The Increasing Threat of Agricultural Chemicals

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The Increasing Threat of Agricultural Chemicals

• Dave Reed, PhD
• Chemical Security Analysis Center
• Jan Moser, DVM, PhD
• Battelle Contractor in Support of the Chemical
  Security Analysis Center

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Chemical Terrorism Risk AssessmentA Method For
Assessing Pesticide Risk
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Why Bother?

• Required by Homeland Security Presidential
  Directive (HSPD) 18 Medical Countermeasures
  against Weapons of Mass Destruction
• 14 (c)
• The Secretary of Homeland Security shall
  develop a strategic, integrated all-CBRN risk
  assessment that integrates the findings of the
  intelligence and law enforcement communities with
  input from the scientific, medical, and public
  health communities.  Not later than June 1, 2008,
  the Secretary of Homeland Security shall submit a
  report to the President

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Why Bother?

• The U.S. needs a long term, risk based, strategy
  for chemical threat.
• Too often the chemical du jour is based on
  threat, vulnerability, or (not and) hazard
  combined with current news.

• The following are usually not connected when
  discussing chemical terrorism
• The science of chemicals and human exposure
• Terrorist capabilities and intent
• The possibilities for different actions
• The potential for medical responses and
  mitigation
• The uncertainty of all of the above.

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Given A Why Whats The How?

• Each section represents a significant data
  collection/generation effort. Without exception,
  these efforts include interagency coordination.

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How? - Chemical List

• CTRA chemical list generation was a separate
  activity considering 7 Federal and international
  lists with over 10,000 chemicals.

• Considered chemical warfare agents, toxic
  industrial chemicals, pesticides, selected
  pharmaceuticals.
• Decision criteria included toxicity, historical
  use, availability and ease of synthesis.
• 60 high priority chemicals being examined in 1st
  CTRA (Nov. 2007).
• Additional chemicals to be addressed in 2nd CTRA
  (Nov. 2009).
• Follows the framework of the Biological Terrorism
  Risk Assessment (BTRA).
• Provided as the chemical input to the iCBRN risk
  assessment.

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How? - Chemical List - Pesticides

• CTRA List
• 32 TICs
• 14 CWAs
• 10 Pesticides
• 1 Pharmaceutical

• Pesticides
• Brodifacoum
• Chlorfenvinphos
• Chlorpyrifos
• Dicrotophose
• Diphacinone

• Methamidophos
• Parathion
• Phorate
• Phosphamidon
• TETS

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How? - Threat Distribution

• Initiating Frequencies
• Four Groups International, State Sponsored,
  Domestic, Individual
• Groups characterized by technical resources and
  funding.
• Target Types
• Generic categories with surrogates for specific
  modeling and definition

• Inhalation large open small large divided
  large outdoor
• Ingestion water, food
• Dermal contact.
• Selection Probabilities (chemical, target).
• Production/Acquisition
• Production, purchase, theft, sabotage (sabotage
  scenarios provide their own source of
  chemicals).
• Performed as an event tree.

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How? - Attack

• Exposure estimates through specific surrogate
  models that represent each target. Ex Outdoor
  inhalation contains 15 dissemination modes.
• Fatality estimates from toxicity data combined
  with exposure to determine fatalities.
• Non-fatal casualties determined from fatality
  estimates.

• Consequence Modeling
• Outdoor Inhalation HPAC
• Indoor inhalation Well-mixed model
  mechanistically identical to CONTAM)
• Water Custom developed (Compares favorably with
  EPAs Pipeline.Net)
• Food Custom developed
• Dermal HPAC for ag. Sprays custom developed for
  surface contamination.

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How? - Mitigation

• Medical Mitigation
• Impact of countermeasures
• Availability
• Efficacy/Effectiveness
• Time to detection, symptom and response.
• Critical healthcare equipment
• Availability
• Potential substitutes.
• Module developed jointly with HHS.

• Event Timelines
• Identification determines the time delay to
  medical mitigation
• 3 event types
• Event recognized as terrorist act (dissemination
  mode dependant)
• Chemical detected by monitor
• No detection medical mitigation depends on
  timing of clinical diagnosis.

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How? Determining Risk

• Risk Calculations
• Distributions are used to capture the
  uncertainty
• Essentially every value in the CTRA risk engine
• has an associated uncertainty
• Computationally processed as via Latin Hypercube
• sampling to generate the risk curves
• Risk curves are summarized and presented as box
• and whisker plots.

Consequence (Fatalities)
Consequence
(Fatalities)
Chemical Threat Agents
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So What Do We Get?

