The Department of Energy maintains a significant inventory of radioactive substances at facilities throughout the United States. To help ensure the safety of its workforce, the Department established a two-tiered approach to biological or "bioassay" testing of workers to determine whether and to what extent they may have absorbed radioactive material. The more intense process mandates biological testing and applies to the relatively few workers with significant exposure risk. When significant exposures are not expected - the situation at most sites and upon which this audit focused - the Department's contractors are required to develop a program to ensure that controls are effective in reducing exposures to radioactive substances. Specific components of the program are left to the discretion of the contractor. However, most rely on continuous air monitoring, radiological surveys, and confimlatory bioassay testing. Prior Office of Inspector General reviews have identified problems regarding the cost effectiveness and efficiency of the Department's bioassay monitoring program. Given the current emphasis on worker safety and the obvious dangers posed by excessive radiation exposure, we initiated this audit to determine whether contractor-developed bioassay programs were effectively administered.