Prevalence of pneumoconiosis among workers processing pelelith

Objective To understand the prevalence of pneumoconiosis among persons processing pelelith,and analyzing the relationship between pneumoconiosis and experience of pelelith processing, so as to provide the scientific evidence to make the specific policies for prevention and control pneumoconiosis. Methods A hygiene survey among all of units which had registered in Industrial and Commercial Bureau was conducted,physical examination was performed among persons who were exposed to the dust of pelelith,and at the same time,the concentration of dust of pelelith and free silica was tested. Results A total of 958 workers from 228 plants registered in Industrial and Commercial Bureau were recruited. The content of free silica ranged 1.14%-7.67%. The pelelith dust concentration varied from 0.01 mg/m³ to 3.10 mg/m³ in the pelelith cutting sites and the average was 0.80 mg/m³. 857 workers(male 734 and female 123) in 209 registered plants received the physical examination,accounting for 89.5% of total workers. The age of these workers varied from 16 to 74 years old and the mean age was 37.8 years. The time of processing pelelith varied from 7 days to 31 years and the average was 4.46 years. Two cases of pneumoconiosis with I stage were identified and the prevalence rate was 0.23%(2/857). Conclusion Long-term exposure to pelelith dust may result in pneumoconiosis,and thus,there is a need to strengthen the prevention and control pneumoconiosis among workers processing pelelith.