FILE - This file aerial photo, date not known, shows Los Alamos National Laboratory in Los Alamos, N.M. The U.S. government's efforts to clean up decades worth of Cold War-era waste from nuclear research and bomb making at federal sites around the country has chugged along, often at a pace that watchdogs and other critics say threatens public health and the environment. Now, fallout from the global coronavirus pandemic is resulting in more challenges as the nation's only underground repository for nuclear waste, the Waste Isolation Pilot Plant, finished ramping down operations Wednesday, April 1, 2020, to keep workers safe. (The Albuquerque Journal via AP, File)

FILE - In this file photo provided by the U.S. Department of Energy, cesium and strontium capsules are stored in water at the Department of Energy's Hanford site in Washington State. The U.S. government's efforts to clean up decades worth of Cold War-era waste from nuclear research and bomb making at federal sites around the country has chugged along, often at a pace that watchdogs and other critics say threatens public health and the environment. Now, fallout from the global coronavirus pandemic is resulting in more challenges as the Waste Isolation Pilot Plant, the nation's only underground repository for nuclear waste, finished ramping down operations Wednesday, April 1, 2020, to keep workers safe. (U.S. Department of Energy via AP, File)

FILE - In this March 6, 2014, file photo, empty nuclear waste shipping containers sit in front of the Waste Isolation Pilot Plant near Carlsbad, N.M. The U.S. government's efforts to clean up decades worth of Cold War-era waste from nuclear research and bomb making at federal sites around the country has chugged along, often at a pace that watchdogs and other critics say threatens public health and the environment. Now, fallout from the global coronavirus pandemic is resulting in more challenges as the Waste Isolation Pilot Plant, the nation's only underground repository for nuclear waste, finished ramping down operations Wednesday, April 1, 2020, to keep workers safe. (AP Photo/Susan Montoya Bryan, File)

FILE - In this April 2019 file photo provided by Los Alamos National Laboratory, barrels of radioactive waste are loaded for transport to the Waste Isolation Pilot Plant (WIPP) at the Radioactive Assay Nondestructive Testing (RANT) facility in Los Alamos, N.M. The U.S. government's efforts to clean up decades worth of Cold War-era waste from nuclear research and bomb making at federal sites around the country has chugged along, often at a pace that watchdogs and other critics say threatens public health and the environment. Now, fallout from the global coronavirus pandemic is resulting in more challenges as WIPP, the nation's only underground repository for nuclear waste, finished ramping down operations Wednesday, April 1, 2020, to keep workers safe. (Nestor Trujillo/Los Alamos National Laboratory via AP, File)

FILE - In this March 1999 file photo, the first load of nuclear waste arrives at the Waste Isolation Pilot Plant (WIPP) site in Carlsbad, N.M., from Los Alamos National Laboratory. The U.S. government's efforts to clean up decades worth of Cold War-era waste from nuclear research and bomb making at federal sites around the country has chugged along, often at a pace that watchdogs and other critics say threatens public health and the environment. Now, fallout from the global coronavirus pandemic is resulting in more challenges as WIPP, the nation's only underground repository for nuclear waste, finished ramping down operations Wednesday, April 1, 2020, to keep workers safe. (AP Photo/Thomas Herbert, File)