Weapons of mass destruction (WMD) is a term that has become increasingly familiar through its use in the media. Not everyone means precisely the same thing when they use the term, but the definition used by the U.S. military may be the simplest and most generally understood. WMD are:
. . . chemical, biological, radiological, or nuclear weapons capable of a high order of destruction or causing mass casualties (DOD, 2017).
The possibility that terrorists might resort to the use of WMD is of grave concern. The four types of WMD vary in their ability to cause damage, in their ease of production and use, in the kinds of physical and human damage they can be expected to cause, and in their likelihood of use by terrorist organizations.
All four types of WMD offer advantages and obstacles to those who would create and use them. Some require a certain level of skill, others require access to controlled or illegal substances, and still others require significant capital outlay and/or the cooperation of people in positions of security or power. Some weapons could produce significant damage and high death tolls, while the greatest effects of others would be widespread panic and expensive cleanup operations.
The Centers for Disease Control and Prevention (CDC) define bioterrorism as:
. . . biological agents (microbes or toxins) used as weapons to further personal or political agendas. Acts of bioterrorism range from a single exposure directed at an individual by another individual to government-sponsored biological warfare resulting in mass casualties. Bioterrorism differs from other methods of terrorism in that the materials needed to make an effective biological agent are readily available, require little specialized knowledge and are inexpensive to produce (CDC, 2017).
According to the CDC:
A chemical emergency occurs when a hazardous chemical has been released and the release has the potential for harming people’s health. Chemical releases can be unintentional, as in the case of an industrial accident, or intentional, as in the case of a terrorist attack (CDC, 2016).
Some chemicals that are hazardous have been developed by military organizations for use in warfare beginning in World War I. Examples are nerve agents such as sarin and VX, mustards such as sulfur mustards and nitrogen mustards, and choking agents such as phosgene. It might be possible for terrorists to get these chemical warfare agents and use them to harm people (CDC, 2016).
Since the world wars, there has been research and stockpiling of chemicals by many countries, but mutual deterrence has generally prevailed. In 1997 the United States ratified the Chemical Weapons Convention Treaty (CWC), agreeing to destroy any remaining stockpiles of chemical warfare agents no later than April 29, 2012 (CDC, 2016a). One hundred ninety-two countries have signed all or elements of the CWC, which not only requires destruction of chemical weapons but prohibits, among other things, developing, producing, acquiring, stockpiling, and transferring of these weapons (NTI, 2017).
One country that has not signed the CWC is Syria, and in 2013 Syrian president Bashar al-Assad did use chemical weapons against Syrian citizens who were rebelling against his autocratic government.
Many hazardous chemicals are used in industry (eg, chlorine, ammonia, and benzene). Others are found in nature (eg, poisonous plants). Some could be made from everyday items such as household cleaners. These types of hazardous chemicals also could be obtained and used to harm people, or they could be accidentally released (CDC, 2016).
The techniques for making destructive chemical weapons are well understood and the necessary equipment is commonly available. Once made, these weapons can be easily concealed. In 1995 a Japanese cult group known as Aum Shinrikyo made and dispersed the nerve agent sarin several times in the Tokyo subway, killing 17 people and sending 5,500 to the hospital. These incidents made it clear that even small groups could manage the manufacture and dispersal of deadly chemical weapons (NTI, 2015b,e).
Chemical weapons use the toxic properties of chemicals to cause harm, up to and including death. Only a relatively small amount of a chemical agent is needed to produce significant physical and psychological effects. Historically, chemical weapons have been the most widely used and proliferated type of WMD, but they receive far less attention than do biological and nuclear weapons (NTI, 2015b,e).
Biological weapons utilize microorganisms and natural toxins to produce disease in humans, animals, or plants, and “gram-for-gram, . . . are the deadliest weapons ever produced.” Derived from a variety of sources, these compounds, when paired with a delivery system, become weapons. The potential danger of a given weapon is measured by its lethality—how effectively it kills; its infectivity—how easily it spreads; and its virulence—how likely it is to cause disease. Other important considerations include how easily is it dispersed, whether it can be treated medically, whether there is a vaccine, what dose is needed to cause disease, and the compound’s stability (NTI, 2015a,e).
Chemical and biological weapons are financially and logistically easier to acquire than are radiologic or nuclear weapons. They will cause more casualties and have a greater psychological impact than conventional weapons, but cause less destruction than devices involving radiation. Chemical weapons are somewhat easier than other weapons for terrorist groups (or even individuals) to manufacture because the manufacturing knowledge is readily available, many precursor chemicals have legitimate uses and are thus legally available, there is poor security around these chemicals in some countries, and small chemical manufacturing equipment is commonly available.
Radiologic and nuclear weapons rely on the same sources for damage—explosive power and radiation—but there is a distinction in their forms. In addition, true nuclear weapons produce tremendous heat, which can cause burns and start fires. In the last fifty years, most radiation injuries have been the result of accidents; however, the intentional deployment of a nuclear or radiologic device is a potential terrorist threat.
Modern nuclear threats can be divided into five general categories:
Both radiologic and nuclear devices can damage and contaminate. Incidents involving simple devices like Radiation Exposure Devices (REDs) and Radiologic Dispersal Devices (RDDs)—any device that causes intentional dissemination of radioactive material without a nuclear detonation—would probably cause a limited number of casualties; however, those involving Improvised Nuclear Devices (INDs) and small nuclear weapons would result in mass casualties (ORISE, 2017; Waselenko et al., 2004; CISAC, 2002).
Radiologic Dispersal Devices (RDD)—commonly known as “dirty bombs”—are seen as more likely to be used by terrorists. These devices require little more skill than is needed to make a conventional bomb and their components are easier to acquire. RDDs utilize conventional explosives to disperse a radioactive material packaged in the device, as opposed to a nuclear device, which creates radiation with its explosion.
While it is unlikely that many people would die from radiation poisoning as a result of the explosion of an RDD, there would be some deaths and injuries and the costs of cleanup could be considerable. These devices are attractive to some groups because they are relatively easy to create, and they will not generally do a great deal of damage, but they will play on the heightened fear of radiation among the general public to cause widespread panic and disruption, which is often a group’s real goal. Because of this, public education and good response preparation are important counter measures (CISAC, 2002; NTI, 2015c,d,e; ORISE, 2017).
Nuclear weapons present significantly higher obstacles in terms of the skill needed to produce them and the financial and logistical support needed to acquire materials, prepare the devices, and transport them (Weiss, 2015). However, the potential for damage, injuries, and death is much higher because they are significantly more powerful weapons.