Terrorist Chemical Releases: Assessment of Medical Risk and Implications for Emergency Preparedness
- Terrorist Chemical Releases: Assessment of Medical Risk and Implications for
In the last few years, public health has played an increasingly important
role in disaster management, particularly in biological terrorist event
planning. However, little time or financial expenditure has been spent on
preparation for terrorist-related chemical events. In addition, chemical
hazardous material and industrial accidents are common occurrences in the
United States and have significant public health and emergency preparedness
consequences. This manuscript reviews previous terrorist-related and
industrial chemical events, an assessment of the risk that these events have
on the public health, and ways that hospitals and local, state, and regional
public health agencies may plan for such an event.
Key Words: emergency preparedness, chemical agents, terrorism, risk
assessment, emergency medicine.
Over the last several years, and following the incidents of September 11,
2001, much energy has been expended preparing for a terrorist event. The
majority of the concern and monetary expenditures have been in preparing for
the release of biological agents. However, there are multiple recent
real-world examples of terrorist and military releases of "chemical agents."
Although there are similarities in planning, chemical events differ from
biological and radiological events in several ways. Chemical events produce
victims who develop symptoms simultaneously, leading to an initial mass
casualty event. This is typically followed by large numbers of patients
reporting over a broader time frame that is more typical of biological
events. Chemicals have the potential to immediately affect and incapacitate
health care workers, leading to the combination of a mass casualty event
with a limited health care workforce. And, of course, chemicals may require
the delivery of antidotal therapy within minutes of exposure, making
reliance on regional caches impossible. This article will attempt to review
both intentional and accidental chemical releases, discuss the risks
involved, and discuss preparations that are necessary.
"Chemical agents" are those chemicals that may be released by terrorists or
militaries with the aim of producing mass casualties. They include agents
that have been developed by military organizations (e.g., nerve agents,
vesicants), as well as chemicals that are routinely used in industrial
processes (e.g., cyanide, phosgene, hydrofluoric acid, chlorine, ammonia).
Many of these chemical agents are among the most potent chemicals known.
Terrorist releases may occur in several different ways. The purposeful
release of an industrial chemical from a fixed facility or transportation
vehicle is the least complex and probably the most likely event. Many of
these industrial chemicals are ubiquitous in American cities and typically
act as irritant gases (e.g., ammonia, chlorine, phosgene), although
industrial chemicals may also have systemic effects (e.g., cyanide, hydrogen
sulfide). Alternatively, terrorists may choose to manufacture more
sophisticated chemical agents, such as nerve agents (e.g., VX, sarin, soman,
tabun) or mustard. Although the technical aspects of manufacturing these
agents has been fine-tuned by the world's militaries over the last century,
their manufacture would require the clandestine production of a large volume
of chemical, which may be difficult. Table 1 reviews the clinical features
of the most likely chemical agents and their characteristics.
Although some of these agents have lethal doses in the milligram range
(Sidell and Borak 1992; Sidell and Groff 1974), when these agents have been
deployed in real-world scenarios, large numbers of casualties, but few
actual fatalities, have been produced (Trumpener 1975; Hyams et al. 2002;
Okumura et al. 1996; Morita and Yanagisawa 1995; Wing et al. 1991).
Historically, both terrorist-related and accidental chemical-releases have
resulted in widespread fear, anxiety, and overwhelming numbers of mildly
affected casualties. This large number of asymptomatic to mildly symptomatic
patients represents the largest risk to the health care system from chemical
agents and should be a main focus of emergency preparedness and public
WHAT ARE THE CHARACTERISTICS OF PREVIOUS CHEMICAL RELEASES?
Large-scale chemical releases have historically produced hundreds to
thousands of mildly symptomatic patients, but few fatalities (Okumura et al.
1996; Wing et al. 1991; Okumura et al. 1998; Okudera et al. 1997). Several
examples have been described in the medical literature and will be discussed
In June 1994 a religious-based organization, named the Aum Shinryko,
released vaporized sarin nerve agent within the city of Matsumoto, Japan.
