Esequiel Barrera, SM (TOX)
Biol/Chem Safety Officer
University of Texas
Southwestern Medical
Center at Dallas

• Agent characteristics
• History of use
• Modes of action
• Clinical
Manifestations
• Medical treatment
• Personal Protective
Equipment
• Decontamination
Acute Toxicity
• Chlorine gas
• Cyanide gas
• Mustard gas
• Incapacitants
• Nerve gas
• Botulinum toxin
• Ricin
• T2 Mycotoxin

• Chlorine is a powerful oxidizing agent
• Household chemicals such as sodium hypochlorite/pool chlorine tablets and muriatic acid (HCl) when mixed produce chlorine gas
• Chlorine and anhydrous ammonia are the most common hazardous materials in interstate commerce

• Chlorine gas is a respiratory irritant which affects the mucous membranes
• Chlorine is a toxic, corrosive, greenish yellow gas
• Gas is two and a half times heavier than air. It becomes a liquid at -34° C
(-29° F)

• Contact may cause burns to skin and eyes however the major concern is inhalation toxicity
• It can be fatal after a few breaths at 1000 ppm.
• Chlorine odor threshold ~0.3 to 0.5 ppm
• Medical treatment: move individual(s) to fresh air, administer oxygen if necessary
• Post-exposed Individuals generally recover to normal state

• Cough (52-80%)
• Shortness of breath (20-51%)
• Chest pain (33%)
• Burning sensation in the throat and substernal area (14%)
• Nausea or vomiting (8%)
• Ocular and nasal irritation (4-
6%)

• Under the Department of
Defense definition, an incapacitant is an agent that produces temporary physiological or mental effects, or both, which will render individuals incapable of concerted effort in the performance of their assigned duties

• The chemical warfare agent 3quinuclidinyl benzilate (QNB, BZ) is an anticholinergic agent that affects both the peripheral and central nervous systems (CNS). It is one of the most potent anticholinergic psychomimetics known, with only small doses necessary to produce incapacitation. It is classified as a hallucinogenic chemical warfare agent.

• QNB usually is disseminated as an aerosol, and the primary route of absorption is through the respiratory system. Absorption also can occur through the skin or gastrointestinal tract. It is odorless. QNB's pharmacologic activity is similar to other anticholinergic drugs (eg, atropine) but with a much longer duration of action.

• WWI agents such as cyanide and mustard gases introduced the horror of chemical warfare
• http://www.superevi
l.tv/rommel/rommel.
htm

• Easy to obtain potassium cyanide or other salts and react with acid to release cyanide gas cloud
• First synthesized in 1782
• Colorless gas, bitter almond odor
• A characteristic sign of cyanide poisoning is the bright red color of the blood in the comatose patient (some exceptions have been observed) due to the blood remaining fully oxygenated
• Blood agent

• Median lethal dose of potassium cyanide in man is 200 mg (taken orally) and death occurring in 1 to 2 minutes
• Hydrogen cyanide can cause rapid death due to metabolic asphyxiation.
• LC(50) in humans is 270 ppm in 6 to 8 minutes.
• Medical treatment: nitratethiosulfate combination antidote

• Lipid Peroxidation
• Elevated cell calcium
• Acidosis
• Ribosylation of mitochondrial protein
• Elevated blood ammonia and amino acids

• Headaches, weakness, changes in taste and smell, irritation of the throat, vomiting, effort dyspnea, lacrimation, abdominal colic, precordial pain, and nervous instability.

