[Correlation between work conditions and the occurrence of vibration disease in forestry workers II].

The frequency of occurrence of vibration disease in 460 randomly chosen sawworkers, from 20 to 65 years of age, working with motor-saws of the KBK-3a and Partner R-11 types was determined. The control group consisted of 136 forestry workers non-exposed to vibration. Vibration disease was observed in 22.6% of motor-sawers, and it was suspected in 6.7%. The occurrence of vibration disease is significantly dependent on the age, daily exposure to vibration, working period in years and--especially strongly--(p less than 0.001) on the amount of timber produced and fuel used for the saw. It was discovered that daily exposure to motor-saw vibration with the type BK-3a considered, should not exceed 2 hours a day. The amount of timber produced by the saw-worker as m3 of timber felled, should not exceed 5.000 m3 in a year and 40.000 m3 in the whole employment period.