On November 8, 2004, the National Institute for Occupational Safety and Health (NIOSH) received a request for a health hazard evaluation from the Safety Manager for Kentucky Sanitation District #1 (SD#1) asking for assistance in evaluating the department's Hearing Conservation Program (HCP), employees' daily noise exposures, and sound levels of noise sources. The Sanitation District has 160 employees who maintain and install sewer lines. Workers also operate the Dry Creek Sewage Treatment plant and several small sewage treatment plants and pump stations. Because employees are potentially exposed to noise from pumps, compressors, vacuum trucks used to clear sewer lines, and construction equipment used to maintain and install sewer lines, all employees are included in the SD#1 HCP. During November 2004 and February 2005 field surveys, NIOSH personnel measured noise levels, conducted noise dosimetry on personnel working around noise sources, and reviewed audiometric records, the OSHA 300 Log of Work-Related Injury and Illnesses, and a draft of the SD#1 written HCP guidelines. Noise sources within the SD#1 ranged from 70-98 dBA. Noise dosimetry results for a vactor truck operator and his assistant exceeded the OSHA Action Level (AL) of 85 dBA as an 8-hour time- weighted average (TWA). Noise dosimetry results for a treatment plant operator, maintenance worker, trackhoe operator and his assistant were above the NIOSH REL. The review of the HCP found no records of previous noise surveys or of noise dosimetry and hearing protection use was optional. Warning signs posted in high noise areas provided time limits for remaining in these areas without hearing protection

however, SD#1 had no noise measurements to support the time limits. Sound level measurements taken by NIOSH investigators in these areas indicated that the time limits did not meet OSHA criteria for noise exposure. NIOSH investigators conclude that a potential noise hazard exists for SD#1 vactor truck operators, vactor truck assistants, treatment plant operators, maintenance workers, and trackhoe operators. Recommendations are provided to revise the SD#1 written HCP and the noise area warning signs. The recommendations will improve the HCP by ensuring that employees with standard threshold shifts (STSs) receive adequate follow-up and that STSs that meet the OSHA criteria for recordability are recorded on the OSHA 300 Log of Work-Related Injuries and Illnesses.