• Absolute risk values in terms of frequency of
  occurrence (probability of event) and
  consequences (fatality and/or injury).
• Parameter Sensitivity
• What if helping guide policy makers
• What if substance X is known to be of high
  interest to adversaries (threat)?
• What if we have to allocate resources to focus on
  malls or stadiums (attack)?
• What if the countermeasures were more widely
  available/effective (mitigation)?
• Knowledge Gaps
• Identify gaps/holes in the existing data.

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The Threat of Pesticides
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Historical Perspective
The first known pesticide was elemental sulfur
dusting used in Samaria about 4,500 years ago.
By the 15th century, toxic chemicals such as
arsenic, mercury and lead were being applied to
crops to kill pests.
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Historical Perspective
In the 17th century, nicotine sulfate was
extracted from tobacco leaves and used as an
insecticide.

• Two more pesticides were introduced in the 19th
  century, pyrethrum which is derived from
  chrysanthemums, and rotenone which is derived
  from the roots of tropical vegetables.

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The Modern Era

• 1900-1940 Pesticide use limited to inorganic
  chemicals and natural products of plant origin
• Arsenicals
• Strychnine
• Pyrethrum
• 1940-1970 Rapid development and widespread use
  of many new synthetic pesticides, including very
  persistent chlorinated hydrocarbons
• DDT
• Chlordane
• Aldrin
• 1980-present Replacement of chlorinated
  pesticides with organophosphorus pesticides
• Malathion
• Parathion
• Disulfoton

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Uses of Pesticides Major Classes
Acaricides
Insecticides
TEPP
Fungicides
Dichlorvos
Molluscides
Edifenphos
Nematocides
Clonitralid
Rodenticides
Oligomycin A
Herbicides
Roundup
Phosacetim
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Pesticide Uses

• Contributions
• Control certain vector-borne diseases (malaria,
  typhus, plague, yellow fever) to save millions of
  lives
• Increased production of food and fiber
• Protection of many materials during storage
• Concerns
• Organophosphorous pesticides structurally similar
  to chemical warfare nerve agents
• Potential use of common and easily accessible
  pesticides in chemical terrorism
• Accidental release of pesticide or toxic reagents
  in quantities detrimental to human health and/or
  long-term environmental contamination

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1984 Bhopal Disaster - India

• Accidental release of methyl isocyanate from the
  Union Carbide pesticide plant in Bhopal, India
• Ideal conditions
• Cool, calm weather
• Night time, everyone asleep, no warning
• Heavily populated area
• Shanty housing provided no protection
• Geography funneled dense gas
• Sabotage disgruntled employee intentionally
  mixed in water to spoil tank of methyl isocyanate
• 200,000 to 300,000 experienced symptoms
• 11,000 serious casualties
• Over 3800 fatalities

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The Chemical Threat Spectrum

• Chemical warfare agents (CWAs)
• Chemical warfare nerve agents originally
  developed as organophosphorous pesticides
• Nearly impossible to obtain, must be synthesized
  by terrorists
• Nerve agents (G, V) - Have seen previous
  terrorist use
• Nitrogen and Sulfur Mustards (H, HN, HD)
• Organophosphorus and Chlorinated Pesticides
• A number of very toxic compounds
• Easily obtained
• Toxic industrial chemicals (TICs)
• Large array of materials - Chlorine, Ammonia,
  Acids, Bleach
• Reasonably accessible - Produced in millions of
  tons annually
• Accidents have the capacity to cause a
  catastrophic number of casualties (Bhopal)

Toxicity Increases
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Threat Materials
Nerve Agents (CWA)
Blister Agents (CWA)
Arsenicals
Mustards S and N
G-Agents
V-Agents
GB
Sulfur Mustard
VX
Lewisite
Blood Agents (TICs)
Pulmonary Agents (TICs)
Hydrogen Cyanide
Phosgene
GABA Antagonists
Pesticides (TICs)
Amiton
TETS
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Examples of Toxic Pesticides that are or have
been available in the U.S.
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Regulation and Synthesis
Unclassified

• Regulation
• Environmental Protection Agency (EPA)
• Department of Transportation (DOT)
• Synthesis
• Synthetic routes are simple, straightforward, and
  most are in public domain
• All reagents commercially available in large
  quantities
• Technology and many reagents used to prepare
  organophosphorous pesticides also used to prepare
  nerve agents
• Education and skill level required to produce
  pesticides comparable to that of nerve agents
• More stringent environmental controls and safety
  precautions distinguish production of nerve
  agents from that of organophosphorous pesticides

Unclassified
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Example of Synthetic Route

• The final step in the preparation of DFP and the
  nerve agent sarin (GB) are identical

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Production Equipment

• Similar to that used to produce most other
  industrial chemicals
• Provides opportunity to covertly produce
  pesticides or nerve agents

A 75 lb reactor installed in a small-scale
process laboratory
A typical 950 lb reactor in a large-scale
production facility
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Physical Properties
Unclassified
Unclassified
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Mechanisms of Action
Unclassified

