Animal studies vesicants

Lewisite is markedly vesicant when applied to human skin, but vesication has not been observed in animals that have been studied. 

Agent HD (Sulfur Mustard). RfDe = 7 x 10 mg kg d. A LOiAEL was identified in a two-generation reproductive toxicity study conducted in rats. A total uncertainty factor of 3000 was applied to account for protection of sensitive subpopulations (10), animal-to-human extrapolation (10), LOAEL-to-NOAEL extrapolation (3), and extrapolation from a subchronic to chronic exposure (10). A LOAEL-to-NOAEL UF of 3, instead of the default value of 10, was used because the critical effect (stomach lesions) was considered to be mild in severity and may have been enhanced by the vehicle used (sesame oil in which sulfur mustard is fully soluble) and the route of administration (gavage), which is more likely to result in localized irritant effects. The key study did identify a toxic effect that is consistent with the vesicant properties of sulfur mustard. In none of the other available studies was there any indication of a different effect occurring at a lower exposure level. 

SM is widely known for its vesicating properties. There are no documented studies that conform to any standard regulatory test method for dermal irritation/corrosivity. However, there is sufficient information from observations and tests in humans to establish SM as a primary irritant, and further tests in animals are not required. 

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