The U.S. Department of Energy (DOE) disposes of plutonium-contaminated debris from its 27 nuclear weapons facilities at the Waste Isolation Pilot Plant (WIPP), an underground repository in Carlsbad, New Mexico. After four years of operational experience, DOE has opportunities to make changes to the costly and time-consuming process of "characterizing" the waste to confirm that it is appropriate for shipment to and disposal at WIPP. The report says that in order to make such changes, DOE should conduct and publish a systematic and quantitative assessment to show that the proposed changes would not affect the protection of workers, the public, or the environment.