BACKGROUNDNoise is widespread occupational hazard in iron and steel industry. Overhead-traveling cranes are widely used in this industry, but few studies characterized the overhead-traveling crane drivers' noise exposure level so far. In this study, we assessed and characterized personal noise exposure levels of overhead-traveling crane drivers in two steel-rolling mills.

METHODSOne hundred and twenty-four overhead-traveling crane drivers, 76 in the cold steel-rolling mill and 48 in the hot steel-rolling mill, were enrolled in the study. Personal noise dosimeters (AIHUA Instruments Model AWA5610e, Hangzhou, China) were used to collect full-shift noise exposure data from all the participants. Crane drivers carried dosimeters with microphones placed near their collars during the work shifts. Work logs had been taken by the drivers simultaneously. Personal noise exposure data were divided into segments based on lines in which they worked. All statistical analyses were done using SPSS 13.0.

RESULTSThe average personal noise exposure (L(Aeq.8h)) of overhead-traveling crane drivers in the hot steel-rolling mills ((85.03 +/- 2.25) dB (A)) was higher than that in the cold one ((83.05 +/- 2.93) dB (A), P < 0.001). There were 17 overhead traveling cranes in the hot steel-rolling mill and 24 cranes in the cold one, of which carrying capacities varied from 15 tons to 100 tons. The average noise exposure level based on different lines in the hot and cold steel-rolling mills were (85.2 +/- 2.61) dB (A) and (83.3 +/- 3.10) dB (A) respectively (P = 0.001), which were similar to the average personal noise exposure in both mills. The noise exposure levels were different among different lines (P = 0.021).

CONCLUSIONNoise exposure levels, depending upon background noise levels and the noise levels on the ground, are inconstant. As the noise exposure levels are above the 85 dB (A) criteria, these drivers should be involved in the Hearing Conservation Program to protect their hearing.