Overview

On a cold morning in December 1989, workers at the Rocky Flats Plant in Colorado loaded the last plutonium "trigger" for a nuclear warhead into a tractor trailer bound southeast to the Pantex Plant near Amarillo, Texas. No one knew then that the nuclear weapon built with this plutonium trigger would be the last one made in the United States for the foreseeable future. Until then, the production of nuclear weapons had run continuously, beginning during World War II with the startup of the first reactor to produce plutonium for the top-secret Manhattan Project. But growing concerns about safety and environmental problems had caused various parts of the weapons-producing complex to be shut down in the 1980s. These shutdowns, at first expected to be temporary, became permanent when the Soviet Union dissolved in 1991. The nuclear arms race of the Cold War came to a halt for the first time since the invention of the atomic bomb. Quietly, a new era had begun.

• The Manhattan Project
• The Cold War and the Nuclear Weapons Complex
• Civilian Control
• The Environmental Legacy of the Cold War
• Environmental Management
• Closing the Circle
• The Challenge Before Us