What Makes a Dirty Bomb?

June 11 - On Monday, the Bush administration announced it had arrested a man allegedly involved in a plot to make a “dirty” radiological bomb, renewing fears of more terrorist strikes—perhaps smaller—against the United States.

BUT WHAT EXACTLY are dirty bombs, how are they created, and what would be the short- and long-term effects of one detonated in a metropolitan center? “It’s not a nuclear explosion, there is no mushroom cloud,” says Joseph Cirincione, a director at the Carnegie Endowment for International Peace in Washington. “But if it’s created with reasonable care, even a small explosive could contaminate tens of square blocks of a city, making it uninhabitable.” The co-author of a new book, “Deadly Arsenals: Tracking Weapons of Mass Destruction,” Cirincione spoke with NEWSWEEK’s B. J. Sigesmund on Tuesday. (More information on the book can be found at www.ceip.org/deadly.)

NEWSWEEK: Please define a “dirty bomb.”

'The first time this thing happens it could be a dud,' says Cirincione

Joseph Cirincione: A dirty bomb—or a radiological bomb—uses conventional explosives such as dynamite to disperse radioactive materials over large areas. It’s a conventional explosion that disperses a cloud of radioactive particles.

How is it built?

The most common conception is to surround explosives with radioactive materials, preferably in the form of pellets or powder.

No one’s ever used a weapon like this, right? Not even the military.

The only known incident was in 1995, when Chechnyan rebels placed a vial of Cesium-137 with some explosives in a trash can in downtown Moscow. They then notified the press about this as a demonstration of their capabilities, but they didn’t explode the device.

There’s only one other incident I’m aware of. That was when Gen. MacArthur proposed laying down a barrier of radioactive Cobalt to stop the Chinese from crossing into Korea [in 1950]. But it was immediately rejected.

Where would a terrorist cell find radiological material kept in the United States?

There are thousands of sources of radiological material, starting with nuclear power reactors and nuclear research reactors. Also, a lot of radioactive materials have commercial applications; they’re used in geological surveying, in food irradiation, in cancer treatments involving radiotherapy. The Nuclear Regulatory Commission counts over two million licensed users of radioactive material in the U.S.

If a cell were to try to obtain some of it, how difficult would it be?

Most radioactive material is well-guarded and secure, and always has been. Most of the stuff is expensive, so people take care of it. However, the Nuclear Regulatory Commission reports that last year, there were 300 radioactive sources reported lost, missing or stolen.

Can you give us an example?

In February of this year, a container of Cesium from a medical apparatus turned up in a scrap metal site. So clearly, controls can be improved.

If a person were able to obtain the material, would it be hard to make the bomb?

If you can get the material, the rest is just the construction of a device. It’s not technically complicated. For maximum effectiveness, you’d want the radioactive material to be as finely ground as possible. The point is to disperse this as particles, not as large chunks.

Let’s talk about the scenario of a dirty bomb going off in a metropolitan center. Talk about the aftermath.

A lot would depend on the amount of the material released, the weather conditions and the particle size. But there was a recent case study done by Henry Kelly from Princeton, where he modeled the effects of 10,000 pounds of dynamite mixed with a small amount of Cesium in a device exploded outside of the National Art Gallery in Washington.

In that case, would all of D.C. be affected?

This model indicates that radioactive dust would spread over the Capitol, the Library of Congress and the Supreme Court. If such an event happened, the people in the buildings wouldn’t feel any immediate ill effects. We’re not talking about intensive exposure to radiation that would cause burns. Rather, this is closer to a cloud of asbestos descending on the building. That is, the radioactive particles would lodge in the building and ground and emit radioactivity.

Would these buildings be usable again?

The whole area would have to be cleaned or destroyed before human beings could use it again. In this country, we’ve never dealt with a radiation accident of this scale. It’s not clear if we could clean these buildings to clean them of radioactive dust. You can imagine how difficult and expensive and lengthy an operation this would be. It’s not like Anthrax, where you can fumigate and kill the particles. You can’t kill these particles. They would exist for thousands of years. You’d have to physically remove them.

Some experts say there would be widespread panic. But residents of New York and Washington didn’t panic after 9-11. Why would this be different?

It comes from the fear of the unknown. You’re told there’s a danger coming from something you can’t feel, see or touch. It’s exactly that kind of horror of terror that the terrorists are after. You would be told by the authorities there was nothing to worry about and there was no immediate danger—only that there might be longterm exposure. The natural reaction might be to flee the immediate area, or maybe the city. You just wouldn’t know.

In the Washington D.C. scenario, buildings would be unusable, perhaps forever, and even works of art would have to be destroyed, right?

It’s very possible. Supposed you blew up a bomb outside the National Gallery of Art and radioactive dust settled over all the artwork. The particles would become embedded in the artwork. How are you going to get it out? Cleaning it would destroy the art. That’s one example. Or suppose you did it at the U.S. Mint and dust covered not just the currency but the printing presses and plates. Or near a reservoir, or at the center of Wall Street. You could shut down Wall Street for months. Those are ten square blocks that are vital to the operation of this country.

You could foresee it having large effects on the economy, obviously.

You could render large areas of a city or a political capital unusable, costing billions of dollars for both clean-up and economic dislocation. This is a weapon of mass disruption, rather than mass destruction.

And you say the first time it happens, it might not even work.

Yes, since no one’s done it yet, the first time this thing happens it could be a dud. Instead of a big explosion with fine particles, you get a small explosion with chunks of radioactive metal, which are easily detected and cleaned up. There’s a panic and horror, but it ends very quickly. We shouldn’t paint these terrorists as Supermen.

What preventative measures can you suggest?

First, everyone using radioactive material should immediately take steps to increase the security of those materials. Don’t wait for the government, do it yourself. Second, the government should increase its vigilance in the tracking of these materials. The Nuclear Regulatory Commission needs to do a better job. It’s unacceptable that 300 radioactive sources go lost, stolen, or missing every year. Third, we should reduce the today’s use of these radioactive materials. There’s no reason to use Cobalt to kill bacteria in food. There are acceptable alternatives to increasing shelf life. We also use Cesium in oil exploration. There must be other alternatives.

© 2003 Newsweek, Inc.