Low Exposure to Asbestos

Abstract

In a previous survey of shipyard pipe coverers and controls, clinical criteria were used to define pulmonary asbestosis. This second survey focused on physiologic abnormalities. Pipe coverers had significantly reduced vital capacities (FVC) as well as single breath (DlSB) and exercise steady stale (DlSS-Ex) diffusing capacities. Resting steady state diffusing capacity (DlSS-R), fraction carbon monoxide removed (Fco), and the diffusing constant (K) differed from selected normals but not from all controls. Airways resistance, specific conductance, minute ventilation, arterial carbon dioxide pressure (Pco ₂) and dead space were not significantly abnormal. Obstructive disease was equally common in both groups. All workers with clinical “asbestosls” also had severely reduced Dl and Fco. The significance of isolated reduction of Dlrequires further study. However, In a third survey three years later, Dl in exposed workers had deteriorated more rapidly than FVC; some with initially isolated reduction of Dl had developed other signs of disease.