Analysis on occupational health status of noise exposure workers in a steel pipe manufacturing enterprise in Tianjin

Background Productive noise, as one of the common occupational hazards, has a particularly prominent impact on the health of occupational populations in China. Noise pollution is widespread in the steel pipe manufacturing industry, and the health of noise-exposed workers is worthy of attention.

Objective The study investigates noise levels of a steel pipe manufacturing enterprise in Tianjin and health status of the noise-exposed workers, and provides evidence for the enterprise to carry out occupational health protection work.

Methods The monitoring results of occupational hazard factors of the enterprise and the occupational health examination data of 2 333 noise-exposed workers in 2019 were retrieved, and the levels and distributions of occupational hazard factors in the workplace were analyzed. According to pure-tone hearing test results, the workers with a high-frequency hearing threshold ≥ 40 dB in any frequency of 3, 4, and 6 kHz were included in the highfrequency hearing loss group, and the workers with a high-frequency hearing threshold < 40 dB were included in the normal hearing group. The differences in electrocardiogram (ECG), liver function, blood pressure, blood lipid, and blood glucose between the two groups were analyzed by t-test and chi-square test.

Results Among the 2 333 noise-exposed workers, there were 2 327 males and 6 females. The average age was (37.16±6.34) years, and the average noise exposure working age was (10.96±5.57) years. The reported workplace sound pressure level was 80.0-102.5 dB(A), 227 out of the 393 noise-exposed workplaces (57.76%) were noise-only workplaces, and the remaining workplaces were additionally exposed to physical factors (high temperature) or chemicals (such as hydrogen sulfide, dust, and organic solvents). The noise levels of 128 workplaces (32.57%) and the dust concentrations of 5 workplaces exceeded the corresponding occupational exposure limits, and the test results of other hazard factors met the requirements of relevant occupational exposure limits. The detection rate of highfrequency hearing loss in the 2 333 workers was 38.45%, and increased with age and years of noise exposure (χ²_trend=222.48, 31.13, P < 0.01). The detection rates of high total cholesterol (35.90%) and high triglycerides (45.04%) and the prevalence rate of fatty liver (65.89%) in the high-frequency hearing loss group were higher than those in the normal hearing group (P < 0.05). In addition, the detection rates of hyperglycemia (11.82%) and hypertension (17.06%) and the abnormal rate of ECG (18.06%) in the high-frequency hearing loss group were also higher than those in the normal hearing group (P < 0.05). The abnormal types of ECG in the high-frequency hearing loss group were mainly ST-T changes and sinus bradycardia, and the detection rates of both types were higher than those in the normal hearing group (P < 0.05).

Conclusion Noise pollution is widespread in the selected steel pipe manufacturing enterprise and may have remarkable impacts on the auditory and non-auditory system health of noise-exposed workers.