Mustard thickened

Agent T is out of production. It was created in the mid 1930s and used alone in warm climates or as a distilled mustard thickener. It is obsolete as a pure agent, and semi-obsolete as a mixer. 

A. One of the most difficult aspects of chemical warfare is that the chemical agents may persist in the environment for extended periods of time. This is especially true of agents such as VX, the mustards, thickened GB, or GD, which may remain as contact hazards for hours or days. 

After starting the project CWS learned that the British had already determined the best size for high altitude droplets and were adding various substances to mustard to increase the particle size. In co-operation with the NDRC the CWS tested more than seventy thickeners. Finally, the search narrowed down to polystyrene and methyl methacrylate. After methyl methacrylate sheet scrap (Plexiglas and Lucite) became available from aircraft factories, the CWS adopted it as a mustard thickener. ... 

W Mustard thickened with a 5 percent solution of methylmethacrylate... 

There are seven sites in the United States where U.S. Unitary Chemical Stockpile exists. Below they are listed by chemical weapon as follows GB, sarin H, mustard HD, mustard HT, mustard VX, persistent nerve agent GA, tabun L, lewisite TGA, thickened tabun TGB, thickened sarin. 

No 6 Mk 1, Type 1 No 6 Mk 1 and Type 4 No 6 Mk 1 Bombs were filled with mustard gas thickened with methacrylate polyvinyl alcohol (pp 56—7) ... 

The Army s interim RfD of 7 x 10 mg/kg per day for sulfur mustard was based on an oral two-generation reproductive toxicity study in rats, in which thickening of the forestomach epithelium was observed. The subcommittee agrees that this study is the best available one from which to derive the RfD for sulfur mustard and concludes that the interim RfD for sulfur mustard is scientifically valid. However, the subcommittee recommends adjustments in two of the uncertainty factors used to derive that RfD. Although the adjustments do not change the RfD for sulfur mustard, the subcommittee believes that they are scientifically justified and should be reflected in the Army s supporting documentation for the RfD. 

Information on the acute oral toxicity of sulfur mustard is quite limited. The oral LDl, for humans has been estimated to be 0.7 mg/kg (DA, 1992). The oral LD50 for rats is 17 mg/kg (DA, 1974). Rats treated with 2.5 mg/ kg/day for 14 days developed inflammation, petechial hemorrhage, thickening, and sloughing of the gastric mucosa (Hackett et al., 1987). 

Hobson, D., Blank, J., Menton, R. (1985). Comparison of effectiveness of 39 experimental decontamination systems and evaluation of the effect of three pretreatment materials against percutaneous application of soman, thickened soman, VX, and sulfur mustard to the rabbit. Aberdeen Proving Ground, MD. MREF Task 85-12. 

In another study, clipped rabbits were exposed to sulfur mustard, lewisite (L), thickened soman, and VX and were decontaminated between 30 s and 5 min postexposure. Eor the vesicants (sulfur mustard and L), lesion areas were compared. Decontaminating for 1 min resulted in the lesion areas being reduced 21-fold for sulfur mustard and 22-fold for L, relative to no decontamination. For the nerve agents (soman and VX), the inhibition of blood acetylcholinesterase (AChE) was used as a marker. Using a 2 min decontamination time, the dose of nerve agent required to produce 50% inhibition of AChE was increased 1.8-fold for thickened soman and 18-fold for VX (Hobson et al., 1993). 

L, VX, and thickened sulfur mustard. However, it ranked last in decontaminating sulfur mustard... 

BR3KHH HTIPHTA (Russian for thickened mustard) A018 C07 153... 

Sulfur mustard, although usually referred to as mustard gas , is actually a liquid that boils at 217°C. Most available information characterizes the distilled or purified form of sulfur mustard (HD bis(2-chloroethyl)sulfide) in contrast to the undistilled form (H) which contains numerous impurities. Agent HT was made by an older manufacturing process and contains about 60% HD and 40% agent T (bis(2-(2-chloroethylthio)ethyl)ether) to lower the freezing point of the blend for deployment in cold-weather operations. The HT blend also contains a variety of impurities. In some cases, solvents such as benzene or thickeners such as polyacrylates were added to HD to change the melting point. 

The primary environmental fate mechanism followed by stored or buried HD is hydrolysis. Although HD is rapidly hydrolyzed (a half-life of 4 to 8 min at 25° C in distilled water has been reported [Bartlett and Swain, 1949]), the overall process of hydrolytic destruction is limited by the very low water solubility of HD. Intermediate hydrolysis products and/or water-insoluble thickeners that can coat or encapsulate droplets of mustard retard hydrolysis. Because of low water solubility and formation of intermediate products, bulk amounts of HD may persist undispersed under water for some time. However, HD dispersed as droplets or mist, as in the case of an aerial attack, is expected to hydrolyze rapidly in humid air. 

Bulk agents included mustard (bis-2-chloroethyl sulfide, 12 tonnes), lewisite (2-chlorovinyl-dichloro arsine, 2.5 tonnes) and nerve agents in the G- and V-classes (0.3 tonne). The scrap (400 tonnes) consisted mainly of several thousand empty, mustard-contaminated 210 drums and ordnance casings stored in open pits. All of the lewisite and some of the mustard and nerve agents were stored in 1 ton containers. Nerve agents were also stored in non-explosive ordnance, primarily 105 and 155 mm artillery shells. Mustard which had aged or had been thickened with polymers was also contained in non-explosive ordnance. The waste previously had been sorted by type, collected and stored at four remote, protected sites on the EPG. 

Overview Chemical agents other than mustard were destroyed by neutralization prior to incinerating or otherwise disposing of the generated secondary waste. Mustard in all forms was destroyed by direct incineration. This was the only practical choice where the agent had aged to an intractable solid or had been thickened with polymers. 

Aged and thickened mustard (9 tonnes) contained in nonexplosive ordnance items was destroyed following approval of the test bum results. Ordnance was punctured with small explosive perforating charges under cold conditions, sealed with adsorbent (vermiculite) in cardboard boxes and incinerated. The clean ordnance items were recovered from the ash discharge system and sold to a foundry for melting into recyclable metal. 

Naturally, there are wide variations in the requirements of any specific colloidal function. For example, starch is employed as a thickening agent to provide a smooth creamy texture to the following products gravy, cream soups, sauces, chop suey, Harvard beets, salad dressings, prepared mustard, cream pie fillings, fruit pie fillings, pork and beans, cream-style corn, and baby foods. 

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