Summary: After pursuing for a decade a strategy for underground tests with nuclear wastes in the Waste Isolation Pilot Plant--a proposed repository for the disposal of transuranic wastes located near Carlsbad, New Mexico--the Energy Department (DOE) announced in October 1993 that it was abandoning these tests in favor of laboratory-based tests. DOE claimed that this change would save about $139 million by January 2000 and would allow DOE to begin disposing of waste by 1998. The general consensus among scientists, experts, and regulators is that DOE's decision to discontinue its planned underground tests with transuranic wastes is sound. However, GAO questions DOE's projected cost savings. For instance, DOE lacks documentation for many elements of the estimated cost savings. GAO also concludes that DOE will not be able to open the plant by 1998 instead of 2000. Numerous unresolved issues could affect when DOE can eventually begin disposing of wastes in the facility. For example it is unclear whether DOE's schedule gives the Environmental Protection Agency enough time to review DOE's procedures and decide if DOE has complied with EPA's regulatory requirements for disposing of transuranic wastes in a repository.