• First synthesized in 1859
• There are two types of mustards: the sulfur mustard and the nitrogen mustard and both share common chemistry in the formation of cyclic onium cation and free chloride anion
• Both liquid and vapor forms are readily soluble in oils, fats and organic solvents, can be quickly absorbed through the skin

• 2-4 hours experience chest tightness, sneezing, lacrimation, rhinorrhea, epistaxis, hacking cough
• Vesicant (blistering) properties, 2-3 days later.
• Immediate exposure determination upon detection of garlic/onionlike odor
• No effective medical treatment due to nonspecific alkylating nature of agent
• http://www.opcw.org/re sp/html/mustard.html

• More individuals have died of mustard gas than any other chemical agent or toxin
• Most of these deaths happened during WWI
• Emergency care effective less than
3% of WWI casualities results in death.
• http://www.opcw.org/resp/htm l/mustard.html

• Efforts must be made to treat the symptoms. By far the most important measure is to rapidly and thoroughly decontaminate the patient and thereby prevent further exposure. This decontamination will also decrease the risk of exposure to staff.
• Clothes are removed, the skin is decontaminated with a suitable decontaminant and washed with soap and water. If hair is suspected to be contaminated then it must be shaved off. Eyes are rinsed with water or a physiological salt solution for at least five minutes.

• Organophosphorus Esters
• Carbamate Esters
• Organophosphorus ester insecticides were first synthesized in 1937 by a group of German chemists led by
Gerhard Schrader

• Soman, Sarin and
VX these chemicals strongly bind to acetylcholinesteras e and effectively cause the over stimulation of nicotinic and muscarinic receptor by the lack of acetylcholine breakdown

• Soman half-life is
82 hours at pH 7.0,
20 C
• Liquid and gaseous forms are odorless and colorless
• Can be absorbed through the skin but generally considered nonpersistent

• Evidence of sarin usage by Iraq in
1988 against
Kurdish villages in northern Iraq.
• Odorless and colorless chemical can be absorbed through the skin, non-persistent
• 1995 Tokyo Sarin attack by Aum
Shinrikyo religious cult

• Most potent chemical nerve agent with highest dermal absorption rate
• Chemical is odorless and colorless gas
• VX droplets would remain on shrubbery or other surface for about a week. In the absence of sunlight, toxicant has a half-life of 996 hours, pH 7, 25 C.

• Eye: Miosis, dim vision or blurred vision
• Nose: Rhinorrhea
• Mouth: Excessive salivation
• Pulmonary tract: Bronchoconstriction and secretions, cough, complaints of tight chest, shortness of breath
• Gastrointestinal: increase secretions, vomiting, diarrhea, abdominal cramps, pain
• Skin: Excess sweating
• Muscular: twitching of muscle groups, flaccid paralysis, twiching
• Cardiovascular: decrease or increase in heart rate
• Central nervous system: loss of consciousness, convulsions, depression of respiratory center to produce apnea, coma

• Atropine (muscarinic cholinergic antagonist) is the standard treatment applied individuals showing symptoms of sweating, dilation of the pupil and salivation.
Intravenous application of atropine is administered every 20-30 minutes until symptoms disappear. In addition, Pralidoxime administration (2PAM-Cl) has also been indicated.
• Prophylactic deployed during the Persian Gulf
War consisted of pyridostygmine-bromine compounds

• Generally all chemical agents noted are susceptible to hypochlorite treatment. For environmental decontamination consider
10% hyperchlorite application. For skin,
0.5% hyperchlorite application has been suggested.
• Note that for chlorine and G-agents are generally too volatile to remain on the skin long enough to allow absorption of much of the deposited dose and are too polar to penetrate the skin well. However, if agent is placed on clothing and covered it would penetrate the skin.

• Cyanide, Mustard gas, Soman, Sarin and VX gases are difficult to handle due to the low vapor pressure and susceptibility to environmental conditions
• Open spaces with wind influence will quickly dilute toxic gases (except for VX) and most agents are susceptible to ultraviolet light inactivation over time. The problem are closed spaces such as buildings, gyms, convention halls.
These areas require physical decontamination or increased ventilation actions. Note: VX always requires inactivation for the environmental surroundings.
• Deployment would not involve an conventional explosive device but rather a pressure cylinder mechanism or glass container release in the HVAC intake for silent aerosol exposure

50
• Hydrogen cyanide 2500 to 5000 mg x min per cubic meter
• Sarin 100 mg x min per cubic meter
• Soman 50 mg x min per cubic meter
• VX 10 mg x min per cubic meter
• Unlike toxins, Sarin, Soman, VX, should not be treated with soap and water for skin exposure instead use 0.5% hypochlorite solution if available. Skin absorption too quick.

