Interview with Abel Gonzalez, Director, IAEA Division of Radiation and Waste Safety 15 June 2002
The Economist (http://www.economist.co.uk)
Ever since the September 11th attacks, it has been clear that the capacity of al-Qaeda and its affiliates to plot death and destruction is limited only by the power of the weapons they can obtain. Keeping nuclear, chemical and germ weapons out of their hands has therefore been a priority.The arrest of Abdullah al-Muhajir on suspicion of plotting to build and set off in America a radiological device - a "dirty bomb" that uses radioactive materials packed around a conventional explosive core - is an indication of how hard that fight will be.
Why a radiological bomb? Unlike chemical, biological or even the more familiar sort of nuclear-fission bombs, radiological weapons have never been used. Only Iraq's government is thought to have experimented with them for deployment on the battlefield. It is not just that they cause far fewer casualties than their atomic cousins. Like chemical and biological weapons, which are already outlawed, radiological weapons have long been considered inappropriate for military use. But for the al-Qaeda breed of terrorist, such weapons have value precisely for their power to shock.
All do-it-yourself mass-destruction weapons have their drawbacks. Nuclear fission bombs are devastating --think of Hiroshima and Nagasaki in 1945 --but require technical skills that would be hard, though not impossible, for terrorists to master. Getting hold of enough weapons-grade enriched uranium and plutonium is also not easy. Chemical weapons, by contrast, can be simply made from fertiliser or pesticides, though more deadly nerve agents need considerably more expertise. But you need a lot of chemical agent to produce a lot of casualties. Germ weapons can kill with much smaller doses --;either of viruses or bacteria -- but are hard to deliver effectively. The anthrax-laced letters sent through the United States postal system last year resulted in only 18 confirmed cases of the disease and seven deaths.
Radiological weapons have their drawbacks, too. Technically, they are not weapons of mass destruction at all. In most cases, the greater risk to those nearby would be from the conventional explosives used rather than the radioactive materials dispersed.
Even the long-term health effects of heightened radiation exposure after such a device exploded are quite uncertain, according to Abel Gonzalez, the director of radiation and waste safety at the Vienna-based International Atomic Energy Agency (IAEA). The Chernobyl nuclear accident in Ukraine in 1986, he points out, pumped vastly more radioactive material into the atmosphere than any imaginable "dirty bomb";, yet scientists are still trying to guess what real effect this will have on cancer rates among people exposed to fall-out from the radioactive plume that spread across Europe.
The point, says Mr Gonzalez, is that however uncertain the health effects, sensors can immediately pick up even a slight increase in background radiation. Given people's fears about radiation exposure, it would be panic, rather than the numbers of dead or damaged, that would give the terrorists their success. It is this psychological impact, combined with their ease of assembly, that makes radiological devices so attractive to terrorists.
First find your cesium
Officials trying to stem nuclear proliferation used to congratulate themselves that only a very few of the known incidences of trafficking involved the sort of uranium and plutonium useful for a bomb. Yet the black market in materials of the sort needed for a dirty bomb is much bigger. These materials include low-grade waste from power stations and small devices containing radioactive materials -- such as cesium-137, used in some cancer treatments, cobalt-60, used in food irradiation, or americum, incorporated in sensors for oil exploration.
Such materials have literally hundreds of applications in industry, medicine and university research, and they are scattered about the world accordingly. Although the IAEA has for some years been prodding governments to tighten up procedures, it is only recently that some of them have started to take notice. Controls over such devices are often poor, and get poorer still when the devices themselves have outlived their usefulness.
Every year in the United States, a couple of hundred such devices are known to go missing --lost, stolen or simply abandoned. The would-be dirty-bomber now in custody would not have had to look abroad for his materials. The record in other countries is often worse. This week, an IAEA-led team was fanning out in western Georgia in search of the remaining two of a batch of eight abandoned devices containing strontium-90, another radioactive element, which had been used in generators for communication stations. Similar generators with radioactive elements are known to litter remote parts of Russia.
Many governments keep no record of such "orphaned"; devices, although, over the years, they have been known to turn up in scrap metal without any terrorist involvement -- and, without use of any detonator, have still caused horrible damage. In 1987, a scrap-scavenger in Brazil unwittingly cut up a canister containing cesium powder which he had stolen from an abandoned clinic: the resulting contamination left several people dead and 28 with radiation burns. The clean-up produced 3,500 cubic metres of radioactive waste and left the local economy devastated.
Dirty bombs made of such materials might better be called weapons of mass dislocation. A recent study by the Federation of American Scientists tried to estimate the health and other effects of three relatively small bombs, detonated in either New York or Washington, designed to disperse radiation in quantities that might be found in a stolen medical device or some other industrial radiation source. Estimates of injury and damage, it is admitted, could be out either way by a factor of ten: much depends on the nature of the material used and on prevailing weather conditions. In each case, however, the number of immediate deaths and injuries was thought to be relatively low. It was decontamination, in areas from a few to dozens of city blocks, that posed the greatest challenge. Often the only solution would be demolition. It was these economic consequences, from the costs of cleaning up to longer-term damage to business, running together into tens or hundreds of billions of dollars, that proved devastating.