The M687 was an American

155 mm The 155 mm calibre is widely used for artillery guns. Land warfare Historic calibres France - 1874 The caliber originated in France after the Franco-Prussian War (1870–1871). A French artillery committee met on 2 February 1874 to dis ...

binary Binary may refer to: Science and technology Mathematics * Binary number, a representation of numbers using only two values (0 and 1) for each digit * Binary function, a function that takes two arguments * Binary operation, a mathematical op ...

sarin Sarin (NATO designation GB nerve_agent#G-series.html" ;"title="hort for nerve agent#G-series">G-series, "B" is an extremely toxic organophosphorus compound.chemical A chemical substance is a unique form of matter with constant chemical composition and characteristic properties. Chemical substances may take the form of a single element or chemical compounds. If two or more chemical substances can be combin ...

artillery shell A shell, in a modern military context, is a projectile whose payload contains an explosive, incendiary device, incendiary, or other chemical filling. Originally it was called a bombshell, but "shell" has come to be unambiguous in a military ...

. The design was standardized in 1976 and production began on December 16, 1987 at

Pine Bluff Arsenal The Pine Bluff Arsenal is a United States Army installation in Jefferson County, Arkansas, about eight miles northwest of Pine Bluff and thirty miles southeast of Little Rock. Pine Bluff Arsenal is one of nine Army installations in the United ...

Pine Bluff, Arkansas Pine Bluff, officially the City of Pine Bluff, is the List of municipalities in Arkansas, tenth-most populous city in the U.S. state of Arkansas and the county seat of Jefferson County, Arkansas, Jefferson County. The population of the city wa ...

. Production was halted three years later, following the 1990 Chemical Weapons Accord between the United States and the

USSR The Union of Soviet Socialist Republics. (USSR), commonly known as the Soviet Union, was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 until Dissolution of the Soviet ...

, and the dismantling of existing stocks began in November 1997 at

Hawthorne Army Depot Hawthorne Army Depot (HWAD) is a U.S. Army Joint Munitions Command ammunition storage depot located near the town of Hawthorne in western Nevada in the United States. It is directly south of Walker Lake. The depot covers or and has sto ...

, Nevada. America's remaining stocks were stored at the Deseret Chemical Depot, Utah, and the

Umatilla Chemical Depot The Umatilla Chemical Depot (UMCD), based in Umatilla, Oregon, was a U.S. Army installation in the United States that stored chemical weapons. The chemical weapons originally stored at the depot consisted of various live munitions and storag ...

(

Umatilla County, Oregon Umatilla County () is one of the List of counties in Oregon, 36 counties in the U.S. state of Oregon. The population of 81,826 ranks it as the 14th largest in Oregon, and largest in Eastern Oregon. Hermiston, Oregon, Hermiston is the largest ci ...

). The shell contained two canisters separated by a rupture disk. The compartments were filled with two liquid precursor chemicals for

sarin Sarin (NATO designation GB nerve_agent#G-series.html" ;"title="hort for nerve agent#G-series">G-series, "B" is an extremely toxic organophosphorus compound.methylphosphonyl difluoride Methylphosphonyl difluoride (DF), also known as EA-1251 or difluoro, is a chemical weapon precursor. Its chemical formula is CH3POF2. It is a Schedule 1 substance under the Chemical Weapons Convention. It is used for production of sarin and so ...

(denominated DF) and a mixture of

isopropyl alcohol Isopropyl alcohol (IUPAC name propan-2-ol and also called isopropanol or 2-propanol) is a colorless, flammable, organic compound with a pungent alcoholic odor. Isopropyl alcohol, an organic polar molecule, is miscible in water, ethanol, an ...

and isopropyl amine (denominated OPA) is in a second canister. The isopropyl amine binds the

hydrogen fluoride Hydrogen fluoride (fluorane) is an Inorganic chemistry, inorganic compound with chemical formula . It is a very poisonous, colorless gas or liquid that dissolves in water to yield hydrofluoric acid. It is the principal industrial source of fluori ...

generated during the chemical reaction. When the shell was fired the force of the acceleration would cause the disk between them to breach and the spinning of the projectile facilitated mixing. The two precursor chemicals would react in flight to produce sarin and when the shell reached its target the sarin would be released. The shells were meant to be stored and transported with only the OPA compartment loaded; the

fuze In military munitions, a fuze (sometimes fuse) is the part of the device that initiates its function. In some applications, such as torpedoes, a fuze may be identified by function as the exploder. The relative complexity of even the earliest fu ...

and the DF compartment would be inserted shortly before firing. The M687 was never used in combat and, under the

Chemical Weapons Convention The Chemical Weapons Convention (CWC), officially the Convention on the Prohibition of the Development, Production, Stockpiling and Use of Chemical Weapons and on their Destruction, is an arms control treaty administered by the Organisation for ...

, the U.S. destroyed the shells and the precursor chemical DF as part of its agreement to eliminate all chemical weapons. More than 258,000 of the shells were shipped to

from their storage at Deseret Chemical Depot, Utah, and the

, Oregon and were destroyed by July 1999. The last of the U.S.'s stockpile of DF was destroyed on April 6, 2006.

External links

The M687 @ The Federation of American Scientists

The U.S. Army Chemical Materials Agency (CMA) - Binary Chemical Weapons
{{U.S. chemical weapons 155 mm artillery shells Chemical weapon delivery systems Chemical weapons of the United States

See also

External links