Download Chemical Agents of Opportunity Final Test Answer Key and Rationale:

Chemical Agents of Opportunity Final Test Answer Key and Rationale:
1. Choice a) is correct. Ammonia is a high-production volume chemical that has significant toxicity in
readily available quantities. Anthrax is a Category A (CDC designation) biologic agent. Sarin is a highly
potent chemical weapon in the “nerve agent” category; although it is a member of the class of
organophosphorous compounds, but has no utility as an industrial compound. Mustard gas is a
chemical weapon within the “blister agent” category. It is also not used as an industrial compound.
Water is commonly used in industry, but as a chemical compound does not exert toxic effects in doses
that would be administered in an attack of HazMat incident.
2. Choice c) is correct. While all of the choices represent possible terrorist targets or methods, anything
that creates fear, particularly if requiring little effort or resulting in little risk to the terrorist (asymmetry),
may lead to immediate impaired functioning of components of society, or overwhelming of response
capabilities.
3. Choice c) is correct. TICs/TIMs are already in place or obtainable at little cost compared to most
typical chemical warfare agents. They are widely available in large quantities and often stored and
transported with little security. They are characterized by variable organ effects, but have significant
toxicity in relatively low doses. Vulnerability is present for both stored, in use, and transported
compounds.
4. Choice d) is correct. Wind direction is one of the environmental factors that can affect the outcome of a
release; however, it is not a factor in the hazard ranking of chemical compounds. This ranking is
comprised of information on the inherent toxicity of the chemical, the amount available to be released or
taken, the volatility – which will determine the inhalational toxicity, as well as the size of a resulting
chemical plume. Some ranking systems incorporate the history of prior use as a factor in determining the
potential hazard for future use.
5. Choice c) is correct. The ability to prevent and mitigate chemical releases requires a toxidrome-driven
approach to the recognition of chemical classes. Early, correct identification will allow proper
utilization of appropriate personal protective equipment and targeted requisitioning, delivery, and
utilization of countermeasures. Choice a) is only useful if responders can access internet-based tools at
the time of need and if they have correct information regarding the chemical of interest. Widely
available site-specific information is deemed a security risk that outweighs its informational value.
Choice b) is a good way to design drills and test response capability, but this should be done recognizing
that unusual agents can be obtained and deployed. Choice d) is inefficient and would result in
unintended injuries from inappropriate use.
6. Choice b) is correct. While encyclopedic knowledge of all chemicals is not possible, training in the
common physical effects of many chemical classes is possible. The majority of chemical events involve
a relatively small number of chemical classes (covered in this course). Interested and experienced
individuals should inform the legislative process; however, control of chemical transport-related risks
will be very difficult and will not address all TICs/TIMs-related vulnerabilities. Search and Recovery
training is part of some first responder training. While this is useful for many organizations, it is not
specific to chemical events.
7. Choice b) is correct. In this country, of the options provided, more compounds of potential terrorist use
would be found amongst the fertilizers, pesticides, and solvents in these stores than in grocery stores,
where choices would be more likely limited to lower concentrations of certain cleaning agents. While
the federal government and libraries provide access to information about many compounds with
significant toxicity, they are not a source of these items.
8. Choice b) is correct. Examples of all of these compounds have been provided in this course. The
entities in choice a) represent bio-agents (infectious organisms or infections). The items in choice c) and
d) are of low or no significant toxicity in readily deliverable amounts.
9. Choice a) is correct. In the balance of excitatory (stimulant compounds) and inhibitory (sedative
compounds) tone, enhanced inhibition is much more common than is reduced excitatory tone (choice d)
as a cause of coma. The other two choices would both lead to increased stimulation (e.g. agitation and
seizures) with inhibition of inhibitory tone (choice b) being the more common.
10. Choice b) is correct. Carfentanyl is a derivative of fentanyl with more than 10,000 times the potency of
morphine, resulting in profound respiratory and mental status depression in mcg doses. Diazepam is a
benzodiazepine or sedative agent that alone rarely causes death. Halothane is a general anesthetic that
some thought might be implicated in the Russian event, but was not the major agent.
