PAN Pesticides Database - Chemicals

Methidathion - Identification, toxicity, use, water pollution potential, ecological toxicity and regulatory information

Note: See Working with the Information on this Page section below for important notes about this data.

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Identifying information, including synonyms, ID numbers, use type, chemical classification, a link to a list of all products containing this chemical and a list of the top crops this pesticide is used on in California.
Signs and symptoms of poisoning, first aid, and links to treatment information for this chemical.
Link to information on toxicity to humans, including carcinogenicity, reproductive and developmental toxicity, neurotoxicity, and acute toxicity.
Links to world-wide registration status as well as regulatory information for the U.S. and California.
Water quality standards and physical properties affecting water contamination potential.
Toxicity to aquatic organisms.
List of chemicals in the same family, including breakdown products, salts, esters, isomers, and other derivatives.
 

Chemical Identification and Use for Methidathion

Basic Identification Information About This Chemical
Chemical Name: Methidathion
CAS Number: 950-37-8
U.S. EPA PC Code: 100301
CA DPR Chem Code: 1689
Molecular Weight: 302.3
Molecular Structure:
Use Type: Insecticide
Chem Class: Organophosphorus
View Related Chemicals
 
Additional Resources About This Chemical Class and Use Type
Historical Use of this Chemical
Top five crops and sites for this pesticide in California
Safflower   Artichokes   Apples   Alfalfa for Forage   Prunes  
View All Crops and Sites
 
Other Names for this Chemical
About Chemical Synonyms
(US EPA PC Code ) , 100301 (US EPA PC Code Text ) , 1689 (CA DPR Chem Code) ) , 197 (PDP Code) , 950-37-8 (CAS number) , 950378 , 950378 (CAS number without hyphens) , ENT 27193 , GS 13005 , Methedathion , Methidathion , Methidathion (ANSI) , METHIDATHION (CA DPR Chem Code Text ) , Metidation , Metidationa , Metidati?o , Nethidathion , O,O-Dimethyl phosphorodithioate, S-ester with 4-(mercaptomethyl)-2-methoxy-delta(superscript 2)-1,3,4-thiadiazolin-5-one , Phosphorodithioic acid S-[(5-methoxy-2-oxo-1,3,4-thiadiazol-3(2H)yl)methyl] O,O-dimethyl ester , Phosphorodithioic acid, S-((5-methoxy-2-oxo-1,3,4-thidadiazol-3(2H)-yl)methyl) O,O-dimethyl ester , S-((5-Methoxy-2-oxo-1,3,4-thiadiazol-3(2H)-yl)methyl) O,O-dimethyl phosphorodithioate , Somonil , Supracide , Suprathion , Ultracide
 
Products Containing This Chemical
Current and historic U.S. registered products
View U.S. Products All Products Currently Registered Products
 

Signs and Symptoms of Methidathion Poisoning

NOTE! There may be other diseases and chemicals that have similar symptoms.

If you have a poisoning emergency in the United States call 1-800-222-1222.
If the victim has collapsed or is unconscious, call 911.

Methidathion is a Organophosphorus compound.

Report a Poisoning

Symptoms of Poisoning with Organophosphorus Compounds
Find Products Containing this Chemical

- Excessive salivation, sweating, rhinorrhea and tearing.
- Muscle twitching, weakness, tremor, incoordination.
- Headache, dizziness, nausea, vomiting, abdominal cramps, diarrhea.
- Respiratory depression, tightness in chest, wheezing, productive cough, fluid in lungs.
- Pin-point pupils, sometimes with blurred or dark vision.
- Severe cases: seizures, incontinence, respiratory depression, loss of consciousness.
- Cholinesterase inhibition.

Source for Group Symptoms: Recognition and Management of Pesticide Poisoning, 5th edition, U.S. EPA, Chapter 4.

Treatment for Organophosphorus Poisoning

See: Recognition and Management of Pesticide Poisoning, 5th edition, U.S. EPA, Chapter 4, page 40.

 
Symptoms of Methidathion Exposure

Effects due to acute methidathion exposures are similar to those caused by other organophosphate pesticides.
- Mild skin irritation.
- Nausea, vomiting, cramps, diarrhea, salivation, headache, dizziness, muscle twitching, difficulty breathing, blurred vision, and tightness in the chest.
- High acute exposure may cause intense breathing problems, including paralysis of the respiratory muscles.

