2. Whole lotta radiation going on
This cobalt-60 was used in agricultural research during the 1950s. National Agricultural Library.
Nuclear?
Yes. Annihilation? No.
The
idea of a dirty bomb brings to mind the 1986 meltdown at Chernobyl,
which spread tons of highly radioactive junk over a huge area, much of
it still too hot for human occupation.
An attack on a nuclear plant might release that amount of radiation, but not a dirty bomb. However, far less than 1 percent of Chernobyl's radiation could still cause some disease, plenty of panic, and huge economic losses. According to one U.S. government radiological-weapon expert, "We're not talking very much material. You can have a very hot sample with material that's almost not weighable. It could be dispersed over a large area, and you'd see it everywhere: on curtains, cars, your shoes."
Unfortunately, radioactive material may be surprisingly available. The U.S. Nuclear Regulatory Commission says about 375 packets of radioactive material are lost each year - in this country alone.
Much is also on hand in the former Soviet Union. For example, some of the radioactive thermal generators used to power remote beacons for shipping and aircraft have disappeared.
Capsules containing cesium-137 inside a stainless steel package truckin'
down the road. Cesium-137 is often mentioned as the guts of a dirty bomb.
Department
of Energy.
Although cooling ponds at nuclear reactors contain large amounts of radioactive material, it "would be hard to steal, extract and get into a configuration" for a dirty bomb, said the government expert. Still, the fission products, "are in the cooling pond because they have a long half-life. If they get in the environment, you have a substantial problem."
Dirty bombs could also be made from radioactive isotopes used to sterilize food and medical equipment, to treat cancer, or for industrial or medical testing.
Radioisotope thermoelectric generators are a compact source of electricity
for space missions and remote facilities. NASA.
Bombmaker: Off thyself
Arjun Makhijani, a physicist who heads the Institute for Energy and Environmental Research, says two good isotopes
for a dirty bomb are the readily available and highly radioactive cobalt-60
and cesium-137.
But that very lethality makes these isotopes tricky, he adds. "It's quite difficult to make these bombs. They are extremely dangerous to handle. If you don't have a shielded facility, and don't know what you're doing, you are much more likely to kill yourself first - they're that lethal."
Radioactive sources used at sterilization factories may be as big as a refrigerator and weigh a ton due to their lead shielding. Thus, Makhijani adds, "The difficulty of delivering these bombs is also very great. You can't just strap unshielded cesium 137 to yourself; it would kill you in minutes. You have to carry it shielded, so it should be impossible to carry it through airports, for example."
So a few bombers might kill themselves. But death does not deter today's terrorist. As the 9/11 bombers proved, unthinkable no longer equals impossible.
How much death and disease would a dirty bomb cause?
Simulation of long-term contamination due to a cobalt-60 bomb in New York
City. The bomb contained the amount of cobalt-60 found in one rod at a
food-irradiation facility. Cancer deaths due to radiation: Inner ring:
One per 100 people Middle ring: One per 1,000 Outer ring: One per 10,000
Courtesy Federation
of American Scientists.
How dangerous?
Dirty bombs spread radioactive isotopes which emit
ionizing radiation - alpha, beta and gamma radiation -- when they undergo
radioactive decay. The risk is twofold, observes Frank Ranallo, assistant
professor of medical physics and radiology at University of Wisconsin-Madison:
first, being exposed to ionizing radiation from radioactive isotopes in
the environment, and second, inhaling or ingesting the radioactive isotopes.
"Once inside the body, this radioactive material may continue to expose
you to radiation for an extended period of time, sometimes for your entire
life. So you can continue to be irradiated even after removing yourself
from the area of radioactive contamination. Also, some radiation that
may not be harmful if originating from outside the body (since your dead
layer of skin will stop it) can be very damaging if originating from radioactive
material inside the body."
Ionizing radiation is fearful, and without question, it can kill, maim and sicken, often many years after the exposure by inducing cancer. But, as with most environmental contaminants, it's the dose that makes the poison.