11. Choice c) is correct. In sufficient doses, all sedative agents result in respiratory depression. Bleeding is
a feature of anticoagulant overdoses, while cardiac arrhythmia can be seen with a number of
hydrocarbons (some of which also cause central nervous system and respiratory depression) and
stimulants. Seizures are characteristic of the stimulants, as well as a number of other compounds, such
as tetramine and hydrazines.
12. Choice a) is correct. Supporting ventilation is the most important measure for patients presenting with
respiratory depression. Chest compressions are used in the absence of cardiac activity, while naloxone
reverses the respiratory depression caused by narcotics (opioid drugs) only. Oxygen supplementation is
not useful in the absence of adequate respiration.
13. Choice c) is correct. The premise of the Chemical Agents of Opportunity course is that widespread
availability of an inadequately secured quantity of chemical compounds will result in large scale
exposures. Prices are a function of resource utilization, supply, and demand. Price fluctuation or the
prominence of U.S. industry are not serious concerns regarding the number, amount or access to these
chemicals. While individual responsibility for safe storage is important in homes and the workplace, the
responsibility for control of large quantities in industry falls on chemical plants, the producers and users
of these compounds.
14. Choice d) is correct. Removal from a source of exposure is the initial priority, as it both reduces
ongoing exposure and prevents rescuer exposure. Decontamination, support of respiration, and cardiac
resuscitation are all important or essential elements of patient care, but not the initial priority on scene.
Notification of regulatory agencies is important for expanded response and resource purposes; but again,
not the main initial priority.
15. Choice d) is correct. AEGL3 is the most severe of the 3 levels for airborne concentrations, used for
planning purposes for airborne plumes. The Emergency Alert System (EAS) originated as the
Emergency Broadcast System and is used as a radio- and television-based alert system for messages of
public health or security importance. CERCLA (the Comprehensive Emergency Response,
Compensation, and Liability Act), also known as the Superfund Act, identifies priority sites and
chemical compounds for cleanup. The EPA’s Amendments to the Clean Air Act requirement that
companies create Risk Management Programs (RMP) when dealing with identified chemicals (such as
phosgene or 170 other priority toxic or flammable compounds) that are produced, used, stored or
transported.
16. Choice c) is correct. The most important characteristic predicting the site and timing of symptoms from
gas inhalation is water solubility, with water-soluble gases exhibiting upper airway irritant effects and
poor water- soluble gases resulting in lower airway symptoms with a concomitant delayed or absent
warning of the gas’ presence. Odor, flavor/taste, and color are all variable and poor predictors of toxic
symptoms; the best example being carbon monoxide, which is odorless, colorless, and tasteless.
17. Choice b) is correct. Anhydrous ammonia is a very high-production chemical and serves as a major
source of nitrogen for soil treatment. Anhydrous ammonia is a liquefied gas under pressure. Ammonia
in household window cleaner is present at a concentration of ~5-10%. Ammonia is a basic compound
(proton acceptor) forming NH4Cl in combination with water and acids. Ammonia can act as a very
weak acid, but this is not a feature of its cellular injury process.
18. Choice d) is correct. As always, dose in significant exposures (inhalation or otherwise) determines
toxicity. Inhaled dose is determined not only by concentration, but also by length of time the compound
is inhaled. The patient age and length of time to treatment may welll impact the clinical effect of a given
dose
19. Choice a) is correct. Methylene chloride is a solvent used as a paint stripper; it is metabolized to
carbon monoxide by the liver. The other three agents are used as soil and structural fumigants.
20. Choice a) is correct. Cyanide is called a “gasp” poison because of its rapid onset of action and
prominent inhibition of mitochondrial function at the terminal phase of electron transport. Sulfuryl
fluoride and methyl bromide have multiple potential mechanisms of toxicity, including inhibition of a
number of enzyme systems; however, the toxicity is not characterized as sudden death, as with cyanide.
While phosphine is also a cellular poison, its action at a different portion of the electron transport chain
results in a less complete cellular toxicity. Chloropicrin is a lacrimator added to odorless fumigants such
as sulfuryl fluoride as a warning agent; it has fumigant properties as well.
21. Choice a) is correct. Chloropicrin is an odorless lacrimator, with this irritating property considered
more consistent and reliable than an odorous agent, such as mercaptans (added to natural gas as a
warning sign). Hydrogen sulfide and organophosphates are toxic chemicals in their own right. A colored
non-volatile dye would not be a useful detection agent for gases.
