Question - What is mustard-lewisite (HL)?
Answer - The cited reference notes: “Mustard-Lewisite Mixture is a mixture of distilled mustard and lewisite developed to achieve a lower freezing point for ground dispersal and aerial spraying. 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% Lewisite and 37% Mustard. It has a garlic-like odor. Exposure to Mustard-Lewisite Mixture vapor induces immediate respiratory tract irritation and severe inflammation after a few hours latency period. Both agents are readily absorbed from the lungs.” (https://www.atsdr.cdc.gov/MHMI/mmg163.pdf; accessed December 2018)