The M55 rocket was a chemical weapon developed by the United States in the 1950s. The United States Army produced both Sarin and VX unitary warheads for the M55.
The M55 rocket was a chemical weapon developed by the United States in the 1950s. The United States Army produced both Sarin and VX unitary warheads for the M55.
In 1951 the US Army Chemical Corps and Ordnance Corps initiated a joint program to develop a 115mm chemical rocket. The US Army Ordnance Corps designed the 115mm T238 and launcher in 1957 to provide the army a means to attack large area targets with chemical agents. Artillery and mortars are for small area targets; and due to different spin stabilities, warheads intended for explosives are not ideal for chemical delivery. The 115mm rocket was subsequently accepted as the M55 rocket with M91 launcher. Produced from 1959 to 1965, [1] the M55s were manufactured at Newport Army Ammunition Plant and tested at Aberdeen Proving Ground. [2] The Army produced unitary warheads filled with Sarin (GB) and VX nerve agents for the M55. [3]
During the 1960s the Army stored many M55s at Black Hills Army Depot. [2] The M55 was also stored at the Rocky Mountain Arsenal and in Okinawa, Japan. [2] The rockets in Japan were moved to Johnston Atoll during Operation Red Hat where they were destroyed during the 1990s.
Disposal operations for the M55 are made more difficult because of the rocket's design. [1] The rocket propellant was a double base composition nitroglycerin (NG) and nitrocellulose (NC) propellant. [2] Besides the NG and NC, M28 contains 2-nitrodiphenylamine (NDPA) as a stabilizer. [4] The rocket propellant cannot be removed from the warhead without cutting open the rocket. [5]
The propellant itself presents a hazard, because it becomes unstable as it ages. [6] Specifically, the danger of autoignition is present as the stabilizer ages and becomes depleted. [7] The U.S. National Research Council and other sources called the M55 the most dangerous weapon in the American chemical arsenal because of this and other hazards. [6] [7]
Another danger is agent leakage. Army reports have indicated that nerve agent GB can corrode the metal casings of the munitions over time. [1] As Sarin decomposes it forms acids which can corrode the aluminum casings found around the agent in the M55. [6] [8] M55 rockets containing GB have accounted for the majority of leaking American chemical weapons. [6] In mid-2002, over 4,000 munitions in the U.S. chemical stockpile were found to be leaking agent; of that number 2,102 were Sarin-containing M55s. [8]
The United States signed the Chemical Weapons Convention in 1993, which obligated it to destroy all chemical weapons by an extended deadline of April 2012. The U.S. missed the deadline, but completed the destruction of all declared chemical weapons on July 7, 2023, at Blue Grass Army Depot in Kentucky. [9] [10] [11] The final chemical weapon to be destroyed was a sarin nerve agent-filled M55 rocket. [12]
The M55 is 78 inches (2,000 mm) long and 4.44 inches (113 mm) in diameter. The 57-pound (26 kg) weapons can hold warheads filled with about 10 pounds (4.5 kg) of GB or VX. [2] The warhead comprises about 15 pounds (6.8 kg) total, and consists of several components. The M34 and M36 Burster utilize composition B or tetrytol and total about 3 pounds (1.4 kg) of the total weapon weight. The agent, as stated, comprises about ten pounds (4.5 kilograms) of the weight with the rest lying in the casing and M417 fuze. [2]
Chemical warfare (CW) involves using the toxic properties of chemical substances as weapons. This type of warfare is distinct from nuclear warfare, biological warfare and radiological warfare, which together make up CBRN, the military acronym for chemical, biological, radiological, and nuclear, all of which are considered "weapons of mass destruction" (WMDs), a term that contrasts with conventional weapons.
Sarin is an extremely toxic organophosphorus compound. A colourless, odourless liquid, it is used as a chemical weapon due to its extreme potency as a nerve agent. Exposure can be lethal even at very low concentrations, where death can occur within one to ten minutes after direct inhalation of a lethal dose, due to suffocation from respiratory paralysis, unless antidotes are quickly administered. People who absorb a non-lethal dose and do not receive immediate medical treatment may suffer permanent neurological damage.
VX is an extremely toxic synthetic chemical compound in the organophosphorus class, specifically, a thiophosphonate. In the class of nerve agents, it was developed for military use in chemical warfare after translation of earlier discoveries of organophosphate toxicity in pesticide research. In its pure form, VX is an oily, relatively non-volatile liquid that is amber-like in colour. Because of its low volatility, VX persists in environments where it is dispersed.
The United States is known to have possessed three types of weapons of mass destruction: nuclear, chemical, and biological weapons. As the country that invented nuclear weapons, the U.S. is the only country to have used nuclear weapons on another country, when it detonated two atomic bombs over two Japanese cities of Hiroshima and Nagasaki during World War II. It had secretly developed the earliest form of the atomic weapon during the 1940s under the title "Manhattan Project". The United States pioneered the development of both the nuclear fission and hydrogen bombs. It was the world's first and only nuclear power for four years, from 1945 until 1949, when the Soviet Union produced its own nuclear weapon. The United States has the second-largest number of nuclear weapons in the world, after the Russian Federation.
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 containers each holding 1 short ton GB or VX nerve agents or HD blister agent. All munitions had been safely destroyed by 2011 and base closure operations were still ongoing as of 2022.
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Anniston Chemical Activity was a U.S. Army chemical weapon storage site located in Alabama. The Army had stored approximately seven percent of the nation’s original chemical weapons stockpile at the Anniston Army Depot since the early 1960s. In August 2003, the Army began disposing of these weapons at the Anniston Chemical Agent Disposal Facility. Destruction of the base's stockpile of VX was begun on July 23, 2006. By December 2008, all of the VX on site had been destroyed. Destruction of mustard-filled munitions began on July 2, 2009 after several months of retooling. By July 2010, it had destroyed by incineration 75% of the depot's total stockpile including all 437 tons of GB (sarin) and all VX nerve agent on site. On September 22, 2011, the last mustard gas shells were burned, completing chemical weapons disposal at the facility. The facilities were scheduled for dismantlement by about 2013 and some of the weapon-handling equipment was planned for transfer to the depots at Kentucky and Colorado. Local government emergency departments are expecting to lose millions in annual funding from the federal government related to the presence of the chemical depot and as many as 1000 jobs will be cut on the base. According to the US Army Corps of Engineers the disposal and closure of Anniston Chemical Activity were completed on May 7, 2013. Following the closure, other uses for the incinerators were explored, but ultimately they were demolished.
Operation Red Hat was a United States Department of Defense movement of chemical warfare munitions from Okinawa, Japan to Johnston Atoll in the North Pacific Ocean, which occurred in 1971.
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Johnston Atoll Chemical Agent Disposal System (JACADS) was the U.S. Army's first chemical munitions disposal facility. It was located on Johnston Island, at Johnston Atoll and completed its mission and ceased operation in 2000.
The M121/A1 155 mm projectile was a chemical artillery shell designed for use by the U.S. Army. It was designed to be used with approximately 6.5 lb (2.9 kg) of GB or VX nerve agents.
The M34 cluster bomb was the first mass-produced United States Army weapon meant to deliver the chemical agent sarin (GB). A large stockpile of M34s was destroyed between 1973 and 1976.
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Throughout history, chemical weapons have been used as strategic weaponry to devastate the enemy in times of war. After the mass destruction created by WWI and WWII, chemical weapons have been considered to be inhumane by most nations, and governments and organizations have undertaken to locate and destroy existing chemical weapons. However, not all nations have been willing to cooperate with disclosing or demilitarizing their inventory of chemical weapons. Since the start of the worldwide efforts to destroy all existing chemical weapons, some nations and terrorist organizations have used and threatened the use of chemical weapons to leverage their position. Examples of the use of chemical weapons since World War II are Iraq’s Saddam Hussein on the Kurdish village Halabja in 1988 and their employment against civilian passengers of the Tokyo subway by Aum Shinrikyo in 1995. The efforts made by the United States and other chemical weapon destruction agencies intend to prevent such use, but this is a difficult and ongoing effort. Aside from the difficulties of cooperation and locating chemical weapons, the methods to destroy the weapons and to do this safely are also a challenge.
The United States chemical weapons program began in 1917 during World War I with the creation of the U.S. Army's Gas Service Section and ended 73 years later in 1990 with the country's practical adoption of the Chemical Weapons Convention. Destruction of stockpiled chemical weapons began in 1986 and was completed on July 7, 2023. The U.S. Army Medical Research Institute of Chemical Defense (USAMRICD), at Aberdeen Proving Ground, Maryland, continues to operate.
