A blister agent is a chemical warfare agent that produces local irritation and damage to the skin and mucous membranes, pain and injury to the eyes, reddening and blistering of the skin, and when inhaled, damage to the respiratory tract. Blister agents include mustards (HD, HN, HQ, HT, and Q), arsenicals like lewisite (L), and mustard and lewisite mixtures (HL). Blister agents are also called vesicants or vesicant agents.^[121,122]

The deposit, absorption, or adsorption of chemical agents on or by structures, areas, personnel, or objects.^[123]

A chemical warfare agent is a chemical substance used in military operations to kill, seriously injure, or incapacitate through its physiological effects. Excluded are riot control agents, herbicides, smoke, and flame. Included are blood, nerve, blister, choking, and incapacitating agents.^[124]

A riot control agent
Chemical Name: O-chlorobenzylidene malononitrile^[125]

Detection paper works because certain dyes are soluble in chemical warfare agents. Normally, two dyes and one pH indicator are mixed with cellulose fibers in a paper without special coloring (unbleached). When the paper absorbs a drop of chemical warfare agent, it dissolves one of the pigments. Mustard agent dissolves a red dye and nerve agent a yellow dye. In addition, VX nerve agent causes the indicator to turn to blue—which, together with the yellow, will become green or green-black. Detection paper can thus be used to distinguish between three different types of chemical warfare agents. A disadvantage with the papers is that many other substances can also dissolve the pigments. Consequently, detection papers should not be located in places where drops of solvent, fat, oil, or fuel can fall on them. Drops of water cause no reaction.^[126]

The Fox is a six-wheeled, light armored vehicle designed primarily for reconnaissance of liquid chemical warfare agent hazards. On-board chemical warfare agent detection capabilities include the MM-1 mobile mass spectrometer, which is the primary detection device, the M43A1 chemical agent detector, which is an integral component of the M8 alarm system, and the M256A1 chemical agent detector kit. The Fox is also equipped with two radiation detectors. The Fox does not provide any biological warfare agent detection capability, but it does protect the crew from biological hazards, and it allows the crew to mark areas of potential hazard and safely take samples for laboratories to analyze for biological hazards.^[127]

A blister agent known as distilled mustard
Chemical name: Bis-(2-chloroethyl) sulfide^[128]

A blister agent known as sulfur-mustard/sesqui-mustard
Chemical names: HD: Bis-(2-chloroethyl) sulfide
Q: 1,2-Bis (2-chloroethylthio) ethane^[129]

A blister agent known as lewisite
Chemical Name: Dichloro-(2-chlorovinyl)arsine^[130]

In the field, the M256-series chemical warfare agent detector kit is simply referred to as the M256 kit. The M256 kit is a portable, expendable item capable of detecting and identifying hazardous concentrations of blister, blood, and nerve agents. The M256 kit is used after a chemical warfare agent warning to test for and confirm the presence and type of chemical warfare agent, and to determine if it is safe to unmask. The M256A1 kit has replaced the M256 kit. The only difference between the two kits is that the M256A1 kit will detect lower levels of nerve agent. US forces used both the M256 kit and the M256A1 kit during the Gulf War.

Some smokes, high temperatures, standard US decontamination solution number two (DS2), and petroleum products may cause false readings. Results may be inaccurate when sampling is performed in smoke from burning debris.^[131]

Mission oriented protective posture (MOPP) is a flexible system used to direct the wearing of chemical protective garments and mask—a system that balances mission requirements with the chemical warfare agent threat. Wearing chemical protective garments and mask provides soldiers protection against most known chemical warfare agents, biological agents, and toxins.

At MOPP Level 0 soldiers carry their protective mask while their remaining MOPP gear must be readily available (e.g., within the work area, fighting position, living space, etc.) At MOPP Level 1, soldiers wear their overgarment and carry the rest of their MOPP gear. At MOPP Level 2, soldiers wear their overgarment and overboots while carrying the mask with hood and gloves. At MOPP Level 3, soldiers wear their overgarment, overboots, and mask with hood, but not the gloves. At MOPP Level 4, soldiers wear all their MOPP gear.^[132] Commanders can raise or lower the amount of protection through five levels of MOPP. In addition, commanders, under certain situations, can exercise a mask-only option.^[133]

A liquid or dust-like compound that remains hazardous for hours, days or, in exceptional cases, weeks or more. It can be both a surface contact hazard or an airborne (vapor or particle) hazard. It can be picked up on a surface and might not be removed through decontamination; it can be spread to noncontaminated areas retaining its original lethality.^[134]

The MM-1 mobile mass spectrometer is the primary chemical warfare agent detector in the Fox reconnaissance vehicle. During Operation Desert Storm, the MM-1 monitored against a target list of approximately ten selected chemical warfare agents most likely to be present, based on intelligence reports of the suspected chemical warfare agent threat. To speed the initial search, the sampling probe operates at 180� C and the MM-1 looks for only four ion peaks of each detected chemical warfare agent and attempts to match the target list of chemicals against the pattern and ratio of these peaks. If an initial match is made with these four ion peaks at a pre-determined intensity and relationship, the MM-1 sounds an alarm. However, this first alarm does not confirm the presence of a chemical warfare agent, since there are many chemicals that have similar ion peaks and many combinations of chemicals that may yield ion patterns similar to those in the target list. Consequently, the MM-1 can falsely indicate the presence of dangerous chemical warfare agents. To more conclusively determine what chemical is present, the operator must lower the sampling probe temperature to 120� C, re-acquire a sample of the suspected substance, and run a spectrum analysis with the MM-1 against all the detection algorithms stored in the MM-1 chemical library. For more detailed analysis later, the complete ion spectrum of the suspected sample can be printed on a paper tape.^[135]

A riot control agent is a chemical that produces transient effects that disappear within minutes after exposure and rarely require medical treatment. Riot control agents are effective in quelling civil disturbances and in some military operations, in preventing unnecessary loss of life.^[136]

A temporary grouping of units, under one commander, formed to carry out a specific operation or mission; a semi-permanent organization of units, under one commander, formed to carry out a continuing specific task; or a component of a fleet organized by the commander of a task fleet or higher authority to accomplish a specific task or tasks.^[137]