Weapons of Mass Destruction (WMD) are weapons that literally cause "mass destruction". This term conventionally pertains to "NBC's" - nuclear, chemical, and biological weapons.
However, by definition landmines should be considered weapons of mass destruction. There are various definitions of "weapons of mass destruction" by experts. Nonetheless, one principle is uncontested: these weapons are not ordinary arms used in warfare and are dangerous to the lives of the people, not just military personnel.
Nuclear weapons are classified as being the most destructive of all the weapons of mass destruction. These weapons employ the most powerful reactions that exist in the scientific world. The reactions used are called nuclear reactions which effect the nuclei of the atoms. There are two types of nuclear reactions: fusion and fission. This type of weapon is so powerful that just a pound of uranium, for example, can produce the energy equivalent to a million gallons of gasoline. Due to the amount of destruction that these weapons cause, only two nuclear devices have ever been deployed in war. Many nations, however, retain the disputed right to conduct nuclear tests.
Chemical weapons use chemicals or toxins, that are harmful to humans as well as other organisms. Chemical warfare is less destructive than nuclear weapons and landmines. These weapons use chemical toxins or poisons in order to kill the victim. They do not cause massive destruction of land, but rather of living things. They rely on chemical effects rather than physical effects such as blast and heat. Chemical weapons can take the form of gases, liquids, or powders. During warfare, the chemicals used are known as Chemical Weapon Agents (CWA). About 70 chemical agents have been used in the 20th century.
Biological weapons include bacteria, viruses, and toxins when administered to the enemy will eventually kill them. Because of their characteristics, biological weapons can potentially kill plants, animals, and anything else that is living. Because biological weapons take time to mature and cause fatalities, this type of weapon is not usually used to obtain immediate results. Biological weapons are very dangerous because they have the ability to spread and kill even allies. They are difficult to contain. In 2001, weaponized anthrax was used in a biological terrorist attack against news media offices and government leaders in the United States.
There are two types of landmines: Anti-Personnel Mines, meant to be used against military personnel, and Anti-Tank Mines, meant to be deployed against tanks. These weapons don't seem as destructive as the traditional nuclear, biological, and chemical weapons; however, they have killed over a million innocent people worldwide. After war, some landmines set into the ground have never been found and taken out. To complicate matters, the removal of landmines takes time and costly. This leaves danger to local civilians as well as animals that may be passing through the area. These small devices are set off when a tank or victim steps or moves over the device. After this, the device is activated and destroys or severely maims the unknowing victim.