Binary chemical weapon

Binary chemical weapons or munitions are chemical weapons wherein the toxic agent in its active state is not contained within the weapon. Rather, the toxin is in the form of two chemical precursors, physically separated within the weapon. The precursors are designed to be significantly less toxic than the agent they make when mixed, and this allows the weapon to be transported and stored more safely than otherwise. The safety provided by binary chemical weapons is especially important for people who live near ammunition dumps.

The chemical reaction takes place when the weapon is deployed. Firing the munition or other deployment action removes the barrier between the two precursors, so they can react with one another. Commonly, there is a final stage which utilizes a bursting charge to aerosolize and distribute the chemical agent.

Binary chemical weapons are chemical weapons within the scope of the chemical weapons convention and therefore their production, use and stockpiling is forbidden in most countries. As at least one of the individual chemicals is likely to be a Schedule 1 chemical for which large scale production is forbidden.

Examples
One example of a binary chemical weapon is the United States Army M687. In the M687, methylphosphonyl difluoride (military name: DF, a Schedule 1 chemical) and a mixture of isopropyl alcohol and isopropyl amine (known as OPA) are held in chambers within the weapon, separated by a partition. When the weapon is fired, acceleration causes the partition to break, and the precursors are mixed by the rotation of the weapon in flight, producing sarin nerve gas.

The Soviet Union and later Russian Federation experimented with binary weapons capable of mixing and distributing two agents that would work together in worsening the effects of the weapon, an example of which would be the combination of nerve agents with blister agents.

In popular culture
A miniature binary weapon is used in an assassination in the Frederick Forsyth novel The Devil's Alternative. It consists of two half-capsules, a non-resistant one containing potassium cyanide and an acid-resistant one containing hydrochloric acid. The substances mix after the halves are assembled and the seal between them is broken, and form hydrogen cyanide. The surplus acid eats through the capsule walls of the non-resistant half, and after a delay of several hours, the lethal content is released into the intestinal tract of whoever ingested it.

In the 10th and 11th episodes of the 6th season of TV-series Dexter are shown preparation and application of binary weapon consisting of two containers filled with DF and isopropyl alcohol. While contacting two substances forms sarin.

While technically possible, the assassination tool as discussed in the novel is presumably fictional. However, there are claims that in September 2003 the SVR (Russian Foreign Intelligence Service) prepared to assassinate Boris Berezovsky with a similar device.

The 2002 movie xXx features a Soviet-made binary chemical weapon codenamed "Silent Night", after its supposed ability to render an area silent by killing its inhabitants. In the movie, the chemical was acquired by the terrorist group Anarchy-99, and their leader, Yorgi, plans to launch missiles containing Silent Night from an autonomous solar-powered submarine called Ahab, with the intent to sow chaos among civilized nations as they all blame each other for the attacks.

In the 1995 movie Die Hard with a Vengeance, the terrorists use timer and otherwise activated binary explosive bombs, where two inert fluids, a white and a red coloured, right before detonation mixed by the bombs' mechanism creating a highly explosive mixture.