Arc welders' respiratory health evolution over five years.

The respiratory health of 138 arc welders and 106 control subjects in the same company was studied in 1981 and in 1986. Most of the subjects welded mild steel using the Metal Inert Gas (MIG) process. The controls were workers in the same company, not exposed to any known pulmonary risk. The welders and controls in the analysis had not changed their professional activity nor their smoking habits during these five years. The examinations consisted of a questionnaire on respiratory symptoms, a thoracic auscultation, a chest X-ray and lung function tests: flow-volume curve and steady state CO transfer test. The examinations in 1986 confirmed the risk of non specific radiological impairment (pulmonary reticulo-micronodulation) and of obstruction in the small bronchi, which had already been observed in 1981 in the arc welders in this company. These impairments did not seem to have evolved more than in the controls, but do however justify regular surveillance of the respiratory health of arc welders.