AbstractSignificant concentrations of metals are found in the respirable particulate effluents associated with metallurgical smelters. In this investigation the effects of the metallic ions lead, cadmium, iron, mercury, aluminum, chromium, and nickel on various aspects of alveolar macrophage function were studied. The production of antibacterial substances (ie, reactive forms of oxygen) by these cells and oxygen consumption are very sensitive to the metals. Particle uptake displays moderate sensitivity, while lysosomal enzyme activity and membrane integrity are fairly resistant to metals. In addition, the effects of the organic solvents carbon tetrachloride, toluene, and xylene on alveolar macrophage function were tested. These solvents were found to inhibit oxygen consumption and the release of antibacterial substances while not greatly affecting membrane integrity. The results of these experiments indicate that some metals and some organic substances are toxic to alveolar macrophage function.