Methyl thiocyanate

H226 (98%): Flammable liquid and vapor [Warning Flammable liquids]

H301 (100%): Toxic if swallowed [Danger Acute toxicity, oral]

H311 (83.7%): Toxic in contact with skin [Danger Acute toxicity, dermal]

H315 (10.2%): Causes skin irritation [Warning Skin corrosion/irritation]

H319 (87.8%): Causes serious eye irritation [Warning Serious eye damage/eye irritation]

H330 (12.2%): Fatal if inhaled [Danger Acute toxicity, inhalation]

H331 (79.6%): Toxic if inhaled [Danger Acute toxicity, inhalation]

H335 (87.8%): May cause respiratory irritation [Warning Specific target organ toxicity, single exposure; Respiratory tract irritation]

P210, P233, P240, P241, P242, P243, P260, P261, P262, P264, P264+P265, P270, P271, P280, P284, P301+P316, P302+P352, P303+P361+P353, P304+P340, P305+P351+P338, P316, P319, P320, P321, P330, P332+P317, P337+P317, P361+P364, P362+P364, P370+P378, P403+P233, P403+P235, P405, and P501 (click each P-code to see the statement)

Aggregated GHS information provided per 49 reports by companies from 7 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.

Information may vary between notifications depending on impurities, additives, and other factors. The percentage value in parenthesis indicates the notified classification ratio from companies that provide hazard codes. Only hazard codes with percentage values above 10% are shown. For more detailed information, please visit ECHA C&L website.

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.

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)

(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)

Excerpt from ERG Guide 131 [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 tank car or highway tank 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, 2024)

SRP: At the time of review, criteria for land treatment or burial (sanitary landfill) disposal practices are subject to significant revision. Prior to implementing land disposal of waste residue (including waste sludge), consult with environmental regulatory agencies for guidance on acceptable disposal practices.

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)

The compound is currently at the Holding Status AEGLs which have been reviewed by the NAC/AEGL Committee and are on hold due to insufficient data to develop AEGL values.

AEGLs Status: Holding

0.18 [mg/m3]

2.0 [mg/m3]

12 [mg/m3]

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)

Methyl thiocyanate is a 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)

Colorless liquid with an odor of onions; [Merck Index] Colorless or pale yellow liquid; [MSDSonline]

COLORLESS LIQUID

ONION ODOR

266 to 271 °F at 760 mmHg (EPA, 1998)

130-133 °C

-60 °F (EPA, 1998)

VERY SLIGHTLY SOL IN WATER; MISCIBLE WITH ALC, ETHER

Soluble in carbon tetrachloride.

1.068 at 77 °F (EPA, 1998) - Denser than water; will sink

1.068 g/cu cm at 25 °C

1.068 @25 °C

10 mmHg at 70.88 °F (EPA, 1998)

12.1 [mmHg]

12.1 mm Hg at 25 °C

VOLATILE

When heated to decomposition it emits very toxic fumes of NOx and SOx.

INDEX OF REFRACTION: 1.4669 @ 25 °C/D

INDEX OF REFRACTION: 1.4697 @ 20 °C/D

Coriolis coupling

Schoenflies notation

Boiling point

Centrifugal distortion

Chemical bond

Electric dipole moment

Equilibrium structure

Heat of sublimation

Hindering potential

Internuclear distance

Molecular dipole moment

Molecular structure

Moment of inertia

Nuclear quadrupole coupling

Nuclear quadrupole moment

Nuclear quadrupole resonance spectroscopy

Optical coefficient

Point group

Quadrupole coupling

Refractive index

Rotation-vibration spectrum

Very slightly soluble in water [Merck].

Isocyanates and Isothiocyanates

Sulfides, Organic

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].

Organic nitriles decompose into cyanide ions both in vivo and in vitro. Consequently the primary mechanism of toxicity for organic nitriles is their production of toxic cyanide ions or hydrogen cyanide. Cyanide is an inhibitor of cytochrome c oxidase in the fourth complex of the electron transport chain (found in the membrane of the mitochondria of eukaryotic cells). It complexes with the ferric iron atom in this enzyme. The binding of cyanide to this cytochrome prevents transport of electrons from cytochrome c oxidase to oxygen. As a result, the electron transport chain is disrupted and the cell can no longer aerobically produce ATP for energy. Tissues that mainly depend on aerobic respiration, such as the central nervous system and the heart, are particularly affected. Cyanide is also known produce some of its toxic effects by binding to catalase, glutathione peroxidase, methemoglobin, hydroxocobalamin, phosphatase, tyrosinase, ascorbic acid oxidase, xanthine oxidase, succinic dehydrogenase, and Cu/Zn superoxide dismutase. Cyanide binds to the ferric ion of methemoglobin to form inactive cyanmethemoglobin. (L97)

No indication of carcinogenicity to humans (not listed by IARC).

Exposure to high levels of cyanide for a short time harms the brain and heart and can even cause coma, seizures, apnea, cardiac arrest and death. Chronic inhalation of cyanide causes breathing difficulties, chest pain, vomiting, blood changes, headaches, and enlargement of the thyroid gland. Skin contact with cyanide salts can irritate and produce sores. (L96, L97)

Oral (L96) ; inhalation (L96) ; dermal (L96)

Cyanide poisoning is identified by rapid, deep breathing and shortness of breath, general weakness, giddiness, headaches, vertigo, confusion, convulsions/seizures and eventually loss of consciousness. (L96, L97)

Other Poison - Chemical Asphyxiant

Dermatotoxin - Skin burns.

Lacrimator (Lachrymator) - A substance that irritates the eyes and induces the flow of tears.

Toxic Pneumonitis - Inflammation of the lungs induced by inhalation of metal fumes or toxic gases and vapors.

Antidotes to cyanide poisoning include hydroxocobalamin and sodium nitrite, which release the cyanide from the cytochrome system, and rhodanase, which is an enzyme occurring naturally in mammals that combines serum cyanide with thiosulfate, producing comparatively harmless thiocyanate. Oxygen therapy can also be administered. (L97)

For immediate first aid: Ensure that adequate decontamination has been carried out. If victim is not breathing, start artificial respiration, preferably with a demand-valve resuscitator, bag-valve-mask device, or pocket mask as trained. Perform CPR if necessary. Immediