Arsenical Irritants 

Names	Structure	Molecular Formula	Chemical Abstracts Service Registry Number
DA, Diphenylarsinous chloride, Clark I, diphenylchloroarsine		C 12H 10AsCl	712-48-1
DC, Diphenylarsinous cyanide, Clark II, diphenylcyanoarsine		C 13H 10AsN	23525-22-6
DM, 10-Chloro-5,10-dihydrophenarsazine, Adamsite		C 12H 9AsClN	578-94-9

Background and History

Diphenylchloroarsine (DA), 10-chloro-5,10-dihydrophenarsazine (DM, Adamsite), and diphenylcyanoarsine (DC) are closely related chemical compound developed near the conclusion of World War I. All three compounds are solids when pure, and must be used as aerosols. These agents are used in either thermal grenades or smoke generators. The effects of all three are similar: severe irritation of the eyes, nose, and throat. If the agent is inhaled for 1-2 minutes, tightness of the chest and headache are experienced. The headache develops into general nausea, which can result in vomiting in approximately three minutes. Under concentrations expected to occur under combat conditions, fatalities are not expected; however, these compounds can be fatal at higher concentrations.

DA, the first in the series, was used by German troops in 1917. DA was considered a significant development because it penetrated the activated carbon gas mask filters deployed in World War I. Its irritant behavior was considered more important than its lethality. DA was used in combination with phosgene and diphosgene; DA caused victims to remove their masks to sneeze, cough, or vomit, rendering them vulnerable to the toxic effects of the other agents. DA alone saw some use as a riot-control agent up to the 1930s.

DC was used by the Germans in 1918. It was intended to combine the vomiting potential of DA with the lethality of cyanide. However, DC did not prove particularly lethal in tests.

DM was discovered by German scientists in 1913 (Ger. pat. appl. 281049, July 1913 to F. Bayer and Co.), but was never used by Germany. It was independently discovered by Major Robert Adams working at the university of Illinois and also by a British team, both at the beginning of 1918. DM was produced, but not used, by the Americans at the end of the war; Franke states that "according to very incomplete reports [it] was used by the Italian Army." It was produced by many nations for use as a riot control agent until it was superseded by alpha-chloroacetophenone (CN) and similar tear agents. It was also found to be effective as a pesticide against marine borers, which kept in production for years By 1920, gas mask filters had been improved to protect against aerosol particles, which may account for the termination of this line of development.

By mutual agreement, DA and DC are not to be used by any of the NATO members. Use of DA, DC, and DM against civilians was banned by the Western nations by the 1930s because of their nausea causing effects and the toxicity of their arsine-based by-products. There is documentation of limited Soviet production of DA in 1936. DC was a standard agent (Red No. 1) in the arsenal of the Japanese Imperial Forces between 1931 and 1945. Adamsite was prepared by all the belligerent states during World War II. Smoke generators filled with a mixture of Adamsite and alpha-chloroacetophenone were also developed. By 1967, protection had advanced to the point that the value of DA, DC, and DM in combat was considered questionable.

References

• Compton, J. A. F., Military Chemical and Biological Agents: Chemical and Toxicological Properties, Telford Press: Caldwell, NJ, 1988, pp. 194-204.
• Fedorov, L. A., Chemical Weapons in Russia: History, Ecology, Politics, Center of Ecological Policy of Russia: Moscow, 1994, pp. 12, 18. Translated from Russian by Foreign Broadcast Information Service.
• Franke, S., Manual of Military Chemistry, Volume 1. Chemistry of Chemical Warfare Agents, Deutscher Militîrverlag: Berlin (East), 1967. Translated from German by U.S. Department of Commerce, National Bureau of Standards, Institute for Applied Technology, NTIS no. AD-849 866, pp. 62-76.
• Kurata, H., Lessons learned from the destruction of the chemical weapons of the Japanese Imperial Forces, in Chemical Weapons: Destruction and Conversion, Stockholm International Peace Research Institute, Taylor and Francis: London, 1980, pp. 77-93.
• Stockholm International Peace Research Institute, The Problem of Chemical and Biological Warfare. A Study of the Historical Technical, Military, Legal, and Political Aspects of CBW and Possible Disarmament Measures. Vol. 1. The Rise of CB Weapons, Humanities Press: New York, 1971, pp. 40-41

Physical Properties

Taken from Franke, S., Manual of Military Chemistry, Volume 1. Chemistry of Chemical Warfare Agents, Deutscher Militîrverlag: Berlin (East), 1967. Translated from German by U.S. Department of Commerce, National Bureau of Standards, Institute for Applied Technology, NTIS no. AD-849 866, pp. 69, 73, 76.