The group used a converted refrigeration truck that was equipped with metal
tanks, a heater, and a fan to produce a sarin vapor that was released from
the truck while it was parked outside a residential apartment building.
Despite releasing the vapor in a populated residential area, only 600 of the
city's 200,000 residents were affected. Fifty-eight of the residents were
hospitalized and seven people died (Morita and Yanagisawa 1995).
Table 1. Characteristics of common chemical agents.
The following year, in March 1995, the same organization again released
sarin, this time into five Tokyo subway cars during Monday morning rush hour
(7:55 a.m.). The targeted subway station was situated directly beneath the
Japanese National Government's ministry offices (Okumura et al. 1996).
Following the event, more than 5000 people sought medical care (Okumura et
al 1996). St. Luke's International Hospital, situated within 3 km of the
event, cared for more than 500 patients within the first 2 hours after the
release and 640 in the first day (Okumura et al. 1996). Sarin is an organic
phosphorous compound ("nerve agent") that requires low concentrations to
produce fatalities (liquid LD50 = 1.7 g),1 particularly in its vapor form
(LCT50 = 100 mg min/m^sup 3^).2 Sarin evaporates readily and was an ideal
agent to use for this type of attack. However, despite the release of this
agent in an enclosed, crowded space, only 12 citizens died (Okumura et al.
In October, 1987, 53,000lbs of hydrofluoric acid were accidentally released
from a petrochemical plant in Texas (Wing et al. 1991). The release produced
a vapor cloud that covered a community of 41,000 residents, sending 939
citizens to area hospitals. Of the exposed, 94 were admitted to hospital,
and there were no deaths reported (Wing et al. 1991).
One example of a large-scale military chemical release has been well
described. In April 1915, the German military released more than 150 tons of
chlorine near Ypres, France. The chlorine was stored in thousands of
canisters placed within the German trenches and opened when the wind blew
toward the Canadian and French troops. Although politically motivated
reports have described thousands of deaths, actual French and German
accounts from the time refer to 625 casualties and 3 deaths (Trumpener
In 1984, the world's worst industrial disaster occurred in Bhopal, India.
Late at night on December 2, over a 1-2 hour period, approximately 27 metric
tons of methyl isocyanate (MIC), and possibly phosgene, hydrogen cyanide,
nitrogen oxides, and carbon monoxide, were released in proximity to a highly
populated area (Ramana Dhara and Dhara 2002). Environmental factors,
including low wind speed and a thermal inversion, prevented dissipation of
the chemicals and resulted in exposure of 200,000 of the 900,000 residents
of Bhopal (Ramana Dhara and Dhara 2002; Singh and Ghosh 1987). The release
produced more than 80,000 victims with approximately 3,000 deaths (Varma and
Guest 1993). There has been considerable controversy over whether the
release was an industrial accident or the intentional act of
individuals/terrorists. In either case, Bhopal is a striking example of the
effectiveness of chemical agents. However, it should be noted that the mass
fatalities in Bhopal were due to the tremendous volume of chemicals used,
the location of the release (populated area), and favorable environmental
WHY ARE CHEMICAL RELEASES MORE LIKELY TO PRODUCE MASS CASUALTIES AND NOT
In several of the earlier examples, despite the use of large volumes of
chemicals (Texas and Ypres) or their use in enclosed spaces (Tokyo),
releases of chemicals have produced few fatalities. The one instance of
significant fatalities (Bhopal) required very large volumes of chemicals,
released in a populated area with favorable environmental conditions.
