UCH of the effort to reduce our vulnerability to cancer is directed toward an application of the regulatory process to the identification of persons at high risk and the reduction of their exposures to toxic substances for which there is evidence of carcinogenic potential. This process may be viewed as consisting of a number of essentially sequential steps: the gathering and evaluation of data on toxicity, on use, on human exposure and economic factors; the balancing of benefits-long-term and short-term-and costs, followed by implementation of the decision; and the control process. Despite the regulatory authority to accomplish these steps, progress has been slow in setting standards and in carrying out other activities to prevent the development of neoplasms that would, at later stages, threaten life or health. Resources available to regulatory agencies are often limited compared to the magnitude of the problem, and the current ad hoc approach to the regulation of toxic agents will probably continue for the foreseeable future because of constraints in scientific knowledge, laboratory personnel, technical personnel, technical resources, and the complexity of socioeconomic, political, and legal factors to be considered. The scope of these issues is much too great to be reviewed in a single presentation. This paper shall, therefore, be illustrative rather than comprehensive in the topics addressed. TSCA IMPLEMENTATION