What is the Real Nuclear or Biological Threat from al Qaeda?
The answer is, while the threat of a dirty bomb or biological attack is there, it is small. Al-Qaeda is simply not in the position to obtain or execute such attacks with any degree of effectiveness.
Had al-Qaeda been able to do so with a dirty bomb, they would have used it by now rather than risk it being captured or destroyed. Another issue about obtaining nuclear material to even make a dirty bomb is that other countries, like Iran, are seeking the same material from countries having it for sale, like North Korea. Thus, are unlikely to be able to outbid them. Even if they did acquire, they need experts to create a dirty bomb, so far, they have been unable to recruit these. U.S. aid to Russia to destroy or adequately secure such nuclear and radiological material increased dramatically following 9/11. In 2009, the U.S. Congress authorized around $1.2 billion for U.S. programs that provide nonproliferation and threat reduction assistance to the former Soviet Union. Such programs have resulted in a considerable amount of fissile material being taken off the market and removed from vulnerable storage sites. Making it much harder for rogue groups to find material for such a bomb. Nuclear material could only be bought from those countries, such as Pakistan, willing to sell it to them. So, far, Pakistan's Army remains in tight control and Iran has none to sell. Whatever amount they create is for them, they are not interested in selling it.
A dirty bomb easy to deploy, yet one has not been used within the United States. A dirty bomb is very difficult to immediately administer a lethal dose of radiation to victims. Thus, the “bomb explosion” part of a dirty bomb would likely kill more people than the device’s “dirty,” or radiation component. However, the result in mass panic, evacuations and expensive decontamination process would wreck havoc for sure.
As to al-Qaeda's ability to attack using a biological threat, it is more remote than nuclear dirty bombs. Deploying any sort of gas, such as Chlorine or Mustard, is difficult even for trained soldiers and the environmental conditions always may make it ineffective. A biological threat, as in some deadly virus, even seems more remote than gases. Like nuclear material, only a handful of governments have them and are tightly guarded. They are even more difficult to deploy in some cases.
In the end, the real threats from al-Qaeda and others remain with the bombs on people, bombs on trucks, bombs on kids, bombs of trusted persons, roadside bombs, remote control bombs, bombs in cars and airplanes.