Objective: This descriptive study was aimed at investigating: 1) the occupational noise exposure levels, 2) the prevalence of noise-induced hearing loss (NIHL) in 2001 compared to a previous study in 1998 and 3) the achievement of existing hearing conservation programs in Songklanagarind Hospital.

Design: Descriptive study

Material and methods: The study subjects included 108 workers from 3 departments in Songklanagarind Hospital (central supply, food supply and maintenance departments) from November 2001 to April 2002. A walk-through survey and noise level assessment using a sound level meter and noise dosimeter were carried out on a sample of 63 employees for 8-hr time weighted average (TWA) continuous noise and 35 employees for impulse noise. All employees who had undergone audiometric testing in 1998 were interveiwed and given an audiogram by the hospital audiologist.

Results: The percentage of employees exposed to noise levels exceeding 85 dB(A) in 2001 was 52% in the food supply department and 25% in the maintenance department; and the percentage of impulse noise beyond 140 dB(peak) was 40.9% in the food supply department and 46.2% in the maintenance department. No noise exposure and impulse noise level exceeded the standard limits in the central supply department. The prevalence of NIHL was 35.2%, which could be classified as registered hearing loss (RHL) 32.4% and NIHL 2.7%. In comparision with a previous study in 1998, there were 7 new cases of RHL or a 6.5% increase in 2001. The result also reflected the unsatisfactory efficacy of the hearing conservation program both at policy and operation level such as: no policy declaration, inadequate hearing protection devices provided on a regular basis throughout the year and irregular hearing tests for the risk groups.

Conclusions: A large percentage of employees having 8-hr TWA noise and impulse noise exposure over limited value and the increase of new hearing loss cases suggested that more effective hearing conservation program should be urgently launched.