"SEATTLE — For much of the 20th century, a sprawling complex in the desert of southeastern Washington state turned out most of the plutonium used in the nation’s nuclear arsenal, from the first atomic bomb to the arms race that fueled the Cold War.

Now, after decades of planning and billions of dollars of investment, the site is turning liquid nuclear and chemical waste at the Hanford Nuclear Reservation into a much safer substance: glass.

State regulators on Wednesday issued the final permit Hanford needed for workers to remove more waste from often-leaky underground tanks, mix it in a crucible with additives, and heat it above 2,000 degrees Fahrenheit (1,000 Celsius). The mixture then cools in stainless steel vats and solidifies into glass — still radioactive, but far more stable to keep in storage, and less likely to seep into the soil or the nearby Columbia River.

The long-awaited development is a key step in cleaning up the nation’s most polluted nuclear waste site. Construction on the Hanford Waste Treatment and Immobilization Plant began in 2002."

Cedar Attanasio reports for the Associated Press October 2, 2025. [2]