The difficulty in producing fatalities with chemical agents may be due to
several factors. First, it is difficult to produce an airborne cloud of
chemicals in open air that have adequate local concentration to kill a
substantial number of people. Occasionally, lethal concentrations have been
produced in small or enclosed areas, such as within a theater in Moscow in
2003 (Wax et al. 2003), or with very large volume releases, as in Bhopal
(Rhamana Dhara and Dhara 2002). However, the development of a lethal
threshold airborne concentration in a large area, such as a stadium or
open-air venue, may be difficult to produce and would likely require
tremendous volumes \of chemical with an advanced dispersal device and
favorable environmental conditions. The reasons for this can be shown using
a simplified model. Say, for example, a terrorist targeted an open- air
baseball stadium. The example stadium (based on an actual stadium) is
1,172,127 square feet with a 215 foot retractable dome. If a terrorist chose
sarin as the chemical agent, how much chemical would be necessary to produce
mass fatalities? Sarin has an LCT50 of 100 mg min/m3. If wind direction,
wind speed, and the problems of dispersing the agent (which are numerous)
are ignored, and assuming a homogenous vapor breathed for one minute, then
to kill 50% of the attendees would require 860 kg of sarin,3 which is about
781 liters (206 gallons) of pure sarin liquid.
The earlier example scenario ignored several significant factors that
decrease a released chemical agent's effectiveness: wind direction and
speed, precipitation, chemical purity, and the method of dispersal (see
Table 2). Accounting for these factors would likely require a manyfold
increase in the necessary volume of chemical.
The method of dispersal of chemical agents also affects the concentration of
chemical at the target, and therefore, the consequential fatality rate.
During the 1950s and 1960s, many of the world's militaries attempted to
solve the problems of volume and environment by producing weapons that would
bring the chemicals close to the enemy and then release. Although simple
mortars were initially used, more "successful" projectiles were later
produced that required technologically advanced mechanisms for release. For
example, the "Honest John" rocket (1960) was a medium range rocket that
contained about 50 small spherical bomblets. The bomblets contained an
explosive central burster with sarin-filled outer compartments. The
bomblets' shape initiated a spin that armed the impact fuse (Sidell et al.
1997). Advanced technology weapons such as these are not likely to be
obtained or used by terror organizations, although state-sponsored
organizations may have such access.
Table 2. Representative factors that may influence the casualty rate of
Another method of dispersal that has been theorized is the direct
introduction of a chemical into the air-intake of a large stadium. This type
of dispersal may be more difficult to perform than an open- air release,
because it requires control of the building and the air- intake system.
However, this type of dispersal may require a small, yet still significant
volume of chemical. For example, using the simplified model above, producing
50% fatalities in a large hockey or basketball arena would require at least
164 kg (149 Liters) of sarin.4 Again, transportation of this volume of
liquid would be difficult without attracting attention, however, a smaller
volume could certainly produce casualties without producing large numbers of
The volume of chemicals necessary and the complexity of dispersal devices
required to produce massive fatalities may be significantly prohibitive for
a terrorist organization and be difficult to conceal from authorities.
However, releases of smaller amounts of chemical, or from less sophisticated
dispersal systems, may produce large numbers of victims exposed to smaller
concentrations, or simply produce terror without exposure. Using the earlier
sarin analogy (with all of its limitations), it would require only 6.2
gallons of sarin to produce miosis, and therefore blurry vision, in half of
the crowd at the example baseball stadium [CT50 (miosis) = 3 mg min/ m^sup
3^]5 and only 1.8 gallons to produce the same effect in a hockey arena. A
similar effect may be produced by releasing large volumes of chemical agents
into the open air from industrial sites or transportation vehicles (e.g.,
rail cars) that are not directly within high-density population areas.
WHY DO ASYMPTOMATIC OR MILDLY SYMPTOMATIC PATIENTS PRESENT TO HEALTH CARE
Historically, after chemical releases, large numbers of people seek medical
care at health care facilities (HCFs), such as emergency departments and
primary care offices. In the 1994 sarin release in Matsumoto, Japan and the
1995 sarin release in Tokyo, Japan, 80-90% of all patients reporting to the
emergency departments had mild or no complaints (Okumura et al. 1996; Morita
and Yanagisawa 1995). Similarly, in the 1987 release of anhydrous
hydrofluoric acid in Texas, 90% of the 932 patients seen in emergency
departments were discharged to home and 15% had no complaints at all (Wing
et al. 1991).
