This manuscript explores the risks associated with exposure to carcinogenic chemicals that have become a growing source of public concern. Steadily increasing numbers of agents are being identified as mutagens and carcinogens. Furthermore, we are increasingly aware of sources of exposure to such agents both in the occupational setting and general environment. There is a growing need for reliable and sensitive methods for detecting human exposure to carcinogenic hazards at the time of their occurrence. By detecting hazards early, significant reduction in the risk of adverse health outcome can be achieved by reduction or termination of exposure. The monitoring of human populations for genetic damage has the potential to improve our ability to detect health hazards and prevent or reduce the risk of workplace-exposure-related cancer. In the long run this can reduce costs related to illness. It is possible that the costs of exposure control can also be reduced by better establishing the sources of significant exposure and by understanding the human response to exposure. However, its greatest promise is in the protection of human health through the early detection and prevention of disease processes resulting from mutagenic exposure.