'Plot Would Have Killed Thousands'

Aug. 6, 2007 — -- Terrorists who had planned to detonate gel-based explosives on U.S.-bound flights from London last August would have achieved mass devastation, according to new information from Homeland Security Secretary Michael Chertoff in an exclusive interview with ABC News.

"I think that the plot, in terms of its intent, was looking at devastation on a scale that would have rivaled 9/11," Chertoff told ABC's Pierre Thomas. "If they had succeeded in bringing liquid explosives on seven or eight aircraft, there could have been thousands of lives lost and an enormous economic impact with devastating consequences for international air travel."

Sources tell ABC News that after studying the plot, government officials have concluded that without the tip to British authorities, the suspects could have likely smuggled the bomb components onboard using sports drinks.

The components of that explosives mixture can be bought at any drugstore or supermarket; however, there is some question whether the potential terrorists would have had the skill to properly mix and detonate their explosive cocktails in-flight.

But they can work — scientists at Sandia National Laboratory conducted a test using the formula, and when a small amount of liquid in a container was hit with a tiny burst of electrical current, a large explosion followed. (Click on the video player on the right side of this page to view the video.)

The test results were reviewed today by ABC terrorism consultant Richard Clarke, who said that while frequent travelers are upset by the current limits on liquids in carry-on baggage, "when they see this film, they ought to know it's worth going through those problems."

One official who briefed ABC News said explosives and security experts who examined the plot were "stunned at the extent that the suspects had gamed the system to exploit its weaknesses."

"There's no question that they had given a lot of thought to how they might smuggle containers with liquid explosives onto airplanes," Chertoff said. "Without getting into things that are still classified, they obviously paid attention to the ways in which they thought they might be able to disguise these explosives as very innocent types of everyday articles."

Tense Hours as Officials Learned of Plot

Chertoff speaks candidly about those moments when Homeland Security learned about the potential attack, and the terrorists had not yet been captured.

"This was very, very tightly held, because the British were concerned about any possibility of a leak getting out. Obviously, the intelligence folks knew, the senior intelligence folks, the president, senior leaders in the White House," he said. "Within my own department, only the deputy and I were initially told about this."

"I got a call telling me that it looked as if the focus had turned on an attack on the United States, specifically an attack on airliners leaving from Britain, traveling to American cities," Chertoff said. "It also became evident, within 24 hours, that the time frame within which the attack was going to take place, would not be a matter of months but … a matter of weeks or even days."

Airports in the United States and the United Kingdom were put on red alert — meaning a potential attack could be imminent — and liquids were banned from carry-on luggage as suspects were picked up, including 24 British-born Muslims and seven Pakistanis.

"We had to start about 9, 10 o'clock in the evening, when the arrests began to go down in Pakistan, and when we were first given the ability to tell other people about the plot," Chertoff said. "And we had to turn the entire process around by 6 a.m. the following morning, before people started to board airplanes.

"You had to change literally thousands of people's behavior in the course of about 12 hours. We had to train them. We had to get everybody to understand what the new rules were going to be. And you had to communicate to the public in a very short period of time.

"And so, we spent literally the entire night bringing in not only the TSA senior leadership, but also talking on the phone to the airline leadership, so that everybody would understand what needed to happen at 6 a.m. the following day," he said.

For Chertoff, the concern remained that an attack would have been carried out if they'd missed a critical detail. "There's an enormous sense of working against time, giving the analysts as much time as you possibly can, but always recognizing at the end that the benefit of the doubt has to be in favor of saving lives."

Assessing Current Risks

Since last August, the failed plot has had an enormous impact on U.S. airports, which have remained on orange — or high — alert, for nearly a year.

After authorities tested the explosive liquids, the government determined what quantity of liquid explosives could pose a risk if smuggled onboard flights, leading to the 3-ounce limit for carry-on bags.

Passengers are still restricted when bringing liquids onboard, and those rules may remain in place forever.

At the moment, Chertoff believes there is a "heightened risk" of an attack.

"We have seen that in some areas of Pakistan, the enemy has been able to reconstitute itself and get a breathing space, so to speak, where they can plan and do some recruiting and some training. We've seen increased effort to develop terrorist operatives in Europe.

"And, of course, the concern we have, because of the visa waiver program, has been Europeans either carrying out attacks against Americans on the European continent, or even coming to the United States," Chertoff said.

"When you add these things together, they don't move into a mathematical certainty we're going to have an attack, but they do suggest that there is a heightened threat, a bit more capability than there was, and, therefore, all the more reason for us to continue to raise the level of our security and our defenses," he said.

That progress was aided after the arrests last year that provided Homeland Security with information about terrorist capabilities.

"Clearly, the effort to put explosives in sports bottles was a reaction to what we had done with respect to other kinds of explosives, and … we're going to be back and forth with terrorists on this kind of cat-and-mouse process for years to come," Chertoff said.

And while he is confronted by pieces of data daily as Homeland Security tries to assess credible threats and piece together information, Chertoff said he remains continually struck by the nature of the enemy.

"You know, we go about our business during the summer, other times of the year. People are going to ballgames or watching their children graduate from high school," he said, "and it chills me sometimes to think there are people a half a world away who are spending the same period of time in a cave, trying to figure out how to kill us."