•
Botulinum Toxin
– Most potent toxin known to man
– Toxin is produced by a bacteria
• Ricin Toxin
– Recent events involving ricin
– Toxin is produced by a plant
• T-2 Mycotoxins
– Difficult to detect (not recognized by M8 paper or
M256 kit used for Mustard gases
– Toxin is produced by a fungus

• Clostridium botulinum
• Anaerobic, gram positive, rod shaped bacteria
• Food poisoning cases
• LD50 is 0.001 ug/kg, most potent toxin known to man
• FDA approved
Botox
• http://microvet.arizona.edu/Courses/MIC420/l ecture_notes/clostridia/clostridia_neurotox/gr am_c_botulinum.html

• Ptosis, generalized weakness, dizziness, dry mouth and throat, blurred vision and diplopia, dysarthria, dysphonia, and dysphagia followed by symmetrical descending flaccid paralysis and development of respiratory failure. Symptoms begin as early as 24-36 hours but may take several days after inhalation of toxin.

• Treatment: Intubation and ventilatory assistance for respiratory failure.
Tracheostomy may be required.
Administration of heptavalent botulinum antitoxin (IND product) may prevent or decrease progression to respiratory failure and hasten recovery.

Botulinum Toxin:
Decontamination and Isolation
• Standard Precautions for healthcare workers. Toxin is not dermally active and secondary aerosols are not a hazard from patients. Hypochlorite (0.5% for
10-15 minutes) and/or soap and water.

Differences between chemical nerve agents and Botulinum toxin
Chemical Agent
Minutes
Convulsions,
Muscle twitching
Ocular: Small pupils
Atropine/2-PAM-Cl responsive
Botulinum toxin
Hours (12-48)
Progressive paralysis
Ocular: Large pupils
Atropine/2-PAM-Cl: no effect

• Seed color varies from white to brown with wave patterns http://waynesword.palomar.e
du/plmar99.htm#flow

• Worldwide one million tons of castor beans are processed annually in the production of castor oil (waste mash is ~5% ricin by weight)
• Castor oil used as a mechanical lubricate, contains no ricin http://museum.gov.ns.ca/poison/cas tor1.htm

• Ricin is a heterodimeric protein toxin,
64Kd.
• The ricin A chain is able to cross the membrane of intracellular compartments to reach the cytosol where it catalytically inactivates protein synthesis. It is linked via a disulfide bond to the B chain, a galactose-specific lectin, which allows ricin binding at the cell surface and endocytosis.
• Cancer and autoimmune treatment applications

• Assassination of Bulgarian exile
Georgi Markov in London (1978)
• Minnesota Patriots Council
(1994 and 1995) and Thomas
Leahy, Wisconsin (1997)
• Deborah Green, Kansas (1995)
• al Qaeda cell, London (2003)

• Potent protein and DNA synthesis inhibitor
• LD50 for mice is 3.0 ug/kg
• Comparative lethality: LD50 for
Botulinum toxin (bacterium) is 0.001 and for VX gas (chemical agent) is
15.0
• LD50 for humans is uncertain and varies with route of entry (ricin vs ricinine)

• Ricin is environmentally stable with
3 day survival in dry conditions
• No person to person transmission
• Lethality is high with death occurring
10-12 days for ricin ingestion and 3-4 days for inhalational exposure

• Gold Standard technique is enzyme linked immunosorbent assays (ELISA)
-antigen detection
-IgG immunoassay
-IgM immunoassay

• There is currently no commercial vaccine or prophylactic antitoxin available for human use albeit animal immunization studies have been promising
• Protective mask and engineering controls are currently the best protection

