As the Cold War ended, the United States began to close down it's extensive nuclear weapons production facilities. Many of these plants date back to World War II or the early 1950s. There had been complaints for years that sloppy administration had led to radioactive waste being left in places it shouldn't be. The Rocky Flats, Colorado plant was closed in 1989. It was the only plant that produced plutonium triggers for nuclear weapons. Since 1989, triggers for new weapons used refurbished triggers from older weapons that have been disassembled and retired. The new plant will cost as much as $4.4 billion (depending on capacity) and will begin production in 2020.