“I rise today to commemorate one of the most fateful days in the history of the State of Colorado, the day the Rocky Flats Nuclear Weapons Plant outside of Boulder nearly became America's own Chernobyl, some 30 years before that terrible accident in the Ukraine.”

Quoted by CNN, regarding the My Lai massacre. http://www.nytimes.com/2006/01/07/national/07thompson.html
Attributed

2019

1990s, Memoirs (1995)

Nobel lecture (2005)
Context: Since the Chernobyl accident, we have worked all over the globe to raise nuclear safety performance. And since the September 2001 terrorist attacks, we have worked with even greater intensity on nuclear security. On both fronts, we have built an international network of legal norms and performance standards. But our most tangible impact has been on the ground. Hundreds of missions, in every part of the world, with international experts making sure nuclear activities are safe and secure.
I am very proud of the 2,300 hard working men and women that make up the IAEA staff — the colleagues with whom I share this honour. Some of them are here with me today. We come from over 90 countries. We bring many different perspectives to our work. Our diversity is our strength.
We are limited in our authority. We have a very modest budget. And we have no armies.
But armed with the strength of our convictions, we will continue to speak truth to power. And we will continue to carry out our mandate with independence and objectivity.

Letter to Abigail Adams (3 July 1776); because of the official adoption of the United States Declaration of Independence two days later, the fourth of July rather than the second, became known as the U.S. Independence Day
1770s

Source: Outliers: The Story of Success

Interview (18 December 1997) http://www2.gwu.edu/~nsarchiv/coldwar/interviews/episode-21/turner1.html for CNN : Cold War. Episode 21 : Spies (14 March 1999)
1990s
Context: America and Russia have excessive numbers of nuclear weapons today because we treated nuclear weapons, at the end of World War II, like they were just bigger conventional weapons. If you have tanks, and the other side has more than you, you may be in trouble — or airplanes or ships or whatever. With nuclear weapons, it's not the same: they're too powerful, and at some point you just can't use any more, it's just not meaningful. But what happened was, we had the lead of course, because we invented them. The Russians tried to catch up with us; we tried to stay ahead of the Russians; they tried to catch up with us, and we just had a never-ending race upward. By the mid-Sixties, we realized this, but because of the Cold War mentality, politicians couldn't stand up and say, "I'm willing to have less than the Soviet Union," and so the race continued, but we tried to mitigate it by instituting an arms control process, which at first tried to cap and then later to reduce these numbers. … there's just no way you can actually use them; they become so destructive. I estimate that a couple of hundred nuclear weapons, not just on the center of cities, but on economic positions in the country, will drive a country to the point it will never recover, it will never be the same again. It will survive, but it'll be a totally different country. You don't need thousands to do that. There are only a few hundred cities of any size in even Russia or the United States, like 200, and you just don't need thousands of weapons to demobilize a country.

Nobel Prize lecture (2005)

Nobel lecture (2005)
Context: A good start would be if the nuclear-weapon states reduced the strategic role given to these weapons. More than 15 years after the end of the Cold War, it is incomprehensible to many that the major nuclear-weapon states operate with their arsenals on hair-trigger alert — such that, in the case of a possible launch of a nuclear attack, their leaders could have only 30 minutes to decide whether to retaliate, risking the devastation of entire nations in a matter of minutes.