Source for Symptoms: Extension Toxicology Network (EXTOXNET), Oregon State University, June 1996. (ExToxNet)

First Aid for Methidathion Poisoning

For Inhalation
- Move victims to fresh air. Emergency personnel should avoid self-exposure to methidathion. Evaluate vital signs including pulse and respiratory rate, and note any trauma. If no pulse is detected, provide CPR. If not breathing, provide artificial respiration. If breathing is labored, administer 100% humidified oxygen or other respiratory support.
- Obtain authorization and/or further instructions from the local hospital for administration of an antidote or performance of other invasive procedures. Rush to a health care facility.
For Skin and Eyes
- Remove victims from exposure. Emergency personnel should avoid self-exposure to methidathion. Evaluate vital signs including pulse and respiratory rate, and note any trauma. If no pulse is detected, provide CPR. If not breathing, provide artificial respiration. If breathing is labored, administer 100% humidified oxygen or other respiratory support.
- Remove contaminated clothing as soon as possible. If eye exposure has occurred, eyes must be flushed with lukewarm water for at least 15 minutes. Wash exposed skin areas three times with soap and water. Obtain authorization and/or further instructions from the local hospital for administration of an antidote or performance of other invasive procedures. Rush to a health care facility.
For Ingestion
- Evaluate vital signs including pulse and respiratory rate, and note any trauma. If no pulse is detected, provide CPR. If not breathing, provide artificial respiration. If breathing is labored, administer 100% humidified oxygen or other respiratory support. Obtain authorization and/or further instructions from the local hospital for administration of an antidote or performance of other invasive procedures. Vomiting may be induced with syrup of Ipecac. If elapsed time since ingestion of methidathion is unknown or suspected to be greater than 30 minutes, do not induce vomiting and proceed to Step 4. Ipecac should not be administered to children under 6 months of age.
- Warning: Ingestion of methidathion may result in sudden onset of seizures or loss of consciousness. Syrup of Ipecac should be administered only if victims are alert, have an active gag-reflex, and show no signs of impending seizure or coma. If ANY uncertainty exists, proceed to Step 4. The following dosages of Ipecac are recommended: children up to 1 year old, 10 mL (1/3oz); children 1 to 12 years old, 15mL (1/2oz); adults, 30mL (1 oz). Ambulate (walk) the victims and give large quantities of water. If vomiting has not occurred after 15 minutes, Ipecac may be read ministered. Continue to ambulate and give water to the victims. If vomiting has not occurred within 15 minutes after second administration of Ipecac, administer activated charcoal.
- Activated charcoal may be administered if victims are conscious and alert. Use 15 to 30g (1/2 to 1oz) for children, 50 to 100g (1-3/4 to 3-1/2oz) for adults, with 125 to 250mL (1/2 to 1 cup) of water. Promote excretion by administering a saline cathartic or sorbitol to conscious and alert victims. Children require 15 to 30 g (1/2 to 1 oz) of cathartic; 50 to 100g (1-3/4 to 3-1/2oz) is recommended for adults. Rush to a health care facility.
Get medical aid.

Source for First Aid: Emergency First Aid Treatment Guide, U.S. Enviromental Protection Agency, Washington, D.C. July 2003. (US EPA Other)

 
 

Toxicity Information for Methidathion

  Note: Information for many chemicals is incomplete and may not be fully representative of effects on humans. Why?

Summary Toxicity Information

PAN Bad Actor
Chemical
1
Acute
Toxicity
2
Carcinogen Cholinesterase
Inhibitor
Ground
Water Contaminant
Developmental or
Reproductive Toxin
Endocrine
Disruptor
Possible
Potential
 
Indicates high toxicity in the given toxicological category. Indicates no available weight-of-the-evidence summary assessment. For additional information on toxicity from scientific journals or registration documents, see the "Additional Resources for Toxicity " section of the chemical detail page.
1. PAN Bad Actors are chemicals that are one or more of the following: highly acutely toxic, cholinesterase inhibitor, known/probable carcinogen, known groundwater pollutant or known reproductive or developmental toxicant. NOTE! Because there are no authoritative lists of Endocrine Disrupting (ED) chemicals, EDs are not yet considered PAN Bad Actor chemicals.
2. The acute toxicity reported on this page is of the pure chemical ingredient only and may not reflect the acute toxicity of individual pesticide products. To view acute toxicity of individual products, click on 'View Products' link in the 'Chemical Identification' section above.

Detailed Toxicity Information

Acute Toxicity 2
Methidathion
WHO Acute Hazard
TRI Acute Hazard
Material Safety Data Sheets
Acute rating from U.S. EPA product label
U.S. NTP Acute Toxicity Studies
      View Studies
Cholinesterase Inhibitor
Ib, Highly Hazardous
Not Listed
Not Available
Highly Toxic
No NTP Studies

Yes
2. The acute toxicity reported on this page is of the pure chemical ingredient only and may not reflect the acute toxicity of individual pesticide products. To view acute toxicity of individual products, click on 'View Products' link in the 'Chemical Identification' section above.
 
