The annual changes of vibration hazards in the lumberjacks of state forests

Abstract

Since 1958, with the labor rationalization policy of the state forests, chain-saws have been widely introduced in the felling operation of trees. Chain-saws have often caused damage to-operators as have other vibrating tools such as drills, hammers and grinders. It was negotiated between labor and management in 1969 that one can not operate the chain-saw more than 2 hr per day for the prevention of hazards, furthermore, that persons with vibration hazards, particularly white waxy hands, should not continue to use the chain-saw and to receive medical treatment with the recognition of the hazards as prescribed occupational hazards and with the displacement of their occupations. Medical examinations were carried out on the lumberjacks of the State Forests in Yamaguchi Prefecture for 6 years since 1970. In the present study, the effects of the time regulation of the use of chain-saw on the symptoms and the progress of the symptoms of serious cases after discontinuing the use of chain-saw were investigated. It was found that the regulation of operation time scarcely affected the symptoms. Peripheral blood circulation and peripheral nerve sensation were still impaired with the use of chain-saw. The complaints of the finger numbness and of the systemic indisposition had increased each year. On the other hand, the progress of the symptoms after discontinuing the use of chain-saw resulted in a tendency of a decrease of the Raynaud's phenomenon and recovery of the peripheral blood circulation and the peripheral nerve sensation, whereas the finger numbness still continued. Therefore it is necessary to find out a more satisfactory measure in the medical treatment of these hazards. Now every lumberjack has given up the use of chain-saw and has started to use an ax and a saw again. There are used freely by persons with vibration hazards as well as by the others. We are worried about the effects of ax impacts and vibrations and of strained posture leading to cervicobrachical syndrome and of low back pain. It seems to be necessary to consider preventive measures against these injuries. © 1977, Japan Society for Occupational Health. All rights reserved.