• 4 to 8 hours: Acute onset of fever, chest tightness, cough, dyspnea, nausea and arthralgias
• 18-24 hours: Airway necrosis and pulmonary capillary leak leading to pulmonary edema
• 36-72 hours: severe respiratory distress and death from hypoxemia

• Early Post-exposure (0-24 h): nasal swabs, induced respiratory secretions for PCR (contaminating castor bean DNA) and Serum for toxin assays
• Clinical (36-48 h): serum for toxin assay and tissues for immunohistological stain in pathology samples
• Postmortem (>6 days): Serum for
IgM and IgG

• Ingestional entry: Gastric lavage and cathartics are indicated. Charcoal application is of little value for large molecules such as ricin
• Inhalation entry: Pulmonary edema treatment and supportive management

• Ricin inactivation can be accomplished with bleach (1% sodium hypochlorite, 20 min) or autoclave treatment (80C for 10 min)
• Intact skin surface decontamination use soap and water (dilution).

• Trichothecene (T-2) mycotoxins produced by the fungi of genus
Fusarium (common grain mold)
• Extremely stable in the environment
• Toxin is dermally active causing blisters (minutes to hours after exposure)

• Shortly after WWII, flour contaminated with Fusarium unknowingly baked into bread and ingested by civilians. Exposed individuals developed a protracted lethal illness called alimentary toxic aleukia (ATA).
• “Yellow rain” incidents in Laos (1975-
81), Kampuchea (1979-81) and
Afghanistan (1979-81).

• Trichothecene are relatively insoluble in water
• Compounds are extremely stable to heat and ultraviolet light inactivation
• Bioactivity retained even after standard autoclaving (inactivation requires 1500 F for 30 minutes)
• Hypochlorite solution alone does not inactive the toxins
• Toxin rapidly inhibit protein and nucleic acid synthesis

• Routes of exposure: penetration through the skin, inhalation and ingestion.
• Contaminated clothing can serve as a reservoir for further toxin exposure
• Early symptoms (minutes after skin exposure): burning skin, redness, tenderness, blistering and progression to skin necrosis with leathery blackening and sloughing of large areas of the skin
• Pulmonary/tracheobronchial toxicity produces dyspnea, wheezing and cough.
• Gastrointestinal toxicity causes pain and blood tinged saliva and sputum
• Death may occur in minutes, hours or days
• Most common symptoms: vomiting, diarrhea, skin involvement with burning pain, redness, rash or blisters, bleeding and dyspnea.

• Physical clues yellow, red, green or other pigmented oily liquid
• Contact with the skin (unlike ricin) forms characteristic symptoms
• Generally considered odorless
• Serum and urine should be collected to be sent to a reference lab for antigen detection (gas liquid chromatography-mass spectrometry technique)

• Toxin inactivation requires 0.1M NaOH added to 1% hypochlorite solution for a duration of one hour.
• No specific antidote or therapeutic regimen is currently available.
• Exposed individuals: remove clothing, wash skin with soap and water.
• Standard burn care is indicated for cutaneous involvement
• Toxin ingestion use superactivated charcoal
• Aerosol attack: respiratory support may be required, rinse out eyes with saline or water.
• Only physical protection of the skin, mucous membranes and airway are the only proven effective methods of protection during an attack.

• Klaassen, Curtis D. (1996) Casarett and
Doull’s Toxicology, The Basic Science of
Poisons, fifth edition. The McGraw-Hill
Companies, Inc.
• Somani, Satu M. (1992) Chemical Warfare
Agents, Academic Press, Inc.
• Satellite Broadcast September 26-28, 2000
Biological Warfare and Terrorism, Medical
Issues and Response (Student Material
Booklet). Sponsored by the United States
Army Medical Research Institute of
Infectious Diseases and the Food and Drug
Agency

Gulf War Syndrome Research
UT Southwestern: Department of
Epidemiology
• Christopher Sinton, PhD.
• Robert Haley, MD.
Ricin Research Endeavors
UT Southwestern: Cancer Immunobiology
Center
• Joan Smallshaw, PhD.
• Ellen Vitetta, PhD.