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NWP 9 (Rev. A)

FMFM 1-10

Chapter 10 - Nuclear, Chemical, and Biological Weapons


Nuclear, chemical, and biological weapons present special law-of-armed-conflict problems due to their potential for indiscriminate effects and unnecessary suffering. This chapter addresses legal considerations pertaining to the development, possession, deployment, and employment of these weapons.

10.2.1 General.
There are no rules of customary or conventional international law prohibiting nations from employing nuclear weapons in armed conflict. In the absence of such an express prohibition, the use of nuclear weapons against enemy combatants and other military objectives is lawful. Employment of nuclear weapons is, however, subject to the following principles: the right of the parties to a conflict to adopt means of injuring the enemy is not unlimited; it is prohibited to launch attacks against the civilian population as such; and the distinction must be made at all times between persons taking part in the hostilities and members of the civilian population to the effect that the latter be spared as much as possible. The decision to authorize employment of nuclear weapons must emanate from the highest level of government. For the United States, that authority resides solely in the President.

10.2.2 Treaty Obligations. Nuclear weapons are regulated by a number of arms control agreements restricting their development, deployment, and use. Some of these agreements (e.g., the 1963 Nuclear Test Ban Treaty) may not apply during time of war. Seabed Arms Control Treaty. This multilateral convention prohibits the emplacement of nuclear weapons on the seabed and ocean floor beyond a 12-nautical mile coastal zone measured from the baseline of the territorial sea. The prohibition extends to structures, launching installations, and other facilities specifically designed for storing, testing, or using nuclear weapons. This treaty prohibits emplacements of nuclear mines on the seabed and ocean floor or in the subsoil thereof. It does not, however, prohibit the use of nuclear weapons in the water column that are not so affixed to the seabed (e.g., nuclear-armed depth charges and torpedoes). Outer Space Treaty. This multilateral convention prohibits the placement, installation, or stationing of nuclear weapons or other weapons of mass destruction in earth orbit, on the moon or other celestial bodies, or in outer space. Suborbital missile systems are not included in this prohibition. Antarctic Treaty. The Antarctic Treaty is a multilateral convention designed to ensure that Antarctica, defined to include the area south of 60 [degrees] South Latitude, is used for peaceful purposes only. The treaty prohibits in Antarctica “any measures of a military nature, such as establishment of military bases and fortifications, the carrying out of military maneuvers, as well as the testing of any type of weapons.” Nuclear explosions are specifically prohibited. Ships and aircraft at points of discharging personnel or cargo in Antarctica are subject to international inspection. Ships and aircraft operating on and over the high seas within the treaty area are not subject to these prohibitions. Treaty of Tlatelolco. This treaty is an agreement among the Latin American nations not to introduce nuclear weapons into Latin America. The treaty does not, however, prohibit Latin American nations from authorizing nuclear-armed ships and aircraft of nonmember nations to visit their ports and airfields or to transit through their territorial seas or airspace. The treaty is not applicable to the power system of any vessel.

Protocol I to the treaty is an agreement among non-Latin American nations that exercise international responsibility over territory within the treaty area to abide by the denuclearization provisions of the treaty. The Netherlands, the UK, and the US are parties to Protocol I. US territory within the Latin America treaty area includes Guantanamo Bay in Cuba, the Virgin Islands, and Puerto Rico. Consequently, the US cannot maintain nuclear weapons in those areas. Protocol I nations retain, however, competence to authorized transits and port visits by ships and aircraft of their own or other armed forces in their Protocol I territories, irrespective of armament of cargo.

Protocol II is an agreement among nuclear-armed nations (China, France, the USSR, the UK, and the US) to respect the denuclearization aims of the treaty, to not use nuclear weapons against Latin American nations party to the treaty, and to refrain from contributing to a violation of the treaty by the Latin American nations. Nuclear Test Ban Treaty. This multilateral treaty prohibits the testing of nuclear weapons in the atmosphere, in outer space, and underwater. Over 100 nations are parties to the treaty, including the USSR, the UK and the US (France and China are not parties.) Underground testing of nuclear weapons is not included within the ban. Non-Proliferation Treaty. This multilateral treaty obligates nuclear weapons nations to refrain from transferring nuclear weapons or nuclear weapons technology to non-nuclear-weapons nations, and obligates non-nuclear-weapons nations to refrain from accepting such weapons from nuclear-weapons nations or from manufacturing nuclear weapons themselves. The treaty does not apply in time of war. Bilateral Nuclear Arms Control Agreements. The United States and the USSR have concluded a number of bilateral agreements designed to restrain the growth of nuclear warheads and launchers and to reduce the risk of miscalculation that could trigger a nuclear exchange. Among these agreements are the Hotline Agreements of 1963 and 1971, the Accidents Measures Agreement of 1971, the 1973 Agreement on Prevention of Nuclear War, the Anti-Ballistic Missile Treaty of 1972 and its Protocol of 1974, the Threshold Test Ban Treaty of 1974, the 1976 Treaty of Peaceful Nuclear Explosions, the SALT Agreements of 1972 and 1977 (SALT I—Interim Agreement—has expired; SALT II was never ratified), and the INF Treaty of 1988.


Both customary and conventional international law prohibits the “first use” of lethal chemical weapons in armed conflict.

