[Occupational risks in the maintenance of pot-lining and anode firing furnaces]

A group of 66 pot-lining and anode furnace maintenance workers was examined, including 44 workers who had been exposed to these occupational hazards for more than one year. No occupational bronchial diseases were observed. Two cases of 1/0 grade silicosis and two cases of initial palmar aponeurosis retraction were reported. Seventeen cases (38.6%) of occupational hearing loss had been compensated or reported. Hearing loss exceeding the 2nd degree of the Merluzzi scale was observed in 11 workers. There were 13 cases of hearing loss (29.5%) according to ISO criteria, due to exposure levels calculated at 95/100 dB-A eq. Spirometry revealed only one worker with marked reduction in vital capacity. Urinary fluoride concentrations (1.37, S.D. = 0.63 pre-shift and 2.32, S.D. = 1.15 post shift) did not indicate any particular level of hazard. ECGs showed no significant alterations. Variance analysis and multiple regression techniques were used to study the relationship between respiratory volume, hearing capacity, age, duration of exposure and length of past exposure in the construction industry. A marked association was observed between age and hearing loss and a weaker association between duration of exposure and hearing loss.