January 1986 Soviet President Gorbachev calls for disarmament by the year 2000

April 1986 Chernobyl Nuclear Reactor meltdown and fire occur in the Soviet Union. Massive quantities of radioactive material are released

December 1987 Soviet President Gorbachev and President Reagan sign the Intermediate-Range Nuclear Forces (NIF) Treaty, the first arms treaty signed by the superpowers calling for elimination of a whole class of weapons--intermediate range missiles

November 1990 Conference on Security and Co-operation in Europe formally ends the Cold War and reduces Warsaw Pact and NATO conventional forces

July 1991 The United States and Soviet Union sign historic agreement to cut back long-range nuclear weapons by more than 30% over the next seven years

December 1992 US Department of Energy's Office of Environmental Restoration and Waste Management (EM) and its predecessor agencies have decontaminated and dismantled over 90 contaminated facilities across the country

1993 US Department of Energy (DOE) continues to clean up the contamination from the last 50 years of the nuclear age

1994 President Bill Clinton and President Boris Yeltsin announce that, by the end of May, no country will be targeted by missiles of the United States or Russia