by nucleophilic attack using decontamination solutions such as "DS2" (2% NaOH, 70% diethylenetriamine, 28% 2-methoxyethanol). After initial decontamination of the victim's wounds is complete, medical treatment is similar to that required by any conventional burn. The degree of pain and discomfort suffered by the victim is also comparable. Mustard agent burns do not heal quickly, and (as with other types of burns) present a risk of sepsis caused by pathogens such as Staphylococcus aureus and Pseudomonas aeruginosa. The mechanisms behind mustard gas's effect on endothelial cells are still being studied, but recent studies have shown that high levels of exposure can induce high rates of both necrosis and apoptosis. In vitro tests have shown that at low concentrations of mustard gas, where apoptosis is the predominant result of exposure, pretreatment with 50 mM N-acetyl-L-cysteine (NAC) was able to decrease the rate of apoptosis. NAC protects actin filaments from reorganization by mustard gas, demonstrating that actin filaments play a large role in the severe burns observed in victims. A British nurse treating soldiers with mustard agent burns during World War I commented: Formulations In its history, various types and mixtures of mustard gas have been employed. These include: H – Also known as HS ("Hun Stuff") or Levinstein mustard. This is named after the inventor of the "quick but dirty" Levinstein Process for manufacture, reacting dry ethylene with disulfur dichloride under controlled conditions. Undistilled mustard gas contains 20–30% impurities, which means it does not store as well as HD. Also, as it decomposes, it increases in vapor pressure, making the munition it is contained in likely to split, especially along a seam, releasing the agent to the atmosphere. HD – Codenamed Pyro by the British, and Distilled Mustard by the US. Distilled mustard of 95% or higher purity. The term "mustard gas" usually refers to this variety of mustard. HT – Codenamed Runcol by the British, and Mustard T- mixture by the US. A mixture of 60% mustard and 40% O-mustard, a related vesicant with lower freezing point, lower volatility and similar vesicant characteristics. HL – A blend of distilled mustard (HD) and lewisite (L), originally intended for use in winter conditions due to its lower freezing point compared to the pure substances. The lewisite component of HL was used as a form of antifreeze. HQ – A blend of distilled mustard (HD) and sesquimustard (Q) (Gates and Moore 1946). Commonly-stockpiled