Mustard/Lewisite (HL) blister agent (mixture)

Mustard/lewisite (HL) is a liquid mixture of distilled mustard (HD) and lewisite (L). Due to its low freezing point, the mixture remains a liquid in cold weather and at high altitudes. The mixture with the lowest freezing point consists of 63 percent lewisite (L) and 37 percent mustard (H). It has a garlic-like odor.

Exposure to mustard/lewisite vapor induces immediate respiratory tract irritation and severe inflammation after a few hours' latency period. HL, like its cousin...