Evaluation of noise levels and Hearing Test of Workers at a Stone Milling Factory in Surat Thani Province

Abstract

Noise-induced hearing loss (NIHL) was a condition of sensor neural hearing loss caused by prolonged loud noise exposure. The workers were a risk for hearing loss. This research aims to study the evaluation of the noise levels, the hearing ability test of workers and correlation between noise exposure of department and hearing loss among workers at a Stone Milling Factory. This study was cross-sectional descriptive design. Sample consisted of 34 employees: consisting of the quarrying department, the crushed stone department, the Sandstone Screening department, the maintenance department and the office department. The study was carried out between December 2024-March 2025. Noise level samples were collected using noise dosimeter and hearing ability test was tested using an audiometer. The results of the study found that the average noise expose level over an 8-hour time weighted average (TWA) exceeding the standard value of 85 dB(A) were the crushing department (90.7 dB(A)) followed by the sandstone screening department (85.6 dB(A)) and the quarry department (85.4 dB(A)). The results of the employee hearing assessment showed that maintenance department had the highest average hearing levels, followed by worker in the stone crushing department. The correlation between noise exposure of department was significantly associated with normal hearing (p-value < 0.001). However, all employees were found to have a normal hearing function. The establishment has implemented noise control measures at the source, conducted annual health check-ups for employees in high-risk areas to monitor potential hearing loss, and provided adequate and appropriate hearing protection equipment for each department's operations.