Vapor nerve agent

Structural firefighters protective clothing is recommended for fire situations only it is not effective in spill situations or release events. If chemical protective clothing is not available and it is necessary to rescue casualties from a contaminated area, then structural firefighters gear will provide very limited skin protection against nerve agent vapors. Contact with liquids, solids, and solutions should be avoided. 

Standard turnout gear with SCBA provides a first responder with sufficient protection from nerve agent vapor hazards inside interior or downwind areas of the hot zone to allow thirty minutes rescue time for known live victims. 

Personal Protective Equipment Standard turnout gear with SCBA provides a first responder with sufficient protection from nerve agent vapor hazards inside interior or downwind areas of the hot zone to allow thirty minutes rescue time for known live victims. Self-taped turnout gear with SCBA provides sufficient protection in an unknown nerve agent environment for a three-minute reconnaissance to search for living victims, (or a two-minute reconnaissance if mustard, blister agent (HD) is suspected). 

The G-agents are all viscous liquids of varying volatility (vapor density relative to air between 4.86 and 6.33) with faint odors ( faintly fruity , or spicy , odor of camphor ). Agent VX is an amber-colored hquid with a vapor density of 9.2, and is considered odorless. Thus, nerve agent vapors possess little to no olfactory warning properties (Table 6.1). 

TABLE 6.3. Acute inhalation lethality (LC50 LCtso) for nerve agent vapor in laboratory animals... 

The choice of appropriate treatment for nerve agent intoxication depends on the agent as well as extent and route(s) of exposure. Very mild exposure to nerve agent vapor may necessitate only decontamination and observation severe exposure to vapor or liquid requires immediate decontamination, antidote administration, artificial respiration, monitoring, and supportive therapy over hours to multiple days (ATSDR, 2007 Sidell, 1997 Vale et al, 2007 Pulley and Jones, 2008). Convenient triage classifications have been developed by ATSDR (2007) in collaboration with the US Army Medical Research Institute of Chemical Defense. 

Sekowski, J.W., Orehek, M. A., Bucher, J. et al. (2004). Low-level inhalation exposure to chemical nerve agent vapor induces expression of neuronal apoptosis and regeneration genes. Proceedings of the 24th Annual Army Science Conference, November 29-December 2, 2004, Orlando, FL. 

Rhinorrhea may precede miosis as the first indication of exposure to even small amounts of nerve agent vapor. After exposure to high concentrations/ doses by any route, rhinorrhea occurs as part of the generalized increase in secretions. Direct ocular contact to nerve agents may cause miosis, conjunctival injection, pain in or around the eyes, and dim or blurred vision. 

Toxic effects occur within seconds to 5 min of nerve agent vapor or aerosol inhalation. The muscarinic effects include ocular (miosis, conjunctival congestion, ciliary spasm), nasal discharge, respiratory (bronchoconstriction and increased bronchial secretion), gastrointestinal (anorexia, vomiting, abdominal cramps, and diarrhea), sweating, salivation, and cardiovascular (bradycardia and hypotension) effects. The nicotinic effects include muscular fa-sciculation and paralysis. CNS effects can include ataxia, confusion, loss of reflexes, slurred speech, coma, and paralysis. 

The initial effects of nerve agents depend on the dose and route of exposure. A small inhalation exposure from nerve agent vapor causes a response in the eyes, nose and airway, such as miosis, conjunctival injection, eye pain, rhinorrhea, bron-choconstriction, excessive bronchial secretions, and mild to moderate dyspnea (9,13,18). Larger exposures cause central nervous system effects within seconds to minutes, including loss of consciousness, seizures, and central apnea. Death can occur within 5-lOmin of a lethal dose, usually due to respiratory failure from the combined effects of respiratory muscle paralysis, loss of airway control and profuse bronchorrhea (13,14). 

A tight chest or shortness of breath is another typical complaint following exposure to small amounts of nerve agent vapor. Dyspnea (difficult or labored breath-... 

Small Areas Ventilation. In heavily contaminated areas, decontamination with copious amounts of aqueous sodium hydroxide solution (a nunimum of 10 percent by weight) may be required. If sodium hydroxide solution is not available, then sodium carbonate may be used. Removal of porous material, including painted surfaces, that may have absorbed Nerve Agent vapor may be required as these materials could continue to re-release vapor after exposure has ceased. 

M8A1 Alarm, M256A1 Kit, and CAM. However, since these agents have minimal vapor pressure, it may be difficult to effectively identify "V" series Nerve Agent vapors except in a confined or enclosed space. 

Miosis (pinpointing of pupils) and rhinorrhea (runny nose) may be the first indications of exposure to nerve agent vapor. Miosis is indicative of vapor exposure unless liquid has been in contact with the eyes. Difficulty breathing (shortness of breath or tightness of the chest) may also be present. Lethal amounts of vapor cause loss of consciousness and convulsions within 30 seconds to 2 minutes of exposure, followed by cessation of breathing and flaccid paralysis after several more minutes. 

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