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METHIDATHION
ICSC: 1659
Peer-Review Status: 11.10.2006 Validated
O,O-Dimethyl S-(2,3-dihydro-5-methoxy-2-oxo-1,3,4-thiadiazol-3-ylmethyl) phosphorodithioate
O,O-Dimethyl-S-(5-methoxy-1,3,4-thiadiazolinyl-3-methyl) dithiophosphate 
CAS #: 950-37-8 RTECS #: TE2100000
UN #: 2783
EC #: 015-069-00-2
EINECS #: 213-449-4
    Formula: C6H11N2O4PS3
Molecular mass: 302.3

TYPES OF
HAZARD /
EXPOSURE
ACUTE HAZARDS / SYMPTOMS      PREVENTION      FIRST AID / FIRE FIGHTING
FIRE Combustible. Liquid formulations containing organic solvents may be flammable. Gives off irritating or toxic fumes (or gases) in a fire.  NO open flames.  Use water spray. Use dry powder. Use carbon dioxide. 
EXPLOSION      
 
EXPOSURE   PREVENT DISPERSION OF DUST!  IN ALL CASES CONSULT A DOCTOR! 
Inhalation Dizziness. Nausea. Sweating. Muscle twitching. Pupillary constriction, muscle cramp, excessive salivation. Laboured breathing. Convulsions. Unconciousness.  Use local exhaust or breathing protection.  Fresh air, rest. Artificial respiration may be needed. Refer immediately for medical attention. 
Skin MAY BE ABSORBED! See Inhalation.  Protective gloves. Protective clothing.  Remove contaminated clothes. Rinse and then wash skin with water and soap. Refer immediately for medical attention. Wear protective gloves when administering first aid. 
Eyes Blurred vision.  Wear face shield or eye protection in combination with breathing protection.  First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then refer for medical attention. 
Ingestion Abdominal cramps. Diarrhoea. Vomiting. Further see Inhalation.  Do not eat, drink, or smoke during work. Wash hands before eating.  Rinse mouth. Give a slurry of activated charcoal in water to drink. Refer immediately for medical attention. 

SPILLAGE DISPOSAL
PACKAGING & LABELLING
Personal protection: complete protective clothing including self-contained breathing apparatus. Do NOT let this chemical enter the environment. Sweep spilled substance into covered sealable containers. Carefully collect remainder. Then store and dispose of according to local regulations.  Do not transport with food and feedstuffs.
Marine pollutant. 
EC Classification
Symbol: T+, N; R: 21-28-50/53; S: (1/2)-22-28-36/37-45-60-61 
UN Classification
UN Hazard Class: 6.1; UN Pack Group: II 
GHS Classification
Signal: Danger
Fatal if swallowed
Fatal in contact with skin
Fatal if inhaled
Causes damage to nervous system
Very toxic to aquatic life 
skull;toxiccancer;health hazenviro;aqua

EMERGENCY RESPONSE SAFE STORAGE
Transport Emergency Card: TEC (R)-(61GT7-II).  Provision to contain effluent from fire extinguishing. Separated from food and feedstuffs. Well closed. Store in an area without drain or sewer access. 

IMPORTANT DATA
Physical State; Appearance
COLOURLESS CRYSTALS. 

Physical dangers
 

Chemical dangers
Decomposes on heating. This produces toxic fumes. 

Occupational exposure limits
TLV (NOT-ESTABLISHED):. 

Routes of exposure
The substance can be absorbed into the body in hazardous amounts by inhalation, through the skin and by ingestion. 

Inhalation risk
A harmful concentration of airborne particles can be reached quickly when dispersed. 

Effects of short-term exposure
Cholinesterase inhibition. The substance may cause effects on the nervous system. This may result in convulsions and respiratory depression. Exposure could cause death. The effects may be delayed. Medical observation is indicated. 

Effects of long-term or repeated exposure
Cholinesterase inhibition. Cumulative effects are possible. See Acute Hazards/Symptoms. 


PHYSICAL PROPERTIES ENVIRONMENTAL DATA
Melting point: 39°C
Density: 1.5 g/cm³
Solubility in water, g/100ml at 20°C: 0.0187
Vapour pressure at 20°C: negligible
Flash point: 100°C
Octanol/water partition coefficient as log Pow: 2.2  
The substance is very toxic to aquatic organisms. This substance does enter the environment under normal use. Great care, however, should be taken to avoid any additional release, for example through inappropriate disposal. 

NOTES
Carrier solvents used in commercial formulations may change physical and toxicological properties.
Specific treatment is necessary in case of poisoning with this substance; the appropriate means with instructions must be available.
Do NOT take working clothes home.
Card has been partially updated in January 2008: see GHS classification. 

ADDITIONAL INFORMATION
 

IPCS
International
Programme on
Chemical Safety
WHO ILO EC Prepared in the context of cooperation between the International Programme on Chemical Safety and the European Commission
© IPCS 2004-2012
LEGAL NOTICE Neither the EC nor the IPCS nor any person acting on behalf of the EC or the IPCS is responsible for the use which might be made of this information.


    See Also:
       Toxicological Abbreviations
       Methidathion (WHO Pesticide Residues Series 2)
       Methidathion (WHO Pesticide Residues Series 5)
       Methidathion (Pesticide residues in food: 1979 evaluations)
       Methidathion (Pesticide residues in food: 1992 evaluations Part II Toxicology)
       Methidathion (Pesticide residues in food: 1997 evaluations Part II Toxicological & Environmental)