Patients with mild complaints or concerns may continue to present to HCFs
for several days, even after releases of immediately acting chemicals (Wing
et al. 1991; Okumura et al. 1998). For example, after the 1996 Tokyo sarin
attack, one hospital received 640 patients on the day of the release. Over
the next 6 days, they received an additional 770 patients related to the
attack (Okumura et al. 1998). Following the hydrofluoric acid (HF) release
in Texas, HF-related complaints continued to be greater than one-fourth of
the emergency department volume for more than four days (Wingeiai 1991).
So, why do victims of chemical events present to HCFs when they have few or
no symptoms? And why do they present several days after exposure to
chemicals that are rapidly acting? To answer these, we must review the
various physical and psychological factors that motivate victims to seek
Patients exposed to low concentrations of chemicals may develop mild, yet
irritating or disconcerting symptoms. Many of the chemical agents used by
militaries were designed for this purpose. Chlorine, for example, was used
extensively in WWI, with its main effect the production of mucosal
irritation and incapacitation of enemy troops. Victims of the sarin release
in Tokyo also largely developed eye and mucosal symptoms, in that case
lacrimation and miosis (Okumura et al. 1996). Although symptoms such as
blurry vision may be non- systemic, non-life threatening, and described as
"mild" in the health care setting, they are very concerning, worrisome, and
irritating to patients. It is important to note that the vast majority of
patients report to HCFs for entirely rational reasons; because they either
have symptoms or they don't know what symptoms require treatment.
Many patients with mild complaints may report to HCFs hours or days after
the release. There are numerous possible explanations for this behavior.
Some patients may believe that their mild symptoms will resolve quickly and
only present later, when symptoms persist. Others may determine that mild
symptoms are tolerable until they can determine and secure the safety of
their families. Finally, several chemicals may produce subtle symptoms after
low concentration exposure (e.g., nerve agents) (Brown and Brix 1998). These
subtle symptoms may not be initially recognized and may be difficult to
differentiate from health effects from other diseases, exposures and anxiety
reactions (Brown and Brix 1998; Nakajima et al. 1998).
While patients may seek care chronologically distant to the event, for
similar reasons they may also present at geographically distant sites,
including primary care and obstetrical offices, acute care clinics and
distant emergency departments.
Confusion, Anxiety, and Chemical-Phobia
The concept of the domestic use of weapons of mass destruction, either
conventional or unconventional, is frightening and anxiety provoking for the
general public. Several characteristics of chemical terrorist acts may
produce a unique and enhanced sense of vulnerability in the public (Hyams et
al. 2002): (1) Terrorist events are involuntary and unpredictable, (2) They
may occur in locations that were previously deemed "safe" (e.g., workplace,
home), (3) Chemical threats are unfamiliar scenarios, and (4) Chemical
events pose a danger to patients' families. Chemical weapons have the
additional stigma of being exotic weaponry developed, stored, and deployed
by the military with little public knowledge. All of these factors
contribute to the significant public anxiety concerning chemical events
(Hyams et al. 2002).
The general public does not have a complex understanding of chemical
principles and the risks of exposures to chemical agents. Agents are
typically concretely divided into "toxic" and "non- toxic" chemicals, of
which industrial and military agents are "toxic." Much of the public's
knowledge of chemical agents may have been derived from WWI and political
propaganda, sensationalistic media reports, and entertainment. One needs
only to look at the adjectives used by the media to describe chemicals to
understand why the general public is frightened: toxic, killer, lethal,
deadly, caustic, and so on. The public has associated these adjectives, as
well as images of massive death and suffering, with the release of any
chemical. Given this ingrained fear of these "deadly" chemicals, it is
difficult to communicate that a low concentration exposure to a "deadly"
agent may not produce symptoms or long-term effects. The concept of a
dose-response curve for "lethal" agents is not an easy concept when, by
definition, the agent is "lethal."
People who feel they may have been exposed to a chemical may seek medical
assistance after noticing previously existing symptoms and connecting them
to the event. Nonspecific complaints are common in the general population.
