Nickel (Ni) and chromium (Cr) and some of its compounds may be able to induce cancer in the lungs as well as in the nose and paranasal sinuses after occupational exposure. Latency periods amount to 20 years and more. Therefore objective exposure data are not available in the most cases and expert evaluation of the causal connection is often difficult. Recent investigations have shown, that Ni and Cr can cumulate in human lung tissue after occupational exposure. For the evaluation of “normal” Ni- and Cr-values a total of 495 human lung tissue samples of 30 occupationally non-exposed persons were analysed by AAS including ZEEMAN-compensation after wet oxidative digestion. Additional samples of 10 deceased persons who have been occupationally exposed to nickel in previous times by nickel-refining and welding, especially flame spraying have been investigated. The median Ni- and Cr- concentrations in the lungs of the non-exposed persons ranged between 20–40 resp. 133–277 ng/g (wet weight). In nickel refinery workers Ni- concentrations were found which exceeded the normal range about 1,000. In welders, especially flame sprayers, also values more than 100 times higher could be analysed for Ni and Cr. Partially these concentrations were found years after the end of the inhalative exposure.