22. Choice a) is correct. Chloropicrin causes intense tearing secondary to irritation of mucous membranes
at concentrations below 1ppm. It is used with sulfuryl fluoride, which is an odorless fumigant, as a
warning/detection agent in structural fumigation. Methyl bromide, phosphine, and cyanide are all
fumigants or (historically) pesticide agents.
23. Choice a) is correct. Cyanide antidotes include the three-part cyanide antidote kit comprised of amyl
nitrite perls for inhalation, sodium nitrite, and sodium thiosulfate; the presumed mechanism of action is
conversion of a small amount of hemoglobin to methemoglobin by the nitrites. This serves as a sink for
cyanide to bind (in preference to the Fe3+ of the mitochondrial cytochrome oxidate a-a3); the
cyanomethemoglobin is subsequently returned to deoxyhemoglobin and the cyanide converted to
thiocyanate by the action of sodium thiosulfate on rhodanese. A second antidote is the precursor of
vitamin B12, hydroxocobalamin. The other agents do not have specific antidotes, and exposure is
managed with supportive care.
24. Choice a) is correct. Vitamin B12 is cyanocobalamin. The precursor hydroxocobalamin can be used in
doses of 5-10 grams IV (for an adult) to treat cyanide poisoning. Symptomatic exposure to the other
agents is managed with supportive care.
25. Choice a) is correct. The September 2003 joint DHS and FBI bulletin identified ‘home brew” cyanide
gas with introduction into building ventilation as a credible terrorist threat. This led to a series of
recommendations regarding evaluation of and “hardening” of vulnerable sites at businesses, hospitals,
and offices. The scenarios described in b) and d) may lead to increased availability of chloropicrin and
aluminum phosphide, respectively. The other scenarios would be events that would be evaluated by the
FBI for their threat significance.
26. Choice a) is correct. The purchase of a cyanide salt over the internet by a teenager and its use to poison
and kill a presumed rival for a girlfriend is an example of the need for improved tracking of hazardous
substances/reagents. Sulfuryl fluoride, methyl bromide, phosphine (as aluminum or zinc phosphide),
and chloropicrin are regulated pesticides, and should not be available directly to the lay public (unless
diverted, stolen; or in the case of phosphine, produced as a byproduct of illicit methamphetamine
manufacture).
27. Choice b) is correct. EPA has the regulatory authority for public drinking water systems (serving
>90% of the public – each system serving at least 25 people [or 15 “service connections”] for at least 60
days of the year). Enforcement is generally through state-run programs, though some jurisdictions are
under direct EPA authority. Although a number of primary and secondary water contaminants are
determined by the EPA, the EPA does not designate the methods used to achieve safe water quality.
FDA and USDA share regulatory authority for food items.
28. Choice d) is correct. Chlorine disinfection and chemical hazard mitigation is concentration- and timedependant. Some entities, such as protein poisons, are more easily denatured, than are simple salts.
Spores are resistant to disinfection by chemical agents such as chlorine. Chlorine is added to water
systems after coagulation, flocculation, filtration, and other physical steps. The removal of gross
contaminants increases the utility of the chlorine and its ongoing residual action against bacteria and
viruses; and decreases the formation of potentially harmful compounds, such as chlorine disinfection
byproducts. Ozone is an effective sterilizer, but has no residual effect, increasing the risk for postdisinfectant contamination.
29. Choice a) is correct. It is estimated that more than 80% of the food supply in the U.S. is regulated by
FDA; the remainder being under the regulatory authority of the US Department of Agriculture (USDA)
and the Department of the Interior, or other agencies. The sometimes overlapping or confusing areas of
jurisdiction are seen in the case of milk production, where USDA regulates the cow, but once the milk is
obtained, that product falls under FDA regulation (for the most part). The food safety system in the U.S.
was designed to detect accidental contamination or food spoilage, and to ensure a given standard of food
quality/safety; it was not designed to anticipate or detect intentional acts of food terrorism. Several
improvements, including the development of a network of food laboratories (the Food Emergency
Response Network – FERN), address terrorism concerns, while further modifications of the regulatory
network are anticipated.