Cancer Information
Methidathion
IARC Carcinogens
U.S. NTP Carcinogens
California Prop 65 Known Carcinogens
U.S. EPA Carcinogens
TRI Carcinogen
Not Listed
Not Listed
Not Listed
C, Possible
Not Listed
 
Endocrine Disruption
Methidathion
Illinois EPA list
Keith list
Colborn list
Benbrook list
Danish Inert list
EU list
Not Listed
Not Listed
Not Listed
Not Listed
Not Listed
Not Listed
 
Reproductive and Developmental Toxicity
Methidathion
CA Prop 65 Developmental Toxin
U.S. TRI Developmental Toxin
CA Prop 65 Female Reproductive Toxin
CA Prop 65 Male Reproductive Toxin
U.S. TRI Reproductive Toxin
Not Listed
Not Listed
Not Listed
Not Listed
Not Listed
 
Chemicals of Special Concern
Methidathion
PAN Bad Actors
PAN Dirty Dozen list
Yes
Not Listed
 

Water Pollution Potential and Criteria for Methidathion

Water Pollution Potential

PAN Ground Water Contaminant Rating Potential
 
Physical Property Data Related to Water Contamination Potential
Water Solubility (Avg, mg/L)
Adsorption Coefficient (Koc)
Hydrolysis Half-life (Avg, Days)
Aerobic Soil Half-life (Avg, Days)
Anaerobic Soil Half-life (Avg, Days)
221.0
341.0
26.0
3.00
-
 
 

Sorry, no water quality standards or criteria have been established for this chemical by the U.S. or Canadian governments; however, there may be criteria established for related chemicals.

 

Regulatory Information for Methidathion

International Regulatory Status

 
UNEP Persistent Organic Pollutant (POP)
UNEP Prior Informed Consent Chemical (PIC)
WHO Obsolete Pesticide
Not Listed
Not Listed
Not Listed
 

U.S. and California Regulatory Status

U.S. EPA Registered
U.S. EPA Hazardous Air Pollutant
U.S. EPA Minimum Risk Pesticide (25b list)

CA Registered
CA Groundwater Contaminant
CA Toxic Air Contaminant
Yes
Not Listed
No

Yes
Not Listed
TAC
 

Maximum Tolerance and Residue Levels

Codex Alimentarius
   (UN FAO Maximum Residue Limits)
U.S. Maximum Tolerance Levels
European Union Maximum Residue Levels
Go to web site

Go to web site

Go to web site
 

Ecotoxicity for Methidathion

Note! Information for many chemicals is incomplete and may not be fully representative of effects on the environment. Why? Click on underlined terms for definitions and additional information.

Aquatic Ecotoxicity

All Toxic Effects for Organism Group
Organism Group Effects Noted
Crustaceans Mortality
Fish Accumulation, Biochemistry, Enzyme(s), Histology, Mortality, Physiology
Insects Behavior, Mortality, Population
Molluscs Accumulation, Behavior, Intoxication, Mortality
Zooplankton Intoxication, Mortality
~ Un-Assigned Mortality
View All Aquatic Ecotoxicity Studies and References
 
Summary of Acute Toxicity for Organism Group
Organism Group Average Acute Toxicity Acute Toxicity Range
Crustaceans Highly Toxic High to Very High Toxicity
Fish Moderately Toxic Slight to Very High Toxicity
Insects Very Highly Toxic Very Highly Toxic
Molluscs Slightly Toxic Slight to Moderate Toxicity
Zooplankton Slightly Toxic Slight to Very High Toxicity
~ Un-Assigned Very Highly Toxic Very Highly Toxic
View All Acute Summaries
 

Terrestrial Ecotoxicity

Summary of Acute Toxicity for Organism Group
Organism Group Average Acute Toxicity Acute Toxicity Range
HoneybeesHighly ToxicHighly Toxic
Note: Population-level effects on honeybees may occur even if a pesticide has low acute toxicity. For example, certain pesticides interfere with honeybee reproduction, ability to navigate, or temperature regulation, any of which can have an effect on long-term survival of honeybee colonies. The neonicotinoids, pyrethroids and keto-enol pesticides are some types of pesticides causing one or more of these effects.
Honeybee Chronic Toxicity

Sorry, no honeybee chronic toxicity data available for this chemical. Try related chemicals.

Related Chemicals for Methidathion

CAS Number Relation Reason Chemical Name Chem Detail Symptoms California Use Chem Use Type U.S. EPA Reg PAN Bad Actor
950-37-8 Parent P Methidathion View View View Insecticide Yes Yes
Related 5b Methidathion OA View View View Insecticide No Yes
 
Working with the Information on this Page

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* Data marked with an asterisk indicates that this chemical is not explicitly listed on the corresponding list. Instead, it belongs to a group of chemicals that IS designated on the list. For example, if an agency assigns a classification of reproductive toxicant to "mercury compounds", that classification is applied to all mercury compounds in the PAN Pesticide database, which are then marked with an asterisk.

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