Aluminum smelter workers [56] with 10-43 yr occupational exposure, and who had been previously studied medically, were re-X-rayed. Average urinary fluoride concentrations since 1960 were estimated to range from 2.78 mg/l preshift and 7.71 mg/l postshift. Roentgenographic studies in 1960-66 and 1974 failed to reveal any evidence of fluoride associated bony change. Although these workers represent a self-selected group, their magnitude and duration of exposure far outweighs any other group working at present or in the past at this plant. The implication that they have uniformly self-selected as fluoride resistant individuals is improbable. Group post-shift urinary fluoride concentrations averaging less than 8 mg/l over a long period probably is not associated with enhanced risk of bony fluorosis. If preshift urinary fluoride concentrations are < 4 mg/l, the same result appears to apply.