The metals of environmental, biological or commercial importance were studied in order to nominate chemicals as candidates for carcinogen bioassay to the National Cancer Institute. After the application of several qualifying criteria that related to previous, current or planned carcinogenicity tests, and to commercial significance, the preliminary candidate list of 1,383 chemicals was reduced to a final candidate list of 488 chemicals. Based upon consideration of both the suspicion of possible carcinogenic activity and evidence of potential human forty‐six chemicals were nominated.