In a report describing the means by which terrorists might obtain and use such weapons, the agency said Osama bin Laden's network could easily build a radiological dispersal device, or "dirty bomb," that could be used to create panic and enormous economic damage, but not mass casualties.
The unclassified report was prepared last month by the agency's Directorate of Intelligence as a sort of tutorial for government disaster-response teams on al Qaeda's interest in weapons of mass destruction and the medical aspects of specific chemical and biological agents, CIA spokesman Bill Harlow said Tuesday.
The report reiterates the assertion that al Qaeda's ultimate goal is the use of chemical, biological, nuclear or radiological weapons to cause mass casualties. But it makes no claims about recent progress toward that goal.
"The success of any al Qaeda attack and the number of ensuing casualties would depend on many factors, including the technical expertise of those involved, but most scenarios could cause panic and disruption," the report said.
The terrorists have considered a wide range of toxic chemicals for attacks, the report said.
"Typical plots focus on poisoning foods or spreading the agent on surfaces to poison via skin contact, but some also include broader dissemination techniques," it added.
Construction of a dirty bomb is "well within" al Qaeda's capabilities, since radiological materials are relatively easy to obtain, the report said. Hospitals, universities, factories, construction companies and laboratories are possible sources for the material that al Qaeda could use, including Cesium-137, Strontium-90 and Cobalt-60, the report said.
The CIA also said it was possible that bin Laden's operatives would try to launch conventional attacks against elements of the U.S. nuclear industry to cause contamination, disruption and terror.
By Robert Burns