, in conjunction with Novisal, was requested to perform full-shift noise dosimetry at the Croton Filtration Plant (CFP). The purpose of the measurement study was to determine compliance with Occupational Safety and Health Administration (OSHA) occupational noise exposure standards, codified at 23 CFR 1910 Subpart G - Occupational Health and Environmental Control and NYCDEP's Hearing Conservation Environmental Health & Safety Policies, Procedures and Guidelines, dated October 27, 2003. In addition, data could be used to assist in defining which job classifications, if any, are to be included in the Hearing Conservation Program for BWS.
Based on review of information provided by NYCDEP, noise exposure levels were evaluated for seventeen (17) personnel over the twelve (12) job categories. These job categories included Water Shed Maintainer (WSM) and Water Shed Maintainer Supervisor (SWSM), Environmental Health and Safety (EHS), Laboratory, and Bureau IT personnel as well as Instrumentation Specialist, Instrumentation Specialist supervisor, Stationary Electric Engineer (SEE), Engineer, Plumber, Machinist, and Electrician. PCA/Novisal personnel fitted each participant with a dosimeter prior to the beginning of their work shift. Participants were requested to log their activities on field sheets provided by PCA/Novisal. To supplement each participant’s notes, PCA/Novisal reviewed timecards and available work orders provided by NYCDEP. PCA/Novisal also conducted area sound level measurements during an approximate 30-minute exercise period of a 2-megawatt emergency generator during routine testing.
The findings of the study indicated that all job classifications with one exception measured below the Occupational Health and Safety Administration’s (OSHA) Action Level (AL) for noise of 85 dBA for an 8-hour shift. Based on these findings, PCA/Novisal recommended that consideration be given to perform additional measurements or modify the sampling design to reduce the width of the confidence interval using Type 1 meters to obtain a more conclusive result for the EHS Operations job category. Data from all other job categories monitored were well-below the OSHA AL and, as a result, did not meet the requirements for inclusion in the site Hearing Conservation Program. Since the measurements represented one day of work activities, which can vary based on preventative and emergency maintenance requirements, PCA/Novisal recommended the study data be compared with prior study data or supplemented with a second day of measurements when considering job classification assignments in the site Hearing Conservation Program. A Noise Dosimetry Findings Report was prepared and submitted to NYCDEP for review and acceptance.