Radiological warfare

Radiological warfare is any form of warfare involving deliberate radiation poisoning or contamination of an area with radioisotopes, but without the use of nuclear weapons. While radiological weapons were researched and in some cases tested during the Cold War, there is no evidence any military has ever deployed operational radiological weapons, although they have been used for assassination.

Nuclear warfare, both via fission and fusion weapons, creates radioisotopes in the form of fission products and neutron-activated surface material. This fallout is incorporated into military planning. Neutron bombs are designed to maximize the lethal radiation area and minimize the blast. These uses are generally not considered direct radiological warfare, but salted bombs, which maximize radioisotope production in a nuclear blast, are.

Radiological weapons are normally classified as weapons of mass destruction (WMDs), with delivery methods explored including aerial dispersal and missile warheads. They can also be targeted at individuals, such as the assassination of Alexander Litvinenko by the Russian FSB, using radioactive polonium-210.

Numerous countries have expressed an interest in radiological weapons programs, several have actively pursued them. Radiological weapons have been tested in the United States, Soviet Union, Ba'athist Iraq, Israel, and China. Some evidence also exists that Egypt and North Korea pursued radiological weapons.

The United States and Soviet Union during the 1980s jointly attempted to promulgate a comprehensive prohibition treaty on radiological weapons via the Committee on Disarmament, but negotiations stalled over the prohibition of attacks on nuclear facilities, in the wake of the 1981 Israeli bombing of an Iraqi nuclear reactor.

The first high-activity radioactive material suitable for radiological warfare was produced in the reactor spent fuel of the Hanford Site, during the Manhattan Project. Over two months prior to the Trinity test, a calibration test was carried out using an assembly similar to a dirty bomb. On May 7, 1945, 108 tons of explosives dispersed a single slug irradiated at the Hanford Site to over 1,400 curies.

Prior to the Normandy landings, members of the Manhattan Project anticipated a risk that the German nuclear program had operational reactors and would use plutonium isotopes or fission products from the spent fuel as a radiological weapon. The Supreme Headquarters Allied Expeditionary Force authorized Operation Peppermint, to develop and distribute Geiger counters, film packets, and other radiation survey meters to detect radiological warfare.

The United States pursued research into an offensive radiological weapons program in the post-war period. Supporters included Ernest Lawrence and Edward Teller. Zirconium and niobium radioisotope fission products were originally considered, but tantalum-182 was concluded to be most effective. Inherently, a radiological weapons stockpile requires constant operation of production reactors, to replenish the rapidly decaying weapon material. This came into conflict with the infrastructure requirements of the emerging nuclear industrial complex, which was demanding all US production reactor capacity for plutonium, but especially the short half-life polonium-210, at the time crucial for neutron initiators.