Approximately 20-30% of people who consider themselves healthy and well,
report fatigue or musculoskeletal symptoms when directly asked (Barsky and
Borus 1999). In fact, 81% of healthy college-aged students report somatic
symptoms over any 3- day period (Barsky and Borus 1999; Reidenberg and
Lowenthal 1968). These non-specific symptoms include headache, nausea,
dyspnea, paresthesias, problems with memory, palpitations, dry mouth, and
lightheadedness, which may be easily attributed to a chemical agent
(Barskyand Bonis 1999).
Widespread anxiety and fear of terrorist acts exists in the general
population, particularly from unusual, foreign, and "lethal" chemical
agents. During a large chemical release, it is likely that a large group of
people with a perceived exposure may report to health care workers with
symptoms related to anxiety or unconnected nonspecific symptoms. Concerned
citizens may view HCFs as safe locations, as well as logical locations for
sources of information concerning exotic and unusual chemicals.
Mass Psychogenic Illness
During a chemical disaster, the public's concern of the health effects of
exposure may contribute to individual and group symptomatology. This shared
anxiety may produce "victims" who require evaluation by HCFs despite not
being exposed to a significant amount of chemical. This phenomenon is called
mass psychogenic illness (MPI), and is also known as mass sociogenic illness
or epidemic hysteria. MPI is defined as a constellation of symptoms that are
suggestive of an organic illness, but without an identified cause. The
symptoms occur in groups with shared beliefs about the cause of the symptoms
(Jones et al. 2000). MPI typically occurs in large groups who are in
stressful situations and is commonly brought on by environmental triggers,
such as odors (Jones el al. 2000). Suspected chemical releases are a common
trigger and several MPI events have occurred after the suspected detection
of a "chemical smell" (Wessely e,t al. 2001; Bartholomew and Wessely 2002).
Symptoms in MPI victims are typically nonspecific, such as lightheadedness,
headache, nausea, chest tightness, dyspnea, and drowsiness (Jones et al.
2000; Bartholomew 2002; Spitters et al. 1994). MPI symptoms may be easily
mistaken for those produced by low concentration chemical exposures.
Unfortunately, the misdiagnosis of MPI symptoms as the effects of chemicals
may reinforce the patient's symptoms (Barsky and Borus 1999). Reinforcement
of MPI symptoms by authorities and health care providers may increase
concern in the community and potentially produce additional MPI victims
(Barsky and Borus 1999).
The risk and intensity of MPI is higher if the suspected causative factor is
foreign to victims (Barsky and Borus 1999), as is the case with most
chemical agents and industrial chemicals. Symptoms typically "spread"
rapidly and in a pattern that is consistent with "line of sight" spread or
via communication lines (e.g., over the telephone), rather than the typical
geographical or close personal contact spread of disease or contamination
(Spitters et al. 1994). Additionally, there may be asymptomatic people
interspersed and juxtaposed with symptomatic people who shared the same
"exposure" (Jones et al. 2000).
Several MPI episodes have occurred as a result of concerns of chemical
terrorism. During the 1991 Persian Gulf War, it was postulated that Iraq
would use chemical weapons against Israel. After several missiles that did
not contain chemicals were fired, almost one-half of the residents of an
Israeli community reported breathing problems (Carmeli et al 1991). In 1983,
949 people in the West Bank of Jordan reported a variety of nonspecific
symptoms over a two-week period. Initial victims detected a sulfur smell in
a school (likely a broken toilet). Additional victims occurred due to
large-scale media coverage and an underlying fear that Israel had deployed a
"poison gas" (Modan et al. 1983). A similar episode occurred in Georgia
(Russia) in 1989 when false rumors that the Russian government had used
chloropicrin on a crowd led to more than 400 patients complaining of mucosal
irritation (Bartholomew and Wessely 2002).
Considering the current anxiety about terrorist events, MPIs can be expected
with high frequency in the event of a chemical disaster. Unavoidable
vigorous responses from authority, including PPE-clad hazardous materials
teams, governmental agencies, and health care personnel, may exacerbate and
reinforce MPI symptoms and expand the victim pool (Kovalchick et al. 2002).