	DA	DC	DM
Freezing point (ÉC)	38-40	32-35	195
Concentration in air at 20ÉC (mg L -1)	6.8 x 10 -4	1.5 x 10 -4	2 x 10 -5
Threshold limit (mg L Ç1)	10 -4	10 -5	10 -4
Water solubility	0.2 %	0.2 %	Practically insoluble
Solubility in organic solvents	soluble in halogenated alkanes, benzene, ethanol, acetone, ether	soluble in halogenated alkanes, benzene, ethanol, acetone, ether	slightly soluble in benzene, xylene, toluene, tetrachloromethane, acetic acid, alcohols

Methods for the Disposal and Destruction of DA, DC, and DM

There is evidence that the standard method of disposal of DM prior to 1970 was ocean dumping. In particular, there is documentation for the following events:

• 1600 metric tons of DM captured by the Soviets from the Germans were disposed at sea at the close of World War II.
• 375 tons of DM candles were dumped in Atlantic Ocean Dumping Area No. 1, (38É00'N 73É17'W to 38É10'N 73É30'W) by the U.S. during the period 14 September through 21 December 1945.
• 8,000 tons of DM candles were dumped in the Pacific Ocean 25 miles off Cape Moreton, Australia by the U.S. during the period 2 October through 20 December 1945.
• 35,000 tons of captured German CN/DM mixture was dumped in the Skagerrak area of the North Sea by the U.S. in December 1945.

In addition, during the period July 1946-August 1948, the U.S. conducted 11 "Davy Jones Locker" operations in the Atlantic, off Scotland and Norway, and in the Skaggerrak area of the North Sea to dump 28,500 long tons of unspecified captured German munitions. The agents almost certainly included a standard German agent, the thickened "winter mustard:" 23 percent phenyldichoroarsine (PD) and 19 percent DA mixed with 49 percent mustard and 9 percent thickening agents ( e.g., polystyrene, chlorinated rubber, wax).

3200 metric tons of DM were buried in 1960 at Shikany in Russia.

A German chemical agent incineration plant began operating at Munster in 1980. The plant operated a double chamber incinerator in batch mode. The second chamber of the incinerator operated at 1000ÉC. The agents destroyed in this plant included thickened "winter mustard" containing 19 percent DA. With one "arsenic-containing agent," the flue gas composition included 0.45 mole percent As ₂O ₃. To remove the arsenic, the flue gas was rapidly cooled to 80ÉC by injecting water. The incinerator included conventional alkaline scrubbers to remove HCl and SO ₂; in this instance the scrubber solution also contained Na ₃AsO ₃. The Na ₃AsO ₃ solution could not be discharged directly, therefore the scrubber solution was treated with permanganate or peroxide to give AsO ₄ ^-3 salts. The solution was then mixed with FeCl ₃ to precipitate FeAsO ₄. The effluent was then adjusted to pH 8, and with the arsenic values below 1 mg L ^-1, it was discharged.

It appears that hydrolysis is not suitable for decontamination of DA or DC; the diphenylarsinous acid hydrolysis product is strongly toxic.

References

• Brankowitz, W. R., Chemical Weapons Movement. History Compilation, Office of the Program Manager for Chemical Munitions (Demilitarization and Binary) (Provisional), Aberdeen Proving Ground, MD, SAPEO-CDE-IS-87001, 12 June 1987, AD-A193348.
• Brankowitz, W. R., Unpublished briefing materials.
• Fedorov, L. A., Chemical Weapons in Russia: History, Ecology, Politics, Center of Ecological Policy of Russia: Moscow, 1994, pp. 13, 34-35. Translated from Russian by Foreign Broadcast Information Service.
• Franke, S., Manual of Military Chemistry, Volume 1. Chemistry of Chemical Warfare Agents, Deutscher Militîrverlag: Berlin (East), 1967. Translated from German by U.S. Department of Commerce, National Bureau of Standards, Institute for Applied Technology, NTIS no. AD-849 866, pp. 62-76.