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Chemical Datasheet

METHYL THIOCYANATE

6.1 - Poison 3 - Flammable liquid

Chemical Identifiers

CAS Number UN/NA Number DOT Hazard Label USCG CHRIS Code
  • 556-64-9   (METHYL THIOCYANATE)
  • 2929
  • Poison
  • Flammable Liquid
none
NIOSH Pocket Guide International Chem Safety Card
none none
NFPA 704
data unavailable
General Description
Colorless liquid and an odor of onions. Used as an agricultural insecticide, a fumigant and as a research chemical. No evidence of commercial production in the U.S. (EPA, 1998)

Hazards

Reactivity Alerts
none
Air & Water Reactions
Very slightly soluble in water [Merck].
Fire Hazard
When heated to decomposition, it emits very toxic fumes of oxides of nitrogen and sulfur. (Non-Specific -- Thiocyanates) Incompatible with nitric acid. Violent reactions have occurred when mixed with chlorates, nitrates, nitric acid, organic peroxides, peroxides, potassium chlorate, and sodium chlorate. This material is volatile. (EPA, 1998)
Health Hazard
This material is highly toxic if ingested. It is a rapidly acting poison. (EPA, 1998)
Reactivity Profile
METHYL THIOCYANATE is a moderately toxic liquid, flammable. Violent, possibly explosive oxidation reaction when mixed with chlorates, nitrates, nitric acid, organic or inorganic peroxides, perchlorates. On contact with mineral acids or acid fumes deadly toxic hydrogen cyanide gas is produced. When heated to decomposition or on contact with mineral acids it emits highly toxic fumes of nitriles, oxides of sulfur and nitrogen [Lewis, 3rd ed., 1993, p. 879, 1234].
Belongs to the Following Reactive Group(s)
Potentially Incompatible Absorbents

Use caution: Liquids with this reactive group classification have been known to react with the absorbents listed below.

Response Recommendations

Isolation and Evacuation
Excerpt from 131 Polymerizable warning [Flammable Liquids - Toxic]:

IMMEDIATE PRECAUTIONARY MEASURE: Isolate spill or leak area for at least 50 meters (150 feet) in all directions.

SPILL: Increase the immediate precautionary measure distance, in the downwind direction, as necessary.

FIRE: If tank, rail car or tank truck is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions. (ERG, 2020)
Firefighting
(Non-Specific -- Pesticide, Liquid, n.o.s.) Keep unnecessary people away; isolate hazard area and deny entry. Stay upwind; keep out of low areas. Ventilate closed spaces before entering them. Wear positive pressure breathing apparatus and special protective clothing. Remove and isolate contaminated clothing at the site. If water pollution occurs, notify appropriate authorities.

(Non-Specific -- Pesticide, Liquid, n.o.s.) Small fires: dry chemical, carbon dioxide, water spray, or foam. Large fires: water spray, fog, or foam. Move container from fire area if you can do so without risk. Fight fire from maximum distance. Dike fire control water for later disposal; do not scatter the material. (EPA, 1998)
Non-Fire Response
Avoid inhalation and skin contact. (Non-Specific -- Pesticide, Liquid, n.o.s.) Do not touch spilled material; stop leak if you can do so without risk. Use water spray to reduce vapors. For small spills, absorb with sand or other noncombustible absorbent material and place into containers for later disposal. For large spills, dike far ahead of spill for later disposal. (EPA, 1998)
Protective Clothing
For emergency situations, wear a positive pressure, pressure-demand, full facepiece self-contained breathing apparatus (SCBA) or pressure- demand supplied air respirator with escape SCBA and a fully-encapsulating, chemical resistant suit. (EPA, 1998)
DuPont Tychem® Suit Fabrics
No information available.
First Aid
Note: Methyl thiocyanate is very readily absorbed through the skin.

Signs and Symptoms of Methyl Thiocyanate Exposure: Signs and symptoms of acute exposure to methyl thiocyanate may include low blood pressure, apnea (cessation of breathing), nausea, vomiting, diarrhea, abdominal cramping, skin rashes, and exfoliative dermatitis. Muscle weakness, excitement, confusion, delirium, convulsions, and coma may be observed. Visual and auditory hallucinations as well as coryza (nasal inflammation and discharge), nystagmus (involuntary rapid eye movements), irritability, and anuria (absence of excretion of urine) may also occur.

