The distribution of blood concentrations of lead (Pb), cadmium (Cd), chromium (Cr) and manganese (Mn) in residents of the German Ruhr area and its potential association with occupational exposure in metal industry and/or other risk factors.

•Metal workers had more frequently increased blood Pb and Mn concentrations.•Smoking hindered evaluating the influence of occupational exposure on Cd in blood.•Women had higher blood Mn and Pb concentrations than men.•95th percentiles of blood Cr, Ni, Cd, Mn and Pb were not significantly influenced by metal-related occupations.