After years of debate and developing open space trails into Rocky Flats National Wildlife Refuge, a former bomb factory, warning signs are up.

LOS ALAMOS — A sphere of plutonium the size of a grapefruit contains enough energy to erase an entire city from existence. That single fact explains why nuclear weapons remain humanity’s most feared ...

Editor’s Note: An earlier version of this report stated this was the first time a worker who had inhaled plutonium was speaking publicly. Since then, we have learned that the Seattle Times spoke with ...

SEATTLE (AP) — 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 ...

(Reuters) - North Korea has offered to allow U.N. inspectors back to its nuclear facilities to make sure it is not processing highly enriched uranium, a U.S. state governor said on Tuesday after ...

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 ...