Emergency Life-Support Procedures: Acute exposure to methyl thiocyanate may require decontamination and life support for the victims. Emergency personnel should wear protective clothing appropriate to the type and degree of contamination. Air-purifying or supplied-air respiratory equipment should also be worn, as necessary. Rescue vehicles should carry supplies such as plastic sheeting and disposable plastic bags to assist in preventing spread of contamination.

Inhalation Exposure:
1. Move victims to fresh air. Emergency personnel should avoid self-exposure to methyl thiocyanate.
2. 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 oxygen or other respiratory support.
3. Obtain authorization and/or further instructions from the local hospital for administration of an antidote or performance of other invasive procedures.
4. Rush to a health care facility.

Dermal/Eye Exposure:
1. Remove victims from exposure. Emergency personnel should avoid self-exposure to methyl thiocyanate.
2. 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 oxygen or other respiratory support.
3. Remove contaminated clothing as soon as possible.
4. If eye exposure has occurred, eyes must be flushed with lukewarm water for at least 15 minutes.
5. Wash exposed skin areas thoroughly with soap and water.
6. Obtain authorization and/or further instructions from the local hospital for administration of an antidote or performance of other invasive procedures.
7. Rush to a health care facility.

Ingestion Exposure:
1. 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 oxygen or other respiratory support.
2. Obtain authorization and/or further instruction from the local hospital for administration of an antidote or performance of other invasive procedures.
3. Vomiting may be induced with syrup of Ipecac. If elapsed time since ingestion of methyl thiocyanate is unknown or suspected to be greater than 30 minutes and show signs of seizures or coma, do not induce vomiting and proceed to Step
4. Ipecac should not be administered to children under 6 months of age. Warning: Ingestion of methyl thiocyanate 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 recommended dosages of Ipecac are: children up to 1 year old, 10 mL (1/3 oz); children 1 to 12 years old, 15 mL (1/2 oz); adults, 30 mL (1 oz). Ambulate (walk) the victims and give large quantities of water. If vomiting has not occurred after 15 minutes, Ipecac may be readministered. 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.
4. Activated charcoal may be administered if victims are conscious and alert. Use 15 to 30 g (1/2 to 1 oz) for children (1 to 2 g/kg in infants), 30 to 100 g (1 oz to 3-1/2 oz) in adults, with 125 to 250 ml (1/2 to 1 cup) of water.
5. 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; 30 to 100 g (1 oz to 3-1/2 oz) is recommended for adults.
6. Rush to a health care facility. (EPA, 1998)

Physical Properties

Chemical Formula:
  • C2H3NS
Flash Point: data unavailable
Lower Explosive Limit (LEL): data unavailable
Upper Explosive Limit (UEL): data unavailable
Autoignition Temperature: data unavailable
Melting Point: -60°F (EPA, 1998)
Vapor Pressure: 10 mmHg at 70.88°F (EPA, 1998)
Vapor Density (Relative to Air): data unavailable
Specific Gravity: 1.068 at 77°F (EPA, 1998) - Denser than water; will sink
Boiling Point: 266 to 271°F at 760 mmHg (EPA, 1998)
Molecular Weight: 73.12 (EPA, 1998)
Water Solubility: data unavailable
Ionization Energy/Potential: data unavailable
IDLH: data unavailable

AEGLs (Acute Exposure Guideline Levels)

No AEGL information available.

ERPGs (Emergency Response Planning Guidelines)

No ERPG information available.

PACs (Protective Action Criteria)

Chemical PAC-1 PAC-2 PAC-3
Methyl thiocyanate (556-64-9) 17 ppm 28 ppm 140 ppm
(DOE, 2018)

Regulatory Information

EPA Consolidated List of Lists

Regulatory Name CAS Number/
313 Category Code
EPCRA 302
EHS TPQ
EPCRA 304
EHS RQ
CERCLA RQ EPCRA 313
TRI
RCRA
Code
CAA 112(r)
RMP TQ
Methyl thiocyanate 556-64-9 10000 pounds 10000 pounds 20000 pounds
Thiocyanic acid, methyl ester 556-64-9 10000 pounds 10000 pounds 20000 pounds

(EPA List of Lists, 2022)

CISA Chemical Facility Anti-Terrorism Standards (CFATS)

RELEASE THEFT SABOTAGE
Chemical of Interest CAS Number Min Conc STQ Security
Issue
Min Conc STQ Security
Issue
Min Conc STQ Security
Issue
Methyl thiocyanate; [Thiocyanic acid, methyl ester] 556-64-9 1.00 % 20000 pounds toxic

(CISA, 2007)

OSHA Process Safety Management (PSM) Standard List

No regulatory information available.

Alternate Chemical Names