10.3.1 Treaty Obligations. The United States is a party to the 1925 Geneva Protocol for the Prohibition of the Use in War of Asphyxiating, Poisonous or Other Gases, and of Bacteriological Methods of Warfare (“the 1925 Gas Protocol”). All other NATO nations and all Warsaw Pact nations are also parties. The United States, the USSR, and most other NATO and Warsaw Pact nations conditioned their adherence to the 1925 Gas Protocol on the understanding that the prohibition against use of chemical weapons ceases to be binding with respect to nations whose armed forces, or the armed forces of the allies, fail to respect that prohibition. This, in effect, restricts the prohibition to the “first use” of such munitions, with parties to the Protocol reserving the right to employ chemical weapons for retaliatory purposes.

The 1925 Gas Protocol does not prohibit the development, production, testing, or stockpiling of chemical weapons, nor does it prevent equipping and training military forces for chemical warfare.

10.3.2 United States Policy Regarding Chemical Weapons. The United States categorizes chemical weapons under the three headings of lethal and incapacitating agents, riot control agents, and herbicidal agents. United States policy with respect to these three categories is summarized in the following paragraphs. Lethal and Incapacitating Agents. The United States considers the prohibition against first use of lethal and incapacitating chemical weapons to be part of customary international law and, therefore, binding on all nations whether or not they are parties to the 1925 Gas Protocol. Lethal chemical agents are those asphyxiating, poisonous, or other gases; analogous liquids; or materials that cause immediate death. Incapacitating agents are those producing symptoms that persist for appreciable periods of time after exposure to the agent has terminated. Because the 1925 Gas Protocol effectively prohibits only first use of such weapons, the United States maintains a lethal and incapacitating chemical weapons capability for deterrence and possible retaliatory purposes only. National Command Authorities (NCA) approval is required for retaliatory use of lethal or incapacitating chemical weapons by US Forces. Retaliatory use of lethal or incapacitating chemical agents must be terminated as soon as the enemy use of such agents that prompted the retaliation has ceased and any tactical advantage gained by the enemy through unlawful first use has been redressed. Riot Control Agents. Riot control agents are those gases, liquids, and analogous substances that are widely used by governments for civil law enforcement purposes. Riot control agents, in all abut the most unusual circumstances, cause merely transient effects that disappear within minutes after exposure to the agent has terminated. Tear gas and Mace are examples of riot control agents in widespread use by law enforcement officials. The United States considers that use of riot control agents in wartime is not prohibited by the 1925 Gas Protocol. However, the United States has formally renounced first use of riot control agents in armed conflict except in defensive military modes to save lives. Examples of authorized used of riot control agents in time of armed conflict include:

1. Riot control situations in areas under effective US military control, to include control of rioting prisoners of war.

2. Rescue missions involving downed aircrews or escaping prisoners of war.

3. Protection of military supply depots, military convoys, and other military activities in rear echelon areas from civil disturbances, terrorist activities, or paramilitary operations.

Use of riot control agents by US forces in armed conflict requires NCA approval.

Employment of riot control agents in peacetime may be authorized by the Secretary of Defense, or in limited circumstances, by the commanders of the unified and specified commands. Examples of authorized use of riot control agents in peacetime include:

1. Civil disturbances and other law enforcement activities in the United States, its territories, and possessions.

2. On US bases, posts, embassy grounds, and installations overseas for protection and security purposes, including riot control.

3. Off base overseas for law enforcement purposes when specifically authorized by host government.

4. Humanitarian evacuation operations involving US or foreign nationals. Herbicidal Agents. Herbicidal agents are gases, liquids, and analogous substances that are designed to defoliate trees, bushes, or shrubs, or to kill long grasses and other vegetation that could shield the movement of enemy forces. The United States considers that use of herbicidal agents in wartime is not prohibited by the 1925 Gas Protocol, but has formally renounced the first use of herbicides in time of armed conflict except for control of vegetation within US bases and installations or around their immediate defensive perimeters. Use of herbicidal agents during armed conflict requires NCA approval. Use of herbicidal agents in peacetime may be authorized by the Secretary of Defense or, in limited situations, by the commanders of the unified and specified commands.


International law prohibits all biological weapons or methods of warfare whether directed against persons, animals, or plant life. Biological weapons include microbial or other biological agents or toxins whatever their origin (i.e., natural or artificial) or method production.

10.4.1 Treaty Obligations. The 1925 Gas Protocol prohibits the use in armed conflict of biological weapons. The 1972 Convention on the Prohibition of the Development, Production and Stockpiling of Bacteriological (Biological) and Toxin Weapons and on Their Destruction (the “1972 Biological Weapons Convention”) prohibits the production, testing, and stockpiling of biological weapons. The 1972 Biological Weapons Convention obligates nations that are a party thereto not to develop, produce, stockpile, or otherwise acquire biological agents or toxins of types and in quantities that have no justification for prophylactic, protective, or other peaceful means, as well as weapons, equipment, or means of delivery designed to use such agents or toxins in armed conflict. All such materials were to be destroyed by the parties to the Convention by 26 December 1976. The United States, the USSR, and most other NATO and Warsaw Pact nations are parties to both the 1925 Gas Protocol and the 1972 Biological Weapons Convention.

10.4.2 United States Policy Regarding Biological Weapons. The United States considers the prohibition against the use of biological weapons during armed conflict to be part of customary international law and thereby binding on all nations whether or not they are parties to the 1925 Gas Protocol or the 1972 Biological Weapons Convention. The United States has, therefore, formally renounced the use of biological weapons under any circumstances. Pursuant to its treaty obligations, the United States has destroyed all its biological and toxin weapons and restricts its research activities to development of defensive capabilities.


Published: Wed Feb 14 08:22:10 EST 2018