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Material Safety Data Sheet -- Lethal Nerve Agent Tabun (GA)

Section I: General Information
Section II: Composition
Section III: Physical Data
Section IV: Fire and Explosion Data
Section V: Health Hazard Data
Section VI: Reactivity Data
Section VII: Spill, Leak and Disposal Procedures

Section I: General Information

MANUFACTURER'S NAME: Department of the Army

MANUFACTURER'S ADDRESS:

U.S. Army Armament, Munitions and Chemical Command
Chemical Research, Development and Engineering Center
ATTN: SMCCR-CMS-E
Aberdeen Proving Ground, MD 21010-5423

CAS REGISTRY NUMBER: None

CHEMICAL NAME: Ethyl N,N-dimethylphosphoramidocyanidate

TRADE NAME AND SYNONYMS:

CHEMICAL FAMILY: Organophosphorous compound

FORMULA: C5 H11 N2 02 P

NFPA 704 SIGNAL:

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Section II: Composition

INGREDIENTS     FORMULA       PERCENTAGE     AIRBORNE
      NAME                    BY WEIGHT      EXPOSURE LIMIT (AEL)

      GA      C5 H11 N2 02 P     100         0.0001 mg/m3

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Section III: Physical Data

BOILING POINT DEG F (DEG C): 247.5 DEG C

VAPOR PRESSURE (mm hg): 0.07 @ 24 DEG C

VAPOR DENSITY (AIR=1): 5.6

SOLUBILITY IN WATER (g/100 g): 9.8 @ 25 DEG C/ 7.2 @ 20 DEG C

SPECIFIC GRAVITY (H20=1): Not available

FREEZING (MELTING) POINT: -50 DEG C

AUTOIGNITION TEMPERATURE DEG F (DEG C): Not available

VISCOSITY (CENTISTOKES): 2.18 @ 25 DEG C

PERCENTAGE VOLATILE BY VOLUME: 610 mg/m3 @ 25 DEG C

EVAPORATION RATE: Not available

APPEARANCE AND ODOR: Colorless to brown liquid. Faintly fruity; none when pure

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Section IV: Fire and Explosion Data

FLASHPOINT: 78 DEG C

FLAMMABILITY LIMITS (% by volume): Not available

EXTINGUISING MEDIA: Water, fog, foam, CO2 - Avoid using extinguishing methods that will cause splashing or spreading of the GA.

UNUSUAL FIRE & EXPLOSION HAZARDS: Fires involving this chemical may result in the formation of hydrogen cyanide.

SPECIAL FIRE FIGHTING PROCEDURES:

All persons not engaged in extinguishing the fire should be immediately evacuated from the area. Fires involving GA should be contained to prevent contamination to uncontrolled areas. When responding to a fire alarm in buildings or areas containing agents, firefighting personnel should wear full firefighter protective clothing (without TAP clothing) during chemical agent firefighting and fire rescue operations.

Respiratory protection is required. Positive pressure, full facepiece, NIOSH-approved self- contained breathing apparatus (SCBA) will be worn where there is danger of oxygen deficiency and when directed by the fire chief or chemical accident/incident (CAI) operations officer. The M9 or M17 series mask may be worn in lieu of SCBA when there is no danger of oxygen deficiency. In cases where firefighters are responding to a chemical accident/incident for rescue/reconnaissance purposes vice firefighting, they will wear appropriate levels of protective clothing (see Section 8).

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Section V: Health Hazard Data

AIRBORNE EXPOSURE LIMIT (AEL): The suggested permissible airborne exposure concentration for GA for an 8-hour workday or a 40 hour work week is an 8 hour time weight average (TWA) of 0.0001 mg/m3 (2 x 10-5 ppm). This value is based on the TWA of GA as proposed in the USaEHA Technical Guide 169, "Occupational Health Guildelines for the Evaluation and Control of Occupational Exposure to Nerve Agents, GA, GB, GD, and VX." To date, however, the Occupational Safety and Health Administration (OSHA) has not promulgated a permissible exposure concentration for GA.

EFFECTS OF OVEREXPOSURE:

GA is an anticholinesterase agent similar in action to GB. Although only about half as toxic as GB by inhalation, GA in low concentrations is more irritating to the eyes than GB.

The number and severity of symptoms which appear are dependent on the quantity, and rate of entry of the nerve agent which is introduced into the body. (Very small skin dosages sometimes cause local sweating and tremors with few other effects.)

