All weapons of war are destructive of human life, but chemical and bacteriological (biological) weapons stand in a class of their own as armaments which exercise their effects solely on living matter. The fact that certain chemical and biological agents are potentially unlimited in their effects, both in distance and durability, and that their large-scale use could have irreversible effects on the balance of nature adds to the sense of insecurity and tension which the existence of this class of weapons engenders.
Chemical and biological weapons pose a special threat to civilians because the high concentrations in which they would be used in military operations could lead to significant unintended involvement of the civilian population within the target area and for considerable distances downwind. Protection can be afforded by masks, filter canisters, impermeable clothing, reduction of psychological stress (thermal stress) by use of "permeable" protective clothing (permeable to air and water vapour but not to toxic chemicals), detection and contamination of toxic chemicals, medical antidotes and medical treatment, and collective physical protection in shelters. However, the large-scale or, with some agents, even limited use of chemical and biological weapons where no protective measures exist, could cause illness to a degree that would overwhelm existing health resources and facilities.
Large-scale use of chemical and biological weapons could also cause lasting changes of an unpredictable nature in man's environment. The possible effects of chemical and biological weapons are subject to a high degree of uncertainty and unpredictability, owing to the involvement of complex and extremely variable meteorological, physiological, epidemiological, ecological and other factors. Although advanced delivery systems are required for the employment of chemical and biological agents on a militarily significant scale against large civilian targets, isolated and sabotage attacks requiring only simple delivery could be very destructive in certain circumstances with some of these agents.
The potential for developing an armoury of chemical and biological weapons has grown considerably in recent years, not only in terms of the number of agents but in their toxicity and in the diversity of their effects. Possible long-term effects of such warfare include: chronic illness caused by exposure to chemical and biological agents; delayed effects in persons directly exposed (causation of cancer, severe damage to the human foetus, and detrimental alterations in the human gene); organic, particularly nervous, damage which lasts throughout life, even though the person is not killed. Biological agents spreading from person to person can give rise to waves of secondary attack which, in diseases like plague, may continue for months or years after the event. Decontamination of persons and equipment could be required for persistent chemical and biological agents.
Concerns have been expressed that massive attacks may alter the ecological relationship between man and lower animal and insect vectors of diseases previously latent. Because most biological and chemical warfare agents are specific in action (against humans), broad-scale environmental impact is unlikely. In certain cases, biological warfare aimed at animals (in order to disrupt meat, poultry and dairy production) could have important ecological consequences. However, the large-scale use of herbicides as a method of warfare could have devastating effects of the environment.
The Romans believed that war was to be waged with weapons, not with poison (Armis bella no venenis geri). Modern efforts to ban chemical weapons date back to the the Brussels Declaration (1874), which prohibited the use of poisons and poisoned bullets in warfare. A subsequent declaration signed at the Hague Conference (1899), condemned the use of "projectiles the sole object of which is the diffusion of asphyxiating or deleterious gases. Despite these declarations, chemical weapons were used extensively during the First World War. Wide-spread public condemnation of their use led to the signing, in 1925, of the Geneva Protocol, which prohibits "the use in war of asphyxiating, poisonous or other gases, and of all analogous liquids, materials or devices", as well as "the use of bacteriological methods of warfare". While making the use of chemical or biological weapons illegal, the Protocol does not forbid their development, production, stockpiling or deployment, nor does it provide for mechanisms and procedures for dealing with violations. Recognizing the limitation of the Protocol, some 40 States, at the time of ratifying it, made reservations to the effect that it would not be binding on them with regard to States that failed to respect its prohibition. Recently, however, a considerable number of States have withdrawn their reservations.
The international community continued to seek a total ban on chemical weapons. In 1948, the UN Commission for Conventional Armaments defined chemical and bacteriological weapons as weapons of mass destruction. The first UN General Assembly resolution of the question of chemical and bacteriological warfare was adopted in 1966. In the following years, as many countries developed a modern chemical industry, the number of potential possessors of chemical weapons increased considerably; moreover, instances of actual hostile use of certain chemical caused great concern. In 1980, the Conference on Disarmament began working towards a convention on chemical weapons, but progress was evident only late in the decade, after some rapprochement had occurred with regard to the sensitive issues related to verification of implementation of a convention and after the former Soviet Union and the USA had advanced in their bilateral negotiations, In 1991, the war in the Persian Gulf with the possibility that chemical weapons might be used added urgency to efforts, and by the end of its 1992 session, the Conference had successfully concluded its negotiations on the chemical weapons Convention.
According to a 1994 USA Senate investigation, the USA government licensed the export to Iraq of highly toxic biological agents (Bacillus anthracis, Clostridium botulinum, Brucella melitensis and Clostridium perfringens), which were subsequently used by Saddam Hussein's forces against allied servicemen during the 1991 Gulf War. The attacks, involving "cocktails" of biological and chemical warfare agents (nerve gas, vesicant and blood agents, blister agents and biotoxins), are the prime suspect for the mystery illness known as Gulf Syndrome which has afflicted thousands of USA and British servicemen and, in many cases, their families too. In addition to the aforementioned disease organisms, shipments of E coli and genetic materials, and human and bacterial DNA were shipped directly to the Iraqi Atomic Energy Commission from at least 1985 to 1989. The biotoxic agents together and separately could account for many of the symptoms of Gulf Syndrome: chronic fatigue, vomiting, muscular spasms and general systemic illness. Children born to Gulf War veterans have exhibited unusually high rates of life-threatening illnesses and birth defects.