30. Choice a) is correct. Many intentional events of food contamination with chemicals would have the
similar initial symptoms (nausea, vomiting, and/or diarrhea) associated with other food-borne outbreaks.
The potential gaps in the food safety system have been demonstrated in multiple events and models with
points of entry at various points in the food chain. The difficulty in detecting terrorist events initiated
early in the food chain derive from the large-scale production and distribution systems common for
much of the U.S. food supply (so called “bow-tie” production/distribution system). Milk in the U.S. is
pasteurized at a temperature that is not protective against introduction of a number of biotoxins or other
agents.
31. Choice b) is correct. The “Tylenol Act” was passed by Congress in 1983. Of the multiple facets of the
law, malicious tampering with consumer products was made a federal offense. Subsequent introduction
of tamper-evident packaging was an important effort to prevent intentional drug contamination. Quality
control for produced medication is a primary responsibility of the manufacturer. The FDA and
manufacturer will inspect medications and manufacturing sites when there is a report (from the public,
physician, or manufacturer) of adverse effects or other problems, but there is no routine inspection.
Terror attacks via the medication supply could focus on API (active pharmaceutical ingredient) or other
fillers/binders, as these latter ingredients may make up the majority of a tablet. MedWatch is a voluntary
reporting system whereby medical providers can notify the FDA of possible or known adverse
medication or device events.
32. Choice a) is correct. Delayed symptom onset results in dispersal of the event in both time and distance,
resulting in confusion (somewhat similar to that seen with infectious diseases). Syndromes caused by
delayed symptom onset toxins are recognizable, though less common than the rapid symptom onset
toxin. Many of these compounds are industrial byproducts, not necessarily easier or more difficult to
produce or obtain.
33. Choice c) is correct. Chloracne is a characteristic severe cystic acne caused by dioxins and
dibenzofurans. Acute symptoms following exposure are non-specific and generally mild or non-existent.
While highly carcinogenic in some animals, even high-dose exposure in humans is associated with
minor increased risk of non-Hodgkin’s lymphoma and possibly some other tumors. Neurological
toxicity is not characteristic, though described as a transient effect following the high-dose exposure in
the Seveso, Italy chemical plant explosion.
34. Choice b) is correct. Not only do different metals produce different toxic syndromes; the form of the
element is also critically important. As an example, simple organic mercurial compounds such as
methylmercury are more toxic than ethylmercury. Both of these have completely different presentations
than occurs following exposure to inorganic mercury salts. Some metals and metallic compounds (e.g.
methylmercury) are absorbed through skin, intact or not. Metals are not expensive and are available in
highly purified forms as reagents.
35. Choice a) is correct. Biopersistent compounds have generated concern because of the potential for
long-lasting health effects as they accumulate up the food chain or persist in an organism for monthsyears. Whether these concerns are valid or not, they help to generate the fear that is an integral part of
terrorism. Though dioxins have been released in large amounts by explosions, they are not explosive.
The clinical syndrome associated with significant dioxin and some other organochlorine exposures
(chloracne) is a classic toxic syndrome. Although the delayed symptom onset toxins can be similar to
infectious diseases such as smallpox in terms of timing of onset, chemical exposure to organochlorines
are not transmissible between people.
36. Choice c) is correct. Most health care workers and all other people are exposed to radiation sources
daily. The annual average 3 mSv (300 mrem) dose of ionizing radiation comes from the sun,
radionuclide-containing granite and other bedrock sources in our food, water, and air. Variability occurs
with altitude and geography. Routine shielding and distance as practiced when performing diagnostic
tests involving radiation prevent any significant exposures. Caring for patients contaminated by
radiation also contributes very little to total radiation dose. Estimates of the amount of radiation received
by the initial Chernobyl “liquidators” (involved in the initial plant cleanup) is on the order of 100 mSv
(or 10,000 mrem). Consumer products contribute small, but negligible amounts to total radiation dose
(mrem range). These considerations are important in understanding that radiation is a continually
present “toxin.” Although regulatory models use a “no threshold” assumption for carcinogenesis (“even
one photon could cause cancer”), this is a precautionary modeling and does not relate to reality.