Low Concentration Exposure to Chemicals
Symptoms of MPI or anxiety may be quite difficult to differentiate from an
exposure to a chemical agent. Several chemicals, including organic
phosphorous compounds (e.g., nerve agents, organophosphate pesticides),
carbon monoxide, hydrogen sulfide, and ricin may produce nonspecific
symptoms without outward physical findings (Brown and Brix 1998). Exposure
and toxicity may be determined by identification of the agent at the sight
of exposure, by laboratory examination of the patient (e.g., cholinesterase
activity/organic phosphorous compounds, carboxyhemoglobin
concentration/carbon monoxide, metabolic acidosis/ hydrogen sulfide), and
may be predicted using environmental data, plume simulation, and on-site
WHAT TO EXPECT
Large chemical releases have historically produced hundreds of victims who
arrive to hospital emergency departments within the first several hours
(Okumura et al. 1998). There is typically a brief "ramp up" period between
the time of the release and the arrival of the first patients (<1 hour)
(Okumura et al. 1998; Okudera et al. 1997). Most patients arrive by foot or
private conveyance, and fewer than 20% arrive via police, fire, or EMS
vehicle (Okumura et al. 1998). Although the vast majority of patients
arriving in the early stages are mildly symptomatic, the most severely
affected patients are also likely to arrive at this time (Kovalchick et al.
After this initial influx of patients, a large increase in volume to
hospital emergency departments and primary care offices should be expected
over the next week or more (Wing et al. 1991; Okumura et al. 1998). The
majority of these victims have complaints that are mild, stress-related, or
simply have concerns and request information. Primary care health care
workers may see an increase in visits from patients who are concerned about
exposure to chemicals that may have entered the food and water supply.
Patients may request information about chemical exposures and their risk of
long- term medical problems, including cancer. Additional questions should
be expected from pregnant patients with concerns about teratogenicity and
fetal effects of chemical exposures.
WHAT CAN BE DONE TO PREPARE?
HCFs, including hospitals and primary care offices, should be prepared for
an initial influx of patients shortly after an event as well as a sustained
increase in volume over several days to weeks. Regional public health plans
should consider health care sites that are distant to hospitals and offices
to decompress these health care facilities. These regional health care sites
should consider the use of a mobile decontamination system, and include a
system to triage patients to a higher level of care (e.g., ambulances to
transport patients to area hospitals), if necessary. Disaster plans must
keep in mind that most patients who seek health care are mildly symptomatic
or asymptomatic and that differentiating between symptoms of mild exposure
and psychosomatic or unrelated symptoms may be difficult. In certain cases,
laboratory evaluation may be available to confirm exposures (e.g., nerve
agents) and patients may require additional testing or repeat visits after
discharge from HCFs. Additionally, a regional health care plan may include
the use of the regional poison center to follow patients at home by
telephone and to give educated advice on treatments and the need to be seen
in health care facilities. Most importantly, patients initially, and over
the short term, require accurate information about the exposure and their
expectations for recovery or chronic symptoms (Kales and Christiani 2004;
Brennan et al. 1999). Regional disaster plans should include a method of
obtaining rapid, accurate chemical and decontamination information, possibly
from the regional poison control center, local resources, or federal
agencies (e.g., ATSDR, CDC) to distribute to health care workers (first
responders, emergency departments, primary care offices, etc.) (Brennan et
al. 1999; Greenberg and Hendrickson 2003). The possibility of pre- written
data sheets that are rapidly available to health care workers either via fax
or electronic media may be considered as most health care workers are not
knowledgeable on rare chemical exposures.
Training and education should be considered to address the psycho- social
aspects of disaster management. Few HCWs have training on the diagnosis and
management of acute and sub-acute psychological reactions. Planning should
address the issues of acute exacerbations of chronic psychiatric diseases
due to acute stress or limited access to psychiatric medications and
counseling, as well as acute disorders in patients without previous
psychiatric disorders. Planning may include the identification of caches or
storage facilities of common medications that are prescribed for psychiatric
problems, including schizophrenia, depression, and anxiety disorders.
Planning may include a method of dispersal of these medications to the
public or through primary health care workers if pharmacies and hospitals
are overwhelmed. Regional groups of psychiatrists, social workers, and
psychologists should be included in disaster planning.
