EMPTA

  • O-Ethyl methylphosphonothioate
Formula
C3H9O2PS
Structure
Description
Colorless to straw colored liquid. Odorless.
Uses
Lethal nerve agent.

Registry Numbers and Inventories.
CAS
18005-40-8
23/24/25-34
23-26-36/37/39-45
UN (DOT)
2810
Merck
12,10496
Beilstein/Gmelin
1747379
Beilstein Reference
4-04-00-03514

Properties.
Formula
C3H9O2PS
Formula mass
140.14
Boiling point, °C
153
Vapor pressure, mmHg
4 (25 C)
Vapor density (air=1)
9.2
Density
1.1735 g/cm3 (25 C)
Solubility in water
Soluble
Refractive index
1.4912 (25 C)
pKa/pKb
3.87 (pKa)
Heat of vaporization
37.4 kJ/mol

Hazards and Protection.
Protection
Butyl rubber gloves and chemical safety goggles.
Respirators
A full face piece, chemical canister, air-purifying protective mask will be on hand for escape. (The M9-, M17-, or M40-series masks are acceptable for this purpose Other masks certified as equivalent may be used.
Small spills/leaks
If leaks or spills occur, only personnel in full protective clothing will remain in area. Do not attempt to deal with any spill or leak until directed by a qualified risk manager.
Stability
Stable at normal temperatures and pressures.

Fire.
Flash Point,°C
46
Fire fighting
Water mist, fog, foam, CO2. Avoid using extinguishing methods that will cause splashing. All persons not engaged in extinguishing the fire should be immediately evacuated from the area. re fighting 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 face piece, NIOSH-approved self-contained breathing apparatus (SCBA) will be worn where there is danger of oxygen deficiency and when directed by the fire chief of chemical accident/incident (CAI) operations officer. In cases where firefighters are responding to a chemical accident/incident for rescue/reconnaissance purposes they will wear appropriate levels of protective clothing.
Hazards
Do not breathe fumes. Skin contact with nerve agents must be avoided at all times. Although the fire may destroy most of the agent, care must still be taken to assure the agent or contaminated liquids. Do not further contaminate other areas or sewers. Contact with liquid or vapors can be fatal

Health.
Exposure effects

First aid
 
   Ingestion
Do not induce vomiting. First symptoms are likely to be gastrointestinal. IMMEDIATELY administer Nerve Agent Antidote Kit, Mark I. Seek medical attention IMMEDIATELY
   Inhalation
Hold breath until respiratory protective mask is donned. If severe signs of agent exposure appear (chest tightens, pupil constriction, incoordination, etc.), immediately administer, in rapid succession, all three Nerve Agent Antidote Kit(s), Mark I injectors (or atropine if directed by physician). Injections using the Mark I kit injectors may be repeated at 5 to 20 minute intervals if signs and symptoms are progressing until three series of injections have been administered. No more injections will be given unless directed by medical personnel. In addition, a record will be maintained of all injections given. If breathing has stopped, give artificial respiration. Mouth-to-mouth resuscitation should be used when approved mask-bag or oxygen delivery systems are not available. Do not use mouth-to-mouth resuscitation when facial contamination exists. If breathing is difficult, administer oxygen. Seek medical attention IMMEDIATELY
   Skin
Don respiratory protective mask and remove contaminated clothing. Immediately wash contaminated skin with copious amounts of soap and water, 10% sodium carbonate solution, or 5% liquid household bleach. Rinse well with water to remove excess decontaminant. Administer nerve agent antidote kit, Mark I, only if local sweating and muscular twitching symptoms are observed. Seek medical attention IMMEDIATELY.
   Eyes
IMMEDIATELY flush eyes with water for 10-15 minutes, then don respiratory protective mask. Although miosis (pinpointing of the pupils) may be an early sign of agent exposure, an injection will not be administered when miosis is the only sign present. Instead, the individual will be taken IMMEDIATELY to a medical treatment facility for observation.

Transport.
UN number
2810
Response guide
Hazard class
6.1
Packing Group
I