In 1977 a Finnish foundry implemented the use of newwheels of zirconium corundum for pedestal grinding. Within a year the workers developed vibration-induced white finger (VWF). Ten were studied electroneuromyographically in 1979,and again in 1980 and 1983 after the zirconium corundum had been replaced by normal corundum. In 1979the mean distal sensory conduction velocity (dSCV) of the median nerve was below the lower normal limit, and that of the ulnar nervewas close to the normal limit. Only two workers had a normal dSCVof the median nerve bilaterally, whereas four had a normal ulnar nerve value bilaterally. The results had improved slightly in 1980and 1983, the mean values being within normal limits with some individual values still abnormal. Subjective symptoms were still frequent in 1983,the same nine workers still complaining of paresthesias in the hands and fingersand five reporting hand-arm pain. All still had VWFattacks, at least occasionally. The higher impulsiveness of the vibration from the zirconium corundum wheels, together with highfrequency components of vibration, was considered to be the major cause of the quick development of the sensory nerve damage that was found in 1979.