The agents in this class are dihalo organoarsines. Other than lewisite (C04-A002), which is listed in Schedule 1, these materials are not covered by the ChemicalWeapons Convention. Some of them have even seen limited commercial applications. The majority of these materials are ﬁrst generation chemical warfare agents employed
in World War I. They are moderately difﬁcult to synthesize and can be difﬁcult to disperse effectively. For information on someof the chemicals used tomanufacture arsenic vesicants, see the Component section (C04-C) following information on the individual agents. In addition to the agents detailed in this handbook, there are other arsenic vesicants
that were employed during World War I on a limited basis. However, there is little or no published information concerning the physical, chemical, or toxicological properties of these additional agents. Toward the end of World War I, lewisite (C04-A002) was developed, produced, and
weaponized but never used. Despite this, it has supplanted all other agents as the arsenic vesicant of choice and is the only one that was stockpiled in modern arsenals.