37. Choice d) is correct. Patients who have been irradiated (e.g. after an X-ray) are not themselves
radioactive. Even those patients contaminated with radionuclides (e.g. after I131 thyroid treatment,
blast injury from a radionuclide-containing explosive) pose little risk to caregivers or other bystanders.
Because of this, priorities of life-saving stabilization should precede decontamination, and
decontamination should occur as a deliberate process while providing ongoing patient care.
38. Choice c) is correct. Burn injury due to heat is evident by degrees ranging from erythema to blistering
to deep tissue loss. Charring is diagnostic of severely burned tissue. Immediate skin changes secondary
to whole-body gamma radiation do not occur. Erythema and other skin changes in the setting of
significant beta radiation exposure can occur (Cutaneous Radiation Syndrome) in the absence of
systemic Acute Radiation Syndrome (ARS), but not immediately following exposure.
39. Choice d) is correct. This exposure of >10Gy is lethal and is characterized as the cerebrovascular
syndrome. The prodromal phase occurs with any type of radiation exposure, but is shorter the greater the
radiation exposure. The hematopoietic and gastrointestinal syndrome are seen at lower total body doses,
and are characterized by severe bone marrow suppression (>1Gy), and significant diarrhea and
hematochezia (usually with >4Gy), respectively. Note that vomiting is an early sign seen with all of
these syndromes.
40. Choice d) is correct. Serial measurement of the fall in the absolute lymphocyte count over the first 24
hours is the best objective indicator of severity of radiation exposure and prognosis. In combination
with the onset of vomiting, these immediately available indicators can assist with planning for resource
needs and allocation. RBC and platelet counts will fall in those with significant exposure, but this may
not be evident for weeks. Reversible increases in lung permeability can occur within hours of wholebody radiation exposure, but significant pulmonary edema with decrements in oxygen saturation is not a
sensitive measure of serious radiation exposure.
41. Choice b) is correct. External contamination is indicated by the presence of radioactive particles on the
skin, hair, or clothing. While radiation may be emitted from these sources, the person is not themselves
radioactive. This is different than an exposure to ionizing radiation, in that exposure is ongoing. Care
should be taken during decontamination to prevent internalization of these particles, a situation that is
significantly more worrisome.
42. Choice c) is correct. Radioactive particles within a wound can be transported by the blood or lymph,
and/or become incorporated within the tissue. Careful skin decontamination and repeated use of a survey
meter are important steps in radiation-contaminated wound management. Stroke is not a specific
concern related to radiation-contaminated wounds. Tissue necrosis and local radiation injury are delayed
consequences of ongoing radiation exposure and can also be minimized by good decontamination.
43. Choice a) is correct. This group of concerned individuals may have difficulty interpreting stress
reactions (e.g. catecholamine release) or may be responding to anxiety, media hyperbole, or ignorance.
In past large-scale events, this group has been many times the size of those with symptoms actually
referable to a chemical exposure. Individuals with external contamination are more likely to exhibit
symptoms referable to the chemical, whether it is volatile or a solid or liquid released in proximity to
those individuals.
44. Choice b) is correct. This term, while common, sets up a confrontational situation and may be
counterproductive to redirecting those with non-specific symptoms or concerns in the setting of a largescale chemical exposure. While common, particularly in settings with triggers such as odors, the ratio of
anxious to ill varies from 2:1 to >10:1. Autonomic arousal and anxiety are different than panic, and can
often be used to direct people towards actions that will minimize panic. Panic, which is a sudden fear
without rationale thought, is not common during large-scale chemical exposures, but is more likely in
settings of confined space, lack of leadership or planning.
45. Choice a) is correct. Discussions emphasizing the cycle of autonomic arousal and fear/anxiety can help
people focus on relaxation or other techniques in the setting of appropriate reassurance to resolve their
symptoms. It should be recognized that many of the arousal symptoms (e.g. sweating, nausea, dizziness,
palpitations, paresthesias, headache, difficulty in breathing) may mimic chemical toxidromes, and may
be difficult to distinguish early in an event. While distinct from panic, these symptoms can escalate in
the absence of communication, reassurance, and reassessment. Some features that may assist in
identifying functional somatic symptoms include a lack of apparent dose response and so-called “line of
sight” transmission, whereby another person witnessing symptoms in another “catches” the condition.