The first use of chemical and biological weapons has been traced back to the sixth century, before the common era, when the Assyrians poisoned their enemy's well with rye ergot.  Smallpox was even used as a biological weapon when the English gave the Indians, who were helping the French, smallpox infested blankets during the French and Indian War of 1754.  Japan started a biological warfare program in a lab called Unit 731, in 1937.  Investigation found that experiments of aerosolized anthrax was found on approximately one thousand human corpses.  The Japanese were also discovered of having planes drop plague infected fleas in China.
    The United States began research into using biological and chemical weapons as an offensive threat in 1943.  This was started because of a perceived German biological warfare threat.  In 1969, president Nixon stopped all offensive biological and toxin weapon production and research.  In 1953, the United States also had a medical defensive program , which still runs today.  The United States and other counties signed on the Prohibition of the Development, Production, and Stockpiling of Biological and Toxin Weapons, usually called the Biological Weapons Convention.  The treaty prohibits the stockpiling of biological agents for military purposes and also prevents research into offensive use  of biological agents.  Iraq and Soviet Union signed on this treaty however, despite the treaty, research continued in countries hostile towards the United States.
    In 1991, the first United Nations inspection of Iraq, after the Gulf War, found biological warfare capabilities.  Representatives of the Iraqi government admitted they had done research into the offensive use of anthrax, botulinum toxins, and other biological toxins.  Further information was found, in 1995, that Iraq was conducting research on several biological weapons.  Traces of toxins were found in fields and biological agents were found in rockets, bombs, and spray tanks.
    The threat of chemical and biological warfare has increased dramatically over the past two decades, with the number of counties researching the offensive use of these deadly weapons.  Russian president Boris Yeltsin said he would put an end to biological research, but their is no evidence of this.  There is great concern towards countries hostile to western democracies that there is a possibility of research and production of biological and chemical weapons.
    The threat of chemical and biological weapons being used against the United States is greater than ever right now.  Therefore, knowledge and education of this potential hazard is more crucial than ever.
 
 

References: NBC