Nerve agents are toxic in the range of 10-20 micrograms/kg. This means a small drop of 1 microliter, about the size of the head of a pin, is sufficient to kill a person. VX is more dangerous because its lower volatility allows it to remain on the skin longer. In fact, most nerve agents have boiling points above 300° C, and are more like oils than volatile liquids. This means that the main risk is from skin contact, not inhalation.

Modern nerve `gases' are often binary agents, which contain two relatively benign chemicals that react to become lethal only when mixed together. An example is Novichok ("newcomer") agent, which is a particular threat because it can be synthesized from ordinary agricultural and industrial chemicals, and is 5-10 times more toxic than VX. The U.S. produced binary versions of standard nerve agents, which were designated by appending "2" to the name (e.g., GB-2, GD-2 and VX-2 were the binary forms of GB, GD and VX). VX is formed when QL and a harmless powder are mixed.

The first effect of mild exposure to organophosphate vapor is involuntary blushing. One's face feels hot and turns red as if embarrassed. Runny nose, miosis ("constriction" of the pupils of the eye to a small dot), salivation and chest tightness also occur. The next symptom, which may occur several hours later, is extreme mental excitement, i.e. uncontrolled racing thoughts caused by excess neuronal activity in the brain. It is essential for the victim to remain calm and try to slow their brain as much as possible. Nightmares occur if the victim tries to sleep. Overstimulation of the brain by organophosphates can cause neuronal cell death, resulting in permanent brain damage.

Skin contact of nerve agent causes fasciculations or twitching of the muscles near the point of exposure.

Stronger exposure must be treated immediately with atropine to prevent death. Researchers who use organophosphates in the laboratory are required to have a medical doctor in the same room holding two AtroPen syringes filled with atropine. These are pen-shaped single-use syringes (autoinjectors) which automatically inject the antidote when jammed against the victim's thigh through the clothing. They are designed to avoid the necessity of uncapping a needle or fumbling with the plunger of a syringe. If an accident occurs, the physician first injects him/herself with one syringe, then if still alive, the physician injects the researcher with the other one. Atropine blocks acetylcholine receptors, counteracting the effect of excess ACh. In the past, tiny amounts of atropine were used as the active ingredient in Contac cold medicine. The amount of atropine in these syringes (1-2 mg) would act as a potent sedative, but a single injection of atropine would probably not be fatal to an unexposed healthy adult person. In the event of an exposure to nerve agent, larger doses of up to 20-40 mg atropine may be necessary. These doses are much lower than the doses used to treat poisoning from organophosphorus insecticides. Pyridostigmine bromide and other reversible cholinergic antagonists can be used as protective agents against soman and tabun but are ineffective against sarin and VX.

The hazards of atropine autoinjectors were shown in the Gulf War. Despite the fact that no nerve gas was released by the Scud missiles, 230 Israelis were hospitalized from overdoses caused by inappropriate administration of atropine, and 8 deaths were caused by suffocation in gas masks.

In contrast to the way nerve gas situations depicted in the movies, you are not supposed to inject atropine directly into your heart. Also, unlike in the movies, nerve gas does not dissolve your flesh or cause you to scream in agony. And it's not green in color.

A second drug used in the treatment of nerve gas poisoning is pralidoxime chloride (2-PAM Cl), also known as Protopam. It is used to reactivate the acetylcholinesterase that is bound by the nerve agent. PAM is an oxime compound that inactivates the organophosphorus-esterase complex. As this complex ages over time due to dealkylation, it loses its susceptibility to PAM. Because the soman (GD) complex ages very rapidly, PAM is not effective against Soman (GD) poisoning. The dosage for PAM is normally 600 mg per injection; multiple injections may be required. PAM may also be given as 1 gram intravenously over an eight hour period. PAM does not cross the blood-brain barrier and cannot reverse the CNS effects of nerve agents.

Diazepam or other tranquilizers are frequently also used to reduce CNS overstimulation and seizures.

Some of the symptoms commonly associated with acute exposure to chemical nerve agents include miosis, frontal headaches, eye pain on focusing, slight dimness of vision, occasional nausea and vomiting, runny nose, tightness in chest, sometimes with prolonged wheezing, expiration suggestive of bronchoconstriction or increased secretion and coughing. Following systemic absorption, typical symptoms are: tightness in chest, wheezing, anorexia, nausea, vomiting, abdominal cramps, epigastric and substernal tightness, heartburn, diarrhea, involuntary defecation, increased sweating, increased salivation, increased tearing, slight bradycardia, miosis, blurring vision, urinary urgency and frequency, fatigue, mild weakness, muscular twitching, cramps, generalized weakness, including muscles of respiration, with dyspnea and cyanosis, pallor and occasional elevation of blood pressure; giddiness, tension, anxiety, jitteriness, restlessness, emotional lability, excessive dreaming, insomnia, nightmares, headaches, tremors, withdrawal and depression; bursts of slow waves of elevated voltage in EEG (especially on over ventilation), drowsiness, difficulty concentrating, slowness on recall, confusion, slurred speech, ataxia, coma (with absence of reflexes), Cheyne-Stokes respirations, convulsions, depression of the respiratory and circulatory centers, with dyspnea, cyanosis and fall in blood pressure.

Protection Nerve gas is a liquid that would be dispersed as a vapor or aerosol. Gas masks would provide some protection to individuals who need to cross contaminated areas or floors to escape, but would be of less value in a subway car because the victim would only have a few seconds to deduce that an attack is underway.

Depending on the agent and mode of dispersal, cutaneous absorption might also make the gas mask irrelevant. Nerve gas both in liquid and vapor form is easily absorbed through the skin, and will readily penetrate latex gloves. Persons in contaminated areas should avoid touching any object or surface, and never touch or move any suspected victim of a chemical attack, even with gloves. All twelve persons that died in the Tokyo subway attack came into contact with the liquid. Sarin, the most volatile nerve agent, is odorless; tabun has a sweetish or fruity smell. VX intoxication has a slower onset than other organophosphates, but is more toxic, and is less soluble in water. VX has a low volatility (it is 2200 times less volatile than sarin) and is thus more difficult for terrorists to use because it must be delivered as an aerosol. Its proposed military use was to deny physical access to territory.

Protection Sealed biohazard suits are the only protection. If an attack is imminent, go to a sealed room where all air is filtered through a filter containing sodium hydroxide or DS2 (2% sodium hydroxide, 70% diethylene triamine, and 28% ethylene glycol monomethyl ether). Basic solutions such as washing soda and lye dissolved in water react with the nerve gas, inactivating it.