I have seen scattered reports of people suspecting mustard gas is being used. While I to some degree doubt it based on the descriptions (I suspect some sort of anaesthetic gas). I decided I would provide as much general information as I could about mustard gas. Category: Blister Agent and strongly cytotoxic compounds. Effects: Causes large fluid to gel filled blisters on the skin: Dumping of chemical weapons - dailypress.com (See an image of an example from accidental exposure here). Warning the picture is pretty nasty, atleast to me. About the compounds: There are atleast TWO families of mustard gas commonly used. Nitrogen Mustard and Sulfur Mustard. The more commonly used compound is the thioether or sulfur mustard. THese compounds consist of a sulfur atom with two alkyl groups attached usually an ethyl group or substituted ethyl group with a cholrine atom at each end. ie.Cl-CH2-CH2-S-CH2-CH-Cl. Another commone one used is bis[2-(2-chloroethylthio)ethyl] ether. Which has the structures, Cl-CH2-CH2-S-CH2-CH2-O-CH2-CH2-S-CH2-CH2-Cl. As you can see though, the functional species consists of L-CH2-CH2-B. Where L is ANY leaving group such as Cl, Br, I, etc. and B is any lewis basic of sufficient strength. For example, sulfur is sufficiently lewis basic enough to do a nucleophilic attack (Sn2 type) on the leaving group (Cl). This creates a cyclic sulfonium (positively charges sulfur) compound and Cl- ion. This Cl- ion in water can go on to form hydrochloric acid. The sulfonium ion in the body gets attacked by the guanine in DNA, causing irreversible damage and often times cell death. Nitrogen mustards on the other hand are non-specific in their DNA reactions, the cyclic Nitronium ion (aka Amonium) is attacked my MANY different residues. All having similar results of cell death etc. The various types of mustard agents (and some other blister agents) ALL follow this same format as I showed above. Either by replacing the S with another element such as N or bonding two together etc. Now the bad news. There isn't much you can do to fight it. Despite it's structure, it tends to be more fat soluble than water soluble. This means it rapidly absorbs in the skin etc. The traditional methods of destroying it involved high concentrations of bleach etc. Peroxy acids are also used. I could see a range of methods to fight it if it is in the uncyclized stage, but once it is cyclized that is coing to be pretty tough to take out. I hope others can contribute more information to this.