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Module 2Potential Exposure Routes and

Hazards

Module 2Potential Exposure Routes and

Hazards

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How Nerve Agents Work

• Nervous system controls normal functions through use of chemicals

• Chemicals act as instructions to nerves, muscles, and glands

• Two forms of instructions:– stimulate (move or work)– relax (stop or rest)

• Nerve agent interferes with normal transmission of instructions

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Leads to Destruction of System Control

• Over-stimulates nerve endings and central nervous system

• Causes muscles and certain glands to malfunction

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Normal Nervous System Function

• Nerve impulse transmitted

along nerve cells

• Acetylcholine (a neurotransmitter) is released

• Target cell is stimulated

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Normal Nervous System Function

• Once target cell is stimulated, acetycholine is deactivated by acetylcholinesterase

• Target cell relaxes

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Nerve Agent Interference

• Nerve agents inactivate acetylcholinesterase

• Excess acytelcholine accumulates

• Muscle action becomes uncontrolled and twitchy

• Muscle can tire and collapse

• Gland continues to secrete sweat, tears, or mucus

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Routes of Exposure

• Inhalation

• Ingestion

• Direct contact

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Inhalation

• Respiratory failure is the chief cause of death after severe exposure

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Direct Contact

• Absorption through skin:– All agents can be absorbed– VX persists longer– GB evaporates quickly, but

still a threat– Scrape or cut in skin allows

immediate entry

• Entry also through eyes

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Direct Contact

• Absorption through skin:– All agents can be absorbed– VX persists longer– GB evaporates quickly, but

still a threat– Scrape or cut in skin allows

immediate entry

• Entry also through eyes

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Ingestion

• Access to bloodstream via digestive system

• Effects similar to inhalation, but at greater doses

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Inhalation Exposure From Atmospheric Transport

• The critical route of exposure that you should be most concerned with is inhalation of agent vapors or aerosols

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How Vesicant Agents Work

• Chemical burns to skin – especially warm, moist surfaces

• Chemical burns to soft membranes– eyes– eye ball– lung tissue– mouth– throat

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Sulfur Mustard (HD) Agent Exposure

• Delayed reaction and little or no pain

• Blisters develop in 2 to 36 hours

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Routes of Exposure

• Inhalation

• Ingestion

• Direct contact

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Inhalation

• Can destroy mucous membrane lining of:– nasal passages – throat– bronchial tubes

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Direct contact With Liquid or Vapor

• Highly damaging to skin - especially warm, moist areas

• Mucous membranes are very susceptible to effects of blister agents including:– lining around eyelids– inside mouth and nose

• Sweat and moisture increase effect

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Ingestion

• If deposited on or in food items, drink, etc

• Injures warm, moist tissues of mouth, throat and esophagus

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Inhalation Exposure From Atmospheric Transport

• The critical route of exposure that you should be most concerned with is inhalation of agent vapors or aerosols