We're all exposed to a certain amount of "background" radiation in our hum-drum daily existence. In the United States, the average dose is 300 to 400 millirems, a level generally considered harmless. (Radiation is measured in millirems. 1,000 millirems = 1 rem.)
By common sense, that dose can't be very dangerous, which is just as well, considering that it's almost unavoidable.
So how dangerous is a dirty bomb? Hard to say, especially when you consider that:
The health effects of radiation are hotly contested. If you believe the "linear, no-threshold" model, any increase over background is dangerous. But if you believe the "threshold" model, small or even moderate increases may be safe.
The panic factor
Fear and panic are the most predictable outcome of
a dirty-bomb attack, especially if it's a truck bomb, as some simulations have assumed. Andrew Karam, radiation safety officer at
the University of Rochester, says radiation will star in a secondary
role: "The immediate effects will be the physical blast and panic from
setting off the device. The biggest source of risk would be people acting
recklessly."
Past radiological accidents, Karam adds, have been marked by psychosomatic illness. "People think they have radiation sickness, and flood the emergency rooms, and people who are legitimately ill can't get in. We've seen incidents where doctors were afraid to treat patients."
The panic sparked by a dirty bomb may resemble a larger version of last fall's anthrax attacks, says one government radiation expert. "A number of people died from anthrax, but that was small compared to the number affected by the panic."
After a couple of days, a dirty bomb could start to cost big money. Indeed, a 2002 report from the Federation of American Scientists said it may be impossible to decontaminate buildings, to which radioactive particles may adhere tightly. Even though a dirty bomb, unlike a crude nuclear weapon, would not kill tens or hundreds of thousands, it could still be expensive. "Since there are often no effective ways to decontaminate buildings that have been exposed at these levels," the report noted, "demolition may be the only practical solution. If such an event were to take place in a city like New York, it would result in losses of potentially trillions of dollars."
That's "trillions with a t," folks.
Like this: $1,000,000,000,000.
One seldom-discussed problem that the dirty-bomb threat raises is whether Environmental Protection Agency radiation standards are excessively restrictive. The Agency, Karam notes, projects that exposing 1 million people to 100 millirems above background would cause 500 extra cancer deaths. The Health Physics Society, notes Karam, contends that the effects of such low doses are not predictable. "For a total dose under 10 rems, they say it's not appropriate to calculate cancer risk because the numbers are too fuzzy. It's between very low and non-existent health effects. ... Maybe 500 is the most deaths you would expect, but I would not be surprised to see zero deaths, either."
"This is exactly correct. We do not really know the effects of radiation below 10 rem, only that they are small if they exist," agrees Ranallo.
While 500 deaths may sound scary, 250,000 out of every 1 million Americans will die of cancer without any help from dirty bombs, according to the American Cancer Society.
This Ohio facility stores a large amount of radioactive
material. Department
of Energy.
What to do?
If you're exposed to a dirty bomb, Karam says, "You
should go inside a car and sit still in the parking lot, or stay in the
building. Turn on a radio. If you get on the road, you're going to raise
the risk of traffic accidents and make it difficult for emergency responders
to help people hurt by the bomb explosion."
Cars and buildings offer some protection against radiation and radioactive particles, Karam says. "The ventilation system [in a building] will remove some things suspended in the air. It won't be perfect, but some particles will settle in the ductwork ... or an air filter. Every little bit helps."
If cure is expensive, what about a gram of prevention? As the U.S. government pursues nuclear terrorists, Makhijani advocates establishing a regular accounting of all nuclear material -- if the quantity would interest bombmakers, dirty or otherwise.
"All institutions that are licensed ... should be required to report regularly," he says. "We should have an inventory of what's out there." Even today, he says, the Fissile Materials Treaty is "stuck in Geneva. We don't even have universal tracking" of material that could be used to make regular nuclear weapons, let alone dirty bombs.
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