Investigation on health status of workers in a methanol production plant

Objective To understand the potential adverse effects of long-term exposure to methanol among occupational exposed population, and to provide the orientation for the occupation health management in the methanol production plant. Methods The monitoring data of occupational hazards, noise and methanol at workplaces were collected. The workers were divided into two groups, namely, 113 workers exposed to both methanol and noise and 101 workers exposed simply to noise. The results of health condition of these two workers were compared. Results The airborne concentration of methanol at different workplaces varied from 1.7 mg/m³ to 37.2 mg/m³, the exposure level (8 h time weighted average concentration) of workers varied from 0.9 mg/m³ to 18.3 mg/m³. The noise level (8 h equivalent sound level) varied from 57.5 to 86.3 dB (A)at these workplaces where the workers were exposed to both noise and methanol. At non-methanol production workplaces, the noise level varied from 56.9 to 89.2 dB (A). There was no statistically significant difference of the noise exposure level between these two groups(P>0.05). However, the workers exposed to both methanol and noise had higher prevalence of headache, blurred vision, dizziness, insomnia, eye pain, sore throat, skin itching, liver dysfunction and fatty liver, compared with those of the workers exposed simply to noise(P<0.05 or 0.01). Some of the workers exposed both to noise and methanol had rough skin on hand. Conclusion Long-term and low-level exposure to methanol could cause health damage of exposed workers. Compared with the reports by previous literatures, the health condition of these exposed workers in this plant was much better, which indicated the occupational health work in this plant was done well. However, more work should be done in the future to protect workers' health.