• Organophosphorous Pesticides
• Mechanism of action same as that of nerve agents
• Inhibit acetylcholinesterase, the enzyme
  responsible for the destruction of the
  neurotransmitter acetylcholine
• Accumulation of acetylcholine causes
  uncontrollable stimulation of nerve cells
• Affects central and peripheral nervous systems
• Elicit their toxicity in both insects and mammals
• Organochlorine Pesticides
• Chlorinated cyclodienes, such as endosulfan,
• block action of the neurotransmitter GABA,
  the
• primary inhibitory neurotransmitter in the
  brain
• More localized in the central nervous system
• Leads to nervous system hyperexcitability

Unclassified
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ToxicologyOrganophosphorus Pesticides
Unclassified
Unclassified
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Toxicology
Unclassified

• Organophosphorous Pesticides
• Generally much less toxic than chemical warfare
  nerve agents
• Death with heavy exposure usually related to
  respiratory collapse
• Have potential to be much more acutely toxic than
  organochlorines
• Organochlorine Pesticides
• Signs and symptoms primarily associated with
  central nervous system stimulation
• Headache, nausea, dizziness, hyperexcitability,
  hyperreflexia
• Life-threatening effects result from the
  development of seizures - tremor, convulsions,
  coma, respiratory distress, and death

Unclassified
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Dissemination
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Environmental Persistence
Unclassified

• Organophosphorous Pesticides
• Degraded by hydrolysis, yielding non-toxic water
  soluble products
• Toxic hazard is short-term, less environmentally
  persistent than organochlorines
• Organochlorine Pesticides
• Persistent low volatility, chemical stability,
  slow rate of biotransformation and degradation
• Bioaccumulate in tissues of plants and animals
• Widespread environmental contamination
• Most are banned or severely restricted in the
  U.S. but continue to be used extensively in
  developing countries

Unclassified
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Impact of Contamination with Persistent Chemicals

• Persistent chemicals may be
• Environmentally stable (VX nerve agent,
  organochlorine pesticides)
• Stored within another substance such as paint or
  plaster to later leach out from the surface
• Primary danger of persistent chemicals is the
  potential to contaminate individuals over a
  prolonged period of time
• Because of this danger, persistent chemicals can
• Deny the use of existing infrastructure, causing
  economic loss
• Prevent the use of raw materials, industrial
  assets, and finished goods
• Prevent the use of public services such as
  transportation assets, municipal buildings, and
  recreational facilities
• Decontamination and restoration are necessary
  before infrastructure is habitable

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Unclassified
Countermeasures

• Medical Countermeasures
• Organophosphates
• - Atropine reversibly blocks acetylcholine from
  acting at receptor sites on target cells
• - Pralidoxime chloride (2-PAM) reactivates
  acetylcholine esterase
• - Anticonvulsants (diazepam) controls seizures,
  decreases the risk of permanent brain damage
• Organochlorines
• - Anticonvulsants to control seizures
• - Supportive care
• Medical Challenges with mass casualty scenario
• - Without personal protective equipment (PPE),
• serious injury possible
• - Mass casualties likely to overwhelm medical
  capacity

Unclassified
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Unclassified
Countermeasures

• Protection for the General Population
• - Outdoors
• Evacuation upwind
• Overhead protection
• Indoor sheltering
• - Indoors
• Turn off air handling systems to avoid drawing
  pesticide into building
• Close and seal windows and exterior doors
• Protection for First Responders
• Must be protected from respiratory and dermal
  exposure
• Four levels of PPE, from complete isolation with
  maximum respiratory protection to normal work
  clothes without respirator or protective suit

Unclassified
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Countermeasures
Unclassified

• Personnel Decontamination
• Remove clothing, promptly shower with soap and
  water
• Flush eyes with copious amounts of water
• If ingested, pump stomach

Unclassified
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Environmental Cleanup
Unclassified

• Removal of pesticides is essential to eliminate
  hazards
• Containment and control
• Prevent from spreading with trenching, absorbent
  material, covering with and securing tarp, etc.
• Cleanup
• Carefully remove from area
• Remove contaminated soil three inches
• below wet surface line
• Decontamination
• Decon material depends on pesticide
• Organophosphates lye or lime
• Organochlorines cannot be deconned
• use detergent and water to remove
• Disposal
• If cannot be deconned, place in leakproof
  containers

Unclassified
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Summary

• Chemical incidents are real, both accidental and
  intentional
• Many chemical threat agents, such as pesticides,
  are easily synthesized and/or widely available
• Capable of causing tens of thousands of
  casualties
• CSAC Represents a One of a Kind Capability
  within the Department of Homeland
  Security/Interagencies
• Hazard Assessment
• ST Reachback
• Knowledge Management

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