Sarin Gas

Sarin gas (O-Isopropyl methylphosphonofluoridate), also called GB, is one of the most dangerous and toxic chemicals known. It belongs to a class of chemical weapons known as nerve agents, all of which are organophosphates. The G nerve agents, including tabun, sarin, and soman, are all extremely toxic, but not very persistent in the environment. Pure sarin is a colorless and odorless gas, and since it is extremely volatile, can spread quickly through the air. A lethal dose of sarin is about 0.5 milligrams; it is approximately 500 times more deadly than cyanide.

Sarin, which has become infamous in contemporary times from its use in Iraq, and by the Aum Shinrikyo doomsday cult, was first synthesized in 1938 by a group of German scientists researching new pesticides. Its name is derived from the names of the chemists involved in its creation: Schrader, Ambros, Rudriger, and van der Linde. A pilot plant to study the use of sarin was built in Dyernfurth. Although they produced between 500 kg and 10 tons of sarin, the German government decided not to use chemical weapons in artillery during World War II. The Soviet army captured the plant at Dyernfurth at the end of the war and resumed production of sarin in 1946. The Russian government currently has about 11,700 tons of sarin.

Between about 1950 and 1956, the United States produced sarin. It is estimated to have stockpiles totaling 5,000 tons of the nerve agent stored in different parts of the country. Several other countries including Syria, Egypt, Iran, Libya, and North Korea have confirmed or suspected stocks of sarin.

Like other organophosphate nerve agents, sarin inhibits the break down of the enzyme acetyl-cholinesterase. Under normal conditions, this enzyme hydrolyzes the neurotransmitter acetylcholine. When sarin is present, the build up of acetyl-cholinesterase results in the accumulation of excessive concentrations of acetylcholine in nerve synapses. This overstimulates parasympathetic nerves in the smooth muscle of the eyes, respiratory tract, gastrointestinal tract, sweat glands, cardiac muscles, and blood vessels.

After exposure to sarin, symptoms begin within minutes. If a person survives for a few hours after exposure, he or she will likely recover from the poisoning. The first symptoms of sarin poisoning include a runny nose, blurred vision, sweating, and muscle twitches. Longer exposures result in tightness of the chest, headache, cramps, nausea, vomiting, involuntary defecation and urination, convulsions, coma, and respiratory arrest.

Atropine acts an antidote for nerve agent, including sarin. Atropine binds to one type of acetylcholine receptor on the post-synaptic nerve. A second antidote is pralidoxime iodide (PAM), which blocks sarin from binding to any free acetyl-cholinesterase. Both should be administered as soon as possible following exposure to the toxin. Diazapam can also be used to prevent seizures and convulsions.

SEE ALSO Toxicological analysis; Toxicology.