Information on nineteen metals in atmospheric deposition potentially toxic to humans and other organisms was evaluated to conclude if metal concentrations are increasing in atmospheric deposition and if these concentrations threaten human or organism health. On the basis of rates of emission, atmospheric concentrations, and known temporal trends, in deposition, Ag, Cd, Cu, Pb, Sb, Se, and Zn can be expected to show the greatest increases due to human activity with little or no increases expected for Co, Mn, Ni, and Tl. The limited data available supported these expectations. In some cases, dry fallout was found to be significant relative to wet deposition. Of the metals studied only As, Hg, Se and possible Cd are in the vapor phase in the atmosphere. Relative to the impact of these increased concentrations, Hg and Pb are now being deposited in some areas at levels toxic to humans and Cd, Cu, Hg, Pb, and Zn at levels toxic to other organisms. (Copyright (c) 1982 Pergamon Press Ltd.)