The government’s second grounding of crop dusters in the wake of the Sept. 11 terrorist strikes on the Pentagon and World Trade Center is a chilling reminder that those devastating airline hijackings may not be the worst that can happen. We must also defend our country against the threat of biological and chemical weapons of mass destruction.

Before the attacks, the men believed to have been the perpetrators of the attacks visited a municipal airport in Florida and asked many questions about crop-dusting aircraft. There is a possibility that some of the men connected to the terrorist network recently applied for and received licenses to drive trucks that haul hazardous materials.

It has been known for some time that Osama bin Laden has been seeking to obtain chemical weapons. Although controversy surrounded President Bill Clinton’s cruise missile strike on a Sudanese pharmaceutical plant, Clinton maintained that the factory had links to bin Laden and had made chemical weapons. Recent satellite photographs of eastern Afghanistan have shown dead animals around an apparent laboratory used for experimentation with weapons of mass destruction.

All of these developments raise the ugly, but very real, possibility that terrorists, especially bin Laden and his organization, might attempt to use such super weapons in a cataclysmic strike on the United States. In the future, that possibility is not remote. Department of Defense officials and publications have long warned of their potential. So the question is not if, but how is the United States preparing to meet the threat of an attack using nuclear, biological or chemical weapons.

Of the three types of weapons, chemical and biological agents are probably the most likely to be used in an attack (nuclear-bomb making requires sizeable infrastructure and fissionable material that is under international control). Sprayers, including crop-dusting aircraft, are the most likely means of delivering those agents. According to a Defense Department report, “the low technology required lends itself to proliferant and even potential terrorist use.”

Chemical and biological agents are fairly easy to produce using readily available commercial materials and technologies. Such agents can be produced in commercial facilities, including dairies and wineries for biological weapons and fertilizer factories and chemical and pharmaceutical plants for chemical weapons. Even if produced overseas, small quantities of agents needed would be easy to smuggle across the thousands of mile of U.S. borders. U.S. intelligence might not be able to detect and interdict such shipments or even detect the activities of the potential perpetrators (a lesson learned from attacks on Sept. 11).

Of the two types of weapons, biological agents are much more lethal, but also more difficult to make into weapons, than chemical agents. Chemical weapons are easier to make and use and would probably be the first choice of terrorists. In the future, however, if terrorist groups recruit competent scientists and engineers, even biological weapons may become a threat to the U.S. homeland. If employed properly under the right environmental conditions, chemical weapons could kill thousands or tens of thousands of people and biological weapons could kill tens or hundreds of thousands.

Mitigating the effects of such catastrophic attacks would be difficult. A major problem is detecting them before it is too late. Police, fire, paramedical and hospital resources would probably be easily overwhelmed. Currently, a shortage exists of vaccines and antidotes for the major biological and chemical agents. In addition, it would be cost-prohibitive to provide protective suits and masks for every American citizen. Yet Secretary of Health and Human Services Tommy Thompson insisted recently on national television that the United States is well prepared to meet the threat of these weapons.

If the U.S. government is more honest with its citizens, it will tell them that if a terrorist successfully masters the use of biological or chemical weapons, the governmental response will help society only at the margins. In the short-term, the U.S. government needs to beef up human intelligence capabilities to get better warning of any such attack (unfortunately intelligence is not perfect and the terrorists only have to get lucky once) and to continue to provide training, medical supplies and equipment (for example, detection devices and protective masks and suits) for local emergency workers. In addition, the government may want to spend more money on stockpiling vaccines and antidotes.

In the long-term, the U.S. government must ask itself hard questions about what motivates terrorist groups to attack U.S. targets in 47 percent of the world’s terrorist incidents. Perhaps the U.S. government could initiate changes in its foreign policy that would make the United States less of a target for such attacks. U.S. military interventions overseas are a lightning rod for terrorism-for example, bin Laden’s major objection to U.S. foreign policy is the U.S. military presence in Saudia Arabia. The United States should adopt a policy of military restraint whereby it intervenes overseas, especially in the Middle East, only when its vital interests are at stake.