To investigate the current situation of noise exposure and hearing loss among the first-line workers in an oil field, compare the detection results before and after a comprehensive noise abatement program, and understand workers' occupational health surveillance situations.

Pure tone audiometry results of oil field workers from 13 oil production enterprises and 7 drilling enterprises from 2011 to 2014 were retrieved to perform statistical analysis. The on-site noise detection results were compared before and after the noise abatement program in the oil production enterprises in 2009 and 2010. One hundred workers were randomly selected from the oil production enterprises and drilling enterprises respectively to conduct a questionnaire survey on their awareness of hearing loss and protective equipment wearing rate.

The positive rates of oil production workers' hearing loss for the four years were 18.8%, 18.0%, 17.3%, and 16.4%, respectively (χ²=3.56, P>0.05); their medians of high frequency hearing threshold were 56.8-58.4 dB (H_c=0.98, P>0.05). The positive rates of drilling workers' hearing loss for the four years were 23.2%, 27.8, 23.2%, and 24.1%, respectively (χ²=3.98, P<0.05); their medians of high frequency hearing thresholds were 58.4, 60.3, 62.4, and 63.4 dB, respectively, with statistical differences (H_c=11.38, P<0.05). The oil production workers presented higher hearing loss awareness rates (80% vs 32%), protective equipment usage rates (87% vs 30%), and hearing protection documenting rates (59.6% vs 25.0%) than the drilling workers.

The first-line oil production workers show a stable and downward trend of hearing loss rate and loss degree. No differences in hearing loss rates are observed in the drilling workers with noise exposure, but the loss degree is increasing year by year.