NERVE AGENTS Nerve Gases

1
NERVE AGENTS (Nerve Gases)

• Lindsay Herendeen
• TOX
• Molecules of Death, Chapter 8

2
HISTORY

• Nerve Gases first developed for use in WWI
  Mustard Gas, Chlorine, Phosgene.
• Only Chlorine and Phosgene are gases at normal
  temperatures.
• Nerve gases were not utilized during WWII.
• 1988 Single greatest event since WWI Iraqi
  attack on Northern Iraq village of Halabja,
  killed 4000-7000 people.

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HISTORY

• Modern Nerve Agents more toxic
• Tabun (GA)
• Sarin (GB)
• Soman (GD)
• VX
• Tabun, Sarin, Soman discovered by Germany in late
  1930s, early 1940s VX discovered by England in
  1950s.
• Tabun (GA) Discovered by Gerhard Schrader while
  researching organophosphate insecticides.
• Sarin, Soman, VX Developed for purpose of
  Chemical Warfare.
• None are actually gases!

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SARIN (GB)

• Developed for purpose of Chemical Warfare.
• Schrader Ambrose Rudiger and van der Linde
• 1995 Japanese cult, Aum Shinrikyo
• Lunch boxes/drink containers with Sarin on Tokyo
  subway- killed 12, affected 500

5
VX

• Developed for purpose of Chemical Warfare.
• Greater toxicity via inhalation because can be
  delivered as a smoke.
• 1968 Utah, 6000 sheep killed when chemicals
  drift during test.
• 1994 Aum Shinrikyo killed own member trying to
  defect.

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DELIVERY

• Shells/Bombs
• Stored in two separate canisters until delivery
  for ease of transport and storage.
• Crop Sprayers

7
EXPOSURE

• Inhalation
• Droplet clouds
• Dermal Absorption
• Often mixed with thickening agent
• Highly dangerous to synthesize, high exposure
  rate.
• Health workers.

• Death can occur in lt1 minute.
• 2 weeks to recover from physical symptoms
• Several months to return to normal Acetylcholine
  Esterase levels.

8
SYMPTOMS

• Symptoms may vary depending on route of exposure
• miosis (narrowing of pupils), blurred vision,
  headache, runny nose, tightness of chest,
  difficulty breathing, drooling, excessive
  sweating, nausea, vomiting, cramps, involuntary
  urination and defecation, twitching, jerking,
  staggering, convulsions, confusion, drowsiness,
  coma, death
• Some cases may cause brain damage as agents can
  easily cross blood-brain barrier.

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COMPARATIVE LC50

• VX is most toxic of all 4 Nerve agents.
• As little as 1-10mg of a nerve gas may be enough
  to cause death in humans.

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MODE OF ACTION

• Same MOA as organophosphate insecticides.
• Acts on cholinergic system at neuromuscular
  junction.
• Bind to Acetylcholine Esterase rendering it
  ineffective.
• Constant firing muscle spasm

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PROPHYLACTIC

• Taken before exposure for preventative measures.
• PB Pyridostigmine bromide
• Pill form NAP (Nerve Agent Protection)
• Bind to some AChE nerve gas binds to rest PB is
  reversible liberates enough AChE to continue
  life processes.

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ANTIDOTES

• Dangerous, may have toxic effects.
• Developed for military uses.
• Mixture of 2 compounds Atropine Oxime
• Atropine Blocks ACh receptors
• Oxime removes nerve agent from Ach
• Pralidoxime and Dioximes/Obidoxime
• Problems with aging.
• Agents start to separate within 30 minutes of
  exposure and then antidote will not be effective.

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PREVENTION

• Protective Suit (Military Operational Protective
  Posture)
• Detectors
• Coloring
• Cyanide
• Infrared/Mass Spectrometer
• Phosphorus
• Complications

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CHEMICAL WEAPONS CONVENTION

• 1997
• Over 20 countries have nerve gas stockpiles
• US has 30,000 tons of gases, 16B to dispose
• Classifies chemical weapons 3 Schedules
• Nerve agents in first schedule
• No or low commercial use
• Must be completely disposed of by 2007
• 2004 80 of all chemicals destroyed by US
• US granted an extension, now projected date for
  complete destruction 2014

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DISPOSAL/DECONTAMINATION

• Decontamination
• Removal of nerve gases from ground, clothing,
  machinery
• Must be washed with bleach to instigate
  hydrolysis
• Use of Fullers earth, absorb and render
  ineffective
• Disposal
• Incineration
• Chemical Neutralization
• Hydrolysis, neutralize with acid, dilution,
  convert to solids

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COMPLICATIONS

• Nerve gases have similar properties to
  organophosphate insecticides and same effect as
  PB.
• Difficult to identify cases of nerve gas
  poisoning without confounding factors.
• Gulf War Syndrome