The M687 was an American

155 mm 155 mm (6.1 in) is a common, NATO-standard, artillery caliber. It is defined in AOP-29 part 1 with reference to STANAG 4425. It is commonly used in field guns, howitzers, and gun-howitzers. Land warfare The caliber originated in France aft ...

binary

sarin Sarin (NATO designation GB G-series, "B"">Nerve_agent#G-series.html" ;"title="hort for Nerve agent#G-series">G-series, "B" is an extremely toxic synthetic organophosphorus compound.chemical A chemical substance is a form of matter having constant chemical composition and characteristic properties. Some references add that chemical substance cannot be separated into its constituent elements by physical separation methods, i.e., w ...

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

. 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 Unite ...

Pine Bluff, Arkansas Pine Bluff is the eleventh-largest city in the state of Arkansas and the county seat of Jefferson County. It is the principal city of the Pine Bluff Metropolitan Statistical Area and part of the Little Rock-North Little Rock-Pine Bluff Combin ...

. Production was halted three years later, following the

1990 Chemical Weapons Accord On June 1, 1990, Presidents George H. W. Bush and Mikhail Gorbachev signed the bilateral U.S.–Soviet Chemical Weapons Accord; officially known as the "Agreement on Destruction and Non-production of Chemical Weapons and on Measures to Facili ...

between the United States and the

USSR The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, it was nominally a federal union of fifteen nati ...

, 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 226 sq. mi. and ...

, Nevada. America's remaining stocks were stored at the

Deseret Chemical Depot The Deseret Chemical Depot () was a U.S. Army chemical weapon storage area located in Utah, 60 miles (100 km) southwest of Salt Lake City. It is related to the Tooele Chemical Agent Disposal Facility. History The area was used to store chemi ...

, 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 storage co ...

(

Umatilla County, Oregon Umatilla County () is one of the 36 counties in the U.S. state of Oregon. As of the 2020 census, the population was 80,075. Hermiston is the largest city in Umatilla County, but Pendleton remains the county seat. Umatilla County is part of ...

). 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 G-series, "B"">Nerve_agent#G-series.html" ;"title="hort for Nerve agent#G-series">G-series, "B" is an extremely toxic synthetic 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 soma ...

(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. As an isopropyl group linked to a hydroxyl group ( chemical formula ) it is the s ...

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

hydrogen fluoride Hydrogen fluoride (fluorane) is an inorganic compound with the chemical formula . This colorless gas or liquid is the principal industrial source of fluorine, often as an aqueous solution called hydrofluoric acid. It is an important feedstock ...

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 function. In some applications, such as torpedoes, a fuze may be identified by function as the exploder. The relative complexity of even the earliest fuze ...

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

, 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 155mm artillery shells Chemical weapon delivery systems Chemical weapons of the United States

See also

External links