Introduction A textile company in Indonesia has began to have a well organise Hearing Conservation Program after 30 years of production. With the level of noise around 85 dB – 104 dB in workplace without having baseline data, it was a challenge to investigate of occupational NIHL. On the other hand measuring Standard threshold shifts (STS) could help in determining the impact of noise at least for 1 year. Most studies about NIHL use cross sectional method and the prevalence is more than 30%.

Aim This study aimed to investigate of occupational NIHL by combining the type of hearing loss and STS results in 1 year.

Methods Prospective audiometric study performed in 487 male workers who have been worked for more than 3 years. Audiometric STS using OSHA standard. Defining as occupational NIHL if the STS was positive and the type of hearing loss were sensory neural hearing loss or mix hearing loss.

Results There were 147 (30%) workers who have hearing loss consist of 52 (10.7%) mix hearing loss, 74 (15.2%) conductive hearing loss and 21 (4.3) sensory neural hearing loss. Workers with STS (+) were 32 (7%) consist of 17 (3.4%) mix hearing loss, 1 (0.2%) conductive hearing loss, 10 (2%) sensory neural hearing loss and 4 (0.8%) normal hearing. Base on the combination of STS (+) and mix and sensory neural hearing los, the occupational NIHL loss was 27 (5.5%). Risk factors that have significant risk was age.

Conclution The prevalence of hearing loss is high but the type of hearing loss was mostly conductive hearing loss and this type of hearing loss is not caused by noise. The prevalence of occupational NIHL was 5.5%. Its needed to investigate the cause of conductive hearing loss because mostly the NIHL were mix hearing loss.