Abstract The effect of chromium from cooling tower drift on vegetation was assessed at the Oak Ridge Gaseous Diffusion Plant using Kentucky Burley 21 tobacco plants ( Nicotiana tabacum) which is noted for its sensitivity to chromium. Potted tobacco plants were placed along the axis of the most frequent wind direction at 15, 200, 600. and 1400 m from the cooling towers. Plants were harvested at one-week intervals for seven weeks from each distance and assessed for total plant biomas. leaf biomass. leaf area, general vigor determinations and chromium concentrations. There was an inverse relationship between foliar chromium concentrations and distance from the towers. Associated with high chromium concentration was a 75 per cent inhibition of leaf growth.