Individuals poisoned by GA display apaproximately the same sequence of symptoms regardless of the route by which the poison enters the body (whether by inhalation, absorption, or ingestion). These symptoms, in normal order of appearance, runny nose; tightness of chest; dimness of vision and pin pointing of the eye pupils; difficulty in breathing; drooling and excessive sweating; nausea; vomiting, cramps, and involuntary defecation and urination; twitching, jerking, and staggering; and headaches, confusion, drowsiness, coma, and convulsion. These symptoms are followed by cessation of breathing and death.

Onset Time of Symptoms: Symptoms appear much more slowly from skin dosage than from respiratory dosage. Although skin absorption great enough to cause death may occur in 1 to 2 minutes, death may be delayed for 1 to 2 hours. Respiratory lethal dosages kill in 1 to 10 minutes, and liquid in the eye kills almost as rapidly.

Median Lethal Dosage, Animals: LD50 (monkey, percutaneous) = 9.3 mg/kg (shaved skin); LCt50 (monkey, inhalation) = 187 mg-min/m3 (t = 10)

Median Lethal Dosage, Man: LCt50 (man, inhalation) = 135 mg-min/m3 (t = 0.5-2 min) at RMV (Respiratory Minute Volume) of 15 1/min; 200 mg-min/m3 at RMV* of 10 1/min

GA is not listed by the International Agency for Research on Cancer (IARC), American Conference of Governmental Industrial Hygienists (ACGIH). Occupational Safety and Health Administration (OSHA), or National Toxicology Program (NTP) as a carcinogen.

EMERGENCY AND FIRST AID PROCEDURES:

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Section VI: Reactivity Data

STABILITY: Stable

INCOMPATIBILITY: Not available

HAZARDOUS DECOMPOSITION: Decomposes within 6 months at 60 DEG C. Complete decomposition in 3-1/4 hours at 150 DEG C. May produce HCN. Oxides of nitrogen, oxides of phosphorus, carbon monoxide, and hydogen cyanide.

HAZARDOUS POLYMERIZATON: Not available

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Section VII: Spill, Leak and Disposal Procedures

STEPS TO BE TAKEN IN CASE MATERIAL IS RELEASED OR SPILLED: If leaks or spills occur, only personnel in full protective clothing (see section 8) will remain in area. In case of personnel contamination see section V "Emergency and First Aid Instructions."

RECOMMENDED FIELD PROCEDURES:

Spills must be contained by covering with vermiculite, diatomaceious earth, clay, fine sand, sponges, and paper or cloth towels. This containment is followed by treatment with copious amounts of aqueous Sodium Hydroxide solution (a minimum 10 wt percent). Scoop up all material and place in a fully removable head drum with a high density polyethylene liner. The decontamination solution must be treated with excess bleach to destroy the CN formed during hydrolysis. Cover the contents with additional bleach before affixing the drum head. After sealing the head, the exterior of the drum shall be decontaminated and then labeled IAW EPA and DOT regulations.

All leaking containers shall be overpacked with vermiculite placed between the interior and exterior containers. Decontaminate and label IAW EPA and DOT regulations. Dispose of the material IAW waste disposal methods provided below. Conduct general area monitoring with an approved monitor (see Section 8) to confirm that the atmospheric concentrations do not exceed the airborne exposure limit (see Sections 2 and 8).

If 10 wt percent Sodium Hydroxide is not available then the following decontaminants may be used instead and are listed in order of preference: Decontamination Solution No. 2 (DS2), Sodium Carbonate and Supertropical Bleach Slurry (STB).

RECOMMENDED LABORATORY PROCEDURES:

A minimum of 56 grams of decon solution is required for each gram of GA. The decontamination solution is agitated while GA is added and the agitation is maintained for at least one hour. The resulting solution is allowed to react for 24 hours. At the end of 24 hours, the solution must be tritrated to a pH between 10 and 12. After completion of the 24 hour period, the decontamination solution must be treated with excess bleach (2.5 mole OC1-/mole GA) to destroy the CN formed during hydrolysis.

Scoop up all material and place in a fully removable head drum with a high density polyethylene liner. Cover the contents with additional bleach before affixing the drum head. All contaminated clothing will be placed in a fully removable head drum with a high density polyethylene liner. Cover the contents of the drum with decontaminating solution as above before affixing the drum head. After sealing the head, the exterior of the drum shall be decontaminated and then labeled IAW state, EPA and DOT regulations.

All leaking containers shall be overpacked with vermiculite placed between the interior and exterior containers. Decontaminate and label IAW State, EPA and DOT regulations. Conduct general area monitoring with an approved monitor (see Section 8) to confirm that the atmospheric concentrations do not exceed the airborne exposure limit (see Sections 2 and 8).

WASTE DISPOSAL METHOD: Open pit burning or burying of GA or items containing GA.

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