Although the Waste Isolation Pilot Plant (WIPP) in New Mexico is still shuttered from a radiation leak in February 2014, the Department of Energy is considering a recommendation to bury 34 metric tons of plutonium from dismantled nuclear weapons there. But a top U.S. nuclear scientist and policy expert and his colleagues areurging DOE to reconsider (Nature 2016, DOI: 10.1038/529149a). Rodney C. Ewing of Stanford University and collaborators question the safety record of WIPP and suggest that DOE consider “how difficult it is to predict potential failures of such a disposal system over millennia” before moving forward with disposal at the facility. An agreement between the U.S. and Russia calls for each country to dispose of excess weapons-grade plutonium from their respective nuclear weapon programs. Until last year, DOE was expected to move forward with a plan to convert the plutonium into mixed oxide fuel that can be used in reactors. But a task force commissioned by Energy Secretary Ernest Moniz in June 2015 recommended disposal at WIPP as a cost-saving alternative.