As he swung open
the back door of his pawnshop recently in Prichard, Ala., there it
was: a silvery, lunch-box-sized industrial device with yellow
stickers that blared "CAUTION RADIOACTIVE."
"It was just sittin' in a five-gallon bucket," says the shop's
owner in a syrupy drawl. Police determined the device used by
repair crews to check for cracks in pipe welds had been stolen
from a pipeline-company truck six months earlier in nearby
But the unusual thing about this story isn't that the device was
stolen. It's that it was found.
That's because roughly 2 million small-but-valuable radioactive
contraptions are used in the US in everything from construction to
healthcare to scientific research. And every year, hundreds of them
are lost, stolen, even abandoned. Most are never retrieved, and
30,000 are unaccounted for, according to some estimates.
In the post-Sept. 11 era, that's giving experts cause for
concern: If these devices can turn up at an Alabama pawnshop, they
could just as easily be hoarded by terrorists to create "dirty
bombs" conventional explosives laced with radioactive
"If you were going around snatching these smaller devices over a
period of years and putting them all in a truck bomb, it could be as
powerful as a bomb with a single, big radiation source," says Edwin
Lyman, of the Nuclear Control Institute in Washington.
Clearly, not all small radioactive items would work as dirty-bomb
ammunition the radiation many emit is extremely weak. Still,
terrorists could create a dangerous weapon by combining several
dozen minor sources with a simple explosive, says Friedrich
Steinhausler, a Stanford University nuclear physicist.
The damage from a "dirty bomb" would depend on many things,
including the strength of the explosive, the amount of radioactive
material, and how far winds would spread the toxic particles.
Experts say such bombs could cause fatalities in the immediate area
of detonation and a range of health complications in a wider area.
Their real insidiousness would be in the low or moderate levels of
radiation spread, possibly requiring whole sections of a city to be
abandoned for years.
That's because radiation cleanup is, at best, expensive and
difficult sometimes impossible. In all, rather than being a
"weapon of mass destruction," a "dirty bomb" is more like a "weapon
of mass disturbance," says Dr. Steinhausler.
The threat has rattled federal regulators. The Nuclear Regulatory
Commission (NRC) is reviewing how the devices are monitored.
"We're looking at requiring licensees to increase security," says
John Hickey, chief of the NRC division that oversees the
But new measures might only include better locks and stronger
storage facilities, and some critics worry that isn't enough. In
general, they fault the NRC for overlooking the smaller radiation
devices and focusing instead on safety at higher-profile nuclear
The devices in question include practically harmless
emergency-exit signs that rely on radioactive isotope for power
rather than electricity, which can fail. If broken open, these could
expose a person to radiation less intense than a dentist's X-ray. By
contrast, the pencil-sized rods used to irradiate food are so
dangerous that direct exposure could be quickly fatal, say experts.
(This also makes stealing them very difficult.)
As for the pawnshop item, it contains a piece of iridium-192
that's smaller than a pea. The iridium is shielded by depleted
uranium to keep radiation from escaping. To use the device, crews
put the radiation source on one side of a pipe and a special film on
the other. The radiation creates an image that shows hidden cracks
or other weaknesses.
Experts say if a person stood within one foot of that unshielded
iridium nugget for two hours, they could receive a fatal radiation
The sheer number of such devices in use in the US makes detailed
tracking tough and mishaps common.
On March 15, a $6,000 radioactive moisture-density gauge used
to determine if fresh concrete has fully dried was reported stolen
from a Maryland construction site. Such devices typically contain
several grams of cesium-137, a highly radioactive material
especially dangerous because it can persist in the environment for
centuries and can work its way into the food chain. These devices
more than exit signs, for instance are what worry authorities.
They contain enough material to be dangerous, especially if combined
with other similar sources. Yet they aren't so toxic like
food-irradiation rods as to require complicated equipment or
advanced knowledge to handle.
In February, a Wisconsin paper manufacturer discovered it had
mistakenly shipped a radioactive device used to measure paper-pulp
density to China, according to NRC documents. An executive scrambled
and arrived ahead of the shipment. But when he was at lunch, the
shipment's containers were unloaded, and only a frantic search led
to the device. Apparently the initial confusion in Wisconsin was
caused because the device was coated in paper mulch that obscured
In 1998, 19 vials of cesium-137 disappeared from a Greensboro,
N.C., hospital, where they're used in medical treatments. Because it
happened around the time of the Final Four basketball tournament,
concern about terrorism was high. So the federal government tasked
its Nuclear Emergency Search Team with finding the vials, which were
In 1996, two stolen industrial cameras were sold to scrap-metal
dealers in Houston. After one was broken open, 11 adults and two
children were exposed to high radiation levels that experts say
significantly boosted the risk of later medical complications.
Converting items like these into "dirty bombs" is a real
possibility mostly because it requires only simple scientific
knowledge, say experts. "It's high school science, not rocket
science," says Stanford's Steinhausler.
But easier to track
One small upside of the radioactive materials in commercial use
is that they're typically easier to detect than more-potent elements
like plutonium. When covered with simple tinfoil, plutonium is
nearly impossible to detect, for instance. But even when shielded by
lead, cesium-137 can be tracked by sensitive detectors.
Finally, much of the problem comes down to economics. For
instance, it currently costs about $400 per cubic foot to dispose of
materials like cesium-137, says Lyudmila Zaitseva of Stanford's
Institute for International Studies. That's roughly 10 times the
amount of fines for improper disposal of the material. The lack of
high fines, she says, can lead to shoddy tracking even deliberate
Separately, Dr. Lyman observes that boosting the security of
these devices would add to already high costs in construction,
healthcare, and other fields. Whether it's worth it, he says, "is a
tough societal question."