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Assessing Chemical Exposure: A Lab Perspective

Assessing Chemical Exposure: A Lab Perspective. Kevin Chao, Ph.D. Department of Public Health State of California. Topics Covered. Introduction to All Hazards Terrorism Chemical Terrorism Specifics Toxicology/Properties of likely agents Public Health/Laboratory response

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Assessing Chemical Exposure: A Lab Perspective

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  1. Assessing Chemical Exposure:A Lab Perspective Kevin Chao, Ph.D. Department of Public Health State of California

  2. Topics Covered • Introduction to All Hazards Terrorism • Chemical Terrorism Specifics • Toxicology/Properties of likely agents • Public Health/Laboratory response • Environmental and clinical sample collection • Environmental and clinical sample testing

  3. All Hazards? • Chemical • Biological • Radiological • Nuclear • Explosive

  4. Toxic Industrial Chemicals • Chlorine • Hydrogen Cyanide • Ammonia • Phosgene • Methyl Isocyanate

  5. Bhopal, India • December 3, 1984 • 40 Tons of MIC (methyl isocvanate) • 500,000 exposed (5-8 miles downwind) • 11,000 disabled • 3,800 dead

  6. Similar Chemical Incident in California? • Metam Sodium • Where did it happen? • Lucky or what?

  7. Comparative Toxicity(lethal dose)

  8. Highly Toxic AgentsDeveloped to Kill or Disable • Advantages: • Small amounts needed • Surreptitious use • Targeted use • Disadvantages: • “Harder” to obtain • Nations? • Cults? • Lunatics?

  9. Some Overt Exposure Scenarios • Blast, leak • Ventilation ducts • Closed spaces: • subway cars • planes • Vehicular releases: • drive-by • crop dusting

  10. Some Covert Exposure Scenarios • Food, tobacco, alcohol • Medications, blood products • Cosmetics and personal hygiene products • Surfaces (door knobs, utensils): hand-to-mouth • Fixed distribution systems: water, natural gas

  11. Respiratory Irritant Gases • Chlorine • Phosgene • Oxides of nitrogen • Ammonia • Hydrogen chloride • Formaldehyde • Acrolein

  12. Respiratory Irritant Gases • Direct chemical reaction with tissues • pH, redox, addition, substitution reactions • structural lipids and proteins denatured or degraded • Induced inflammatory reaction

  13. Metabolic Toxicants • Cyanides • Azides • Sulfides • Carbon monoxide • Fluoroacetates • Dinitrophenol, pentachlorophenol • Many others

  14. Cyanide: ToxicologicalMode of Action • Blocks electron transport in mitochondria • Binds to Fe+3 in cytochrome oxidase • Prevents electron transfer to oxygen • Oxygen-rich red venous blood

  15. Carbon Monoxide • #1 chemical cause of acute toxic death • #2 rank air pollutant after CO2 • Vehicular, coal/oil burning, industrial • Invisible, odorless • Affinity for Hgb 220x greater than that of O2 • Forms carboxyhemoglobin • Proportionately decreases oxygen carrying capacity • Red venous blood

  16. Vesicant Agents(Blister Agents) • Mustard agents • Sulfur (military use) • Nitrogen (chemotherapy) • Lewisite (2-chlorovinyl dichloroarsine)

  17. Mustard: Targets

  18. Nerve Agents • A family of agents that kill by destroying acetyl cholinesterase, an enzyme essential for proper nerve function

  19. Physical Properties • Liquids at room temperature - not gases • Soluble in fat and water • Absorbed through respiratory tract, skin, eyes • Phosphonate esters • Tabun (GA) - most unavailable • Sarin (GB) - most volatile • Soman (GD) - fastest “aging” • VX - most potent and persistent • Other nerve agents

  20. Symptoms of Nerve Agents • “DUMBELS” • D - Diarrhea • U - Urination • M - Miosis • B - Bronchoconstriction, Bronchorrhea • E - Emesis • L - Lacrimation • S - Salivation

  21. What plant is this?

  22. Public Health Aimsin a Chemical Event • Identify the agent or cause • Circumstance, intelligence, clinical syndrome • Environmental or biological fluids assay • Determine temporal or geographical distribution of exposure • Determine relative (high/low) exposures

  23. Public Health Aimsin a Chemical Event (cont.) • Evaluate health implications • Provide medical and public health guidance and support • Provide continued surveillance and prevention

  24. After a CT IncidentEnvironmental Samples: • Identify chemical agent on scene • Define contamination zone • Check for effective decontamination • Determine when to allow re-entry

  25. Who collects the environmental samples? • Hazmat Team • CST Team, request through State OES • FBI Team • Standard procedures for collecting these samples as described in HAZMAT handbook with proper PPE and precaution

  26. What types of samples are needed? • Sample types: solid, liquid, wipes and air

  27. Who is going to test them for you? • Agencies may test them for you: • -Cal EPA (DTSC) • -US EPA • -LLNL for warfare agents • -CDHS could also help

  28. After a CT IncidentClinical Samples: • Confirm agent ID • Assist in medical treatment • Separate exposed from “Worried Well” • Support health effect studies

  29. Continues: • Predicting levels of toxicants in people using environmental monitoring is very difficult and includes many assumptions…

  30. Bio-monitoring- MeasuringChemicals in People • California has the funding to start a bio-monitoring program as a tool to assess human exposure to toxic chemicals in California

  31. Your Plan for Human Specimens • Local HAZMAT/first responders identify or suspect incident • Jurisdiction or FBI notifies CDHS/CDC

  32. Who collects the clinical samples? • Attending physicians at ED to order the collection of clinical specimens (three purple, one green and 25 cc urine for adults; urine only for infants and young children) to be collected • PH Labs as a hub to collect and ship initial samples to CDHS/CDC pending discussion

  33. What does CDC do with the first 40 samples? • CDC performs PCR and “Rapid Toxic Screen” on initial samples • CDC provides guidance to LRN for analysis of remaining samples

  34. Rapid Toxic Screen • Analysis of 40 samples for 150 agents or metabolites within 36 hrs • CDC has greater “screening” capability than currently available at any city or state public health lab

  35. Collecting Clinical Specimens: • Protocols for collecting and shipping blood (3 purple and 1 green) and urine (25 mL) (2 blank tubes and cups are required) posted on CDC’s website: http://www.bt.cdc.gov/labissues/ pdf/chemspecimencollection.pdf

  36. Collecting Clinical Specimens: • Clinical specimens will be collected at hospitals • Local Public Health Lab should continue train hospital staff (ED nurse managers especially) on what clinical samples should be collected.

  37. Call Kevin Chao for resources may be able to test the samples at 510-377-3435.

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