Noise pollution and hearing loss in one of the oil industries in Iran

Introduction: Nowadays, noise exposure is one of the most important industrial
health problems. Noise exposure can cause hearing loss and many other health
problems. So, paying attention to the noise exposure problem should be of main
priority in industrial health programs. This study was conducted in an oil producing
region, aimed to assess noise pollution and noise induced hearing loss.
Methods: In this descriptive analytical study, study cases were working in a noise
producing industry. 55 workers randomly selected as a case group and 55 persons
who were working in the administrative department were selected as control group.
First, the noise producing source was defined and then sound levels were measured
by means of sound level definition and the hearing loss. Data analysis was by t-test
and correlation between noise hearing loss factors, using SPSS statistical software.
Results: Main noise sources were gas turbines, compressors, diesel generators,
fans and gas containing pipes. The results of noise level measurement show that
noise level at workplaces is higher than threshold limit value (P<0.001).
Analyzing the audiometric results show that in all frequencies hearing threshold
level of exposed workers is greater than hearing threshold of non exposed workers
and the workers exposed to noise levels more than 85dB have increased hearing
loss at high frequencies (P<0.001).
Conclusion: It can be concluded that oil industry is among the industries having a
hazard of hearing loss and other noise induced health disorders. In addition this study
shows inefficiency of noise control methods and hearing preservance programs in the
studied oil industry.