Risk communication is a key aspect of any disaster plan and because of the
difficult concepts involved and the public's concerns about chemicals in
general, is particularly important during chemical exposures. Disaster plans
should include rapid access to accurate information about acute and chronic
effects of chemicals that are rapidly and clearly communicated at a level
that typical citizens may understand. Disaster procedures should allow for
communication between regional spokespeople, including the regional poison
center, the regional public health agency, hospitals, and the media, so that
a coordinated, single message concerning risks and procedures may be
communicated to the publi\c (Richards et al. 1999). Rapid and planned
communication with the media should be considered to express this
coordinated message and to communicate instructions to victims.
Resources for emergency preparedness typically concentrate on the few
severely ill patients and the first responders and health care workers who
care for them. Additional resources must be used for preparation for the
many patients who arrive to HCFs with mild symptoms and are served with
minimal medical care, but with accurate and rapid information that is
coordinated through HCFs (hospitals, offices), regional poison centers,
regional public health agencies, the media, and the regional/national
spokespeople (e.g., CDC).
1 LD50 = lethal dose 50%: This is the dose of liquid that would kill 50% of
people to whom it was applied.
2 LCT50 = lethal concentration-time 50%: This is the concentration of
airborne chemical that would kill 50% of people who breathed it for one
3 Volume of stadium = 1,172,127 ft^sup 2^ 215ft (height of roof) = 130236
m^sup 2^ 66 m = 8,595,576 m^sup 3^.
Kg sarin required = LCT50 Vol = 100 mg min/m^sup 3^ 8,595,576 m^sup 3^ = 860
Liters sarin required = 860 kg l mL/1.1 g (at 20C) (Sidell et al. 1997, p.
141) = 781L.
4 Arena volume = 383,528 ft^sup 2^ 150 ft height = 57,529,200 ft^sup 3^ =
35,649 m^sup 2^ 46 m = 1,639,854 m^sup 3^.
Kg sarin required = LCT50 Vol = 100 mg min/m^sup 3^ 1,639,854 m^sup 3^ = 164
Liters sarin required = 164 kg 1 mL/1.1 g (at 20C) (Sidell et al. 1997, p.
141) = 149 L.
5 Ct50(miosis): This is the concentration at which 50% of exposed patients
would develop miosis after exposure for one minute (Sidell et al. 1997).
Volume required in baseball stadium = Ct50 volume of stadium 1 mL/1.1 g
sarin = 3 mg min/m^sup 3^ 8,595,576 m^sup 3^ 0.91 mL/g = 23.4 L = 6.2
Volume required in hockey arena = Ct50 volume of arena 1 mL/ 1.1 g sarin = 3
mg min/m^sup 3^ 1,639,854 m^sup 3^ 0.91 mL/g = 4.48 L = 1.2 gallons.
Barsky AJ and BorusJF. 1999. Functional somatic syndromes. Ann Intern Med
Bartholomew RE and Wessely S. 2002. Protean nature of mass sociogenic
illness: From possessed nuns to chemical and biological terrorism fears.
