All 607 men, aged 17 to 69, comprising a stratified sample of workers from one shipyard completed a respiratory questionnaire, clinical examination, and detailed spirometry. Chest radiographs were available on 332 men. Among the men aged 50-69 the prevalence of persistent cough and phlegm (chronic bronchitis) was 40%, of wheeze on most days 25%, and undue breathlessness on exertion 25%. After allowing for age the relative risk of welders and caulker/ burners having these symptoms were respectively 2-8, 2-2, and 3-1 compared with other shipyard tradesmen. The effects were of comparable magnitude to and interacted with those of current smoking. Among the welders and caulker/burners who smoked, the relative risk of developing chronic bronchitis or undue breathlessness was related to the average fume exposure; the relative risk of wheeze was related to the average fume exposure in all smoking categories, with the strongest association in the ex-smokers. The occurrence of wheeze was also associated with a history of previous metal fume fever. A history of pleurisy but not of pneumonia was related to the fume exposure in.the welders. After allowing for age and stature, forced expiratory volume (FEV,) was on average higher in young welders (age < 30) than other tradesmen. In welders and caulker/burners who were current or ex-smokers, FEV, and PEF were reduced in relation to the average fume exposure (mean reductions respectively 0 25 1 and 0 99 1 s-'). The FEV,% (of forced vital capacity), the flow rates at small lung volumes (MEF50%Fvc and MEF25%FVc), the mean transit time, and its standard deviation were also reduced by fume exposure or the declines with age were increased, or both. No impairment was demonstrable in the non-smokers and many men had given up smoking with apparently beneficial results. The occupational component ofthe respiratory impairment related mainly to exposures in the past; information was needed on the effects of present conditions in the industry.In NE England ships are made from mild steel. The sheets are joined by welders who normally use flux covered electrodes (manual metal arc welding). Burners, whose trade is linked to that ofcaulkers, buff and burn offany metal protruding from the completed welds; they also gouge and cut the welded plates. Both groups of tradesmen are exposed to fumes from the weld metal (iron with an admixture of other substances), flux, coating materials, and solvents; the men may also inhale carbon monoxide, nitrogen dioxide, *Dr Feinmann died on 25 July 1983.Present address: CACW:
