All 169 caulkers employed at a ship yard were examined to determine the prevalence of vibration syndrome due to pneumatic portable tools (chipping hammer and grinders). Vibration measurements and medical investigations were performed in the field between September 1977 and July 1978. Vibration spectra recorded on pneumatic tools were compared to ISO Draft Proposal No. 5369. The chipping hammer produced the highest acceleration levels and exceeded the maximum ISO limits even for a short exposure time (30 min per shift). The results of medical investigations pointed out that 78.7% of caulkers experienced paresthesia in their hands, 31.3% Raynaud's phenomenon (or VWF), 20.1% presented with radiological signs of osteoarthritis at wrist and shoulders, 10.0% with olecranon exostoses, and 31.3% with cysts of the carpal bones. To diagnose VWF the skin temperature of the hands were recorded in all 169 caulkers and 60 controls at the shipyard. The basal skin thermometric map (recorded in 16 positions per hand) demonstrated an average difference of 2-2.5 degrees C between the two populations. The thermometric curve, monitored every 3 min for 40 min after a provocative cold-test (immersion of hands and wrists in melting ice for 2 min), well differentiated workers exposed and not exposed to vibrations. The authors emphasize that skin temperature (before and after the cold-test) are suitable for epidemiological purposes to compare the prevalence rates of VWF in control-experimental groups.