Brit J Psych 180:300-6
Brennan RJ, WaeckerleJF, Sharp TW, et al 1999. Chemical warfare agents:
Emergency medical and emergency public health issues. Ann Emerg Med
Brown MA and Brix KA. 1998. Review of health consequences from high-,
intermediate-, and low-level exposure to organophosphorus nerve agents. J
Appl Toxicol 18(6):393-408
Carmeli A, Liberman N, and Mevorach L. 1991. Anxiety-related somatic
reactions during missile attacks. IsrJ Med Sciences 27(11- 12):677-80
Greenberg MI and Hendrickson RG. 2003. Report of the CIMERC/ Drexel
University Emergency Department Terrorism Preparedness Consensus Panel. Acad
Emerg Med 10(7) :783-8
Hyams KC, Murphy FM, and Wessely S. 2002. Responding to chemical,
biological, or nuclear terrorism: The indirect and long-term health effects
may present the greatest challenge. J Health Politics Policy Law
Jones TF, Craig AS, Hoy D, et al. 2000. Mass psychogenic illness attributed
to toxic exposure at a high school. N Engl J Med 342:96- 100
Kales SN and Christiani DC. 2004. Acute chemical emergencies. N EnglJ Med
Kovalchick DF, Burgess JL, Kyes KB, et al. 2002. Psychological effects of
hazardous materials exposures. Psychosomatic Med 64:841- 6
Modan B, Swartz TA, Tirosh M, et al. 1983. The Arjenyattah epidemic. A mass
phenomenon: spread and triggering factors. Lancet 2 (8365-66): 1472-4
Morita H and Yanagisawa N. 1995. Sarin Poisoning in Matsumoto, Japan. Lancet
Nakajima T, Ohta S, Morita H, et al. 1998. Epidemiological study of sarin
poisoning in Matsumoto City, Japan. J Epidemiol 8(1):33-41
Okudera H, Morita H, Iwashita T, et al. 1997. Unexpected nerve gas exposure
in the city of Matsumoto: Report of rescue activity in the first sarin gas
terrorism. Am J Emerg Med 15:527-8
Okumura T, Takasu N, Ishimatsu S, et al. 1996. Report on 640 victims of the
Tokyo subway sarin attack. Ann Emerg Med 28:129-35
Okumura T, Suzuki K, Fukuda A, et al. 1998. The Tokyo subway sarin attack:
Disaster management, part 2: Hospital response. Acad Emerg Med 5:618-24
Ramana Dhara V and Dhara R. 2002. The Union Carbide disaster in Bhopal: A
review of health effects. Arch Environ Health 57(5):391- 404
Reidenberg MM and Lowenthal DT. 1968. Adverse nondrug reactions. N EnglJ Med
Richards CF, BursteinJL, WaeckerleJF, et al. 1999. Emergency physicians and
biological terrorism. Ann Emerg Med 34(2):183-90
Sidell FR and GroffWA. 1974. The reactivatibility of cholinesterase
inhibited by VX and Sarin in man. Toxicol Appl Pharmacol 27:241-25
Sidell FR and Borak J. 1992. Chemical warfare agents: II. Nerve agents. Ann
Emerg Med 21(7):865-71
Singh MP and Ghosh S. 1987. Bhopal gas tragedy model simulation of the
dispersion scenario. J Hazard Mater 17:1-22
Smart JK. 1997. History of chemical and biological warfare: An American
perspective. In: Sidell FR, Takafuji ET, and Fran/ DR (eds), Textbook of
Military Medicine: Medical Aspects of Chemical and Biological Warfare, pp
58-9. TMM Publications (Office of the Surgeon General), Washington, DC, USA
Spitters C, DarcyJ, Hardin T, el al. 1996. Outbreak of unexplained illness
in a middle school-Washington, April 1994. MMWR 45(1):6-9
Trumpener U. 1975. The road to Ypres: The beginnings of gas warfare in World
War 1. J Modern History 47(3):460-80
Varma DR and Guest I. 1993. The Bhopal accident and methyl isocyanate
toxicity. J Toxicol Envir Health 40:513-29
Wax PM, Becker CE, and Curry SC. 2003. Unexpected "gas" casualties in
Moscow: A medical toxicology perspective. Ann Emerg Med 41 (5):700-5
Wessely S, Hyams KC, and Bartholomew R. 2001. Psychological implications of
chemical and biological weapons. BMJ 323:878-9
Wing JS, Sanderson LM, Brender JD, et al. 1991. Acute health effects in a
community after a release of hydrofluoric acid. Arch Envir Health
Robert G. Hendrickson
Department of Emergency Medicine, Medical Toxicologist, Oregon Poison
Center, Oregon Health and Science University, Portland, Oregon, USA
Address correspondence to Robert G. Hendrickson, M.D., Assistant Professor,
Department of Emergency Medicine, Medical Toxicologist, Oregon Poison
Center, Oregon Health and Science University, Portland, OR 97239, USA.
Copyright CRC Press Jun 2005
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Published: 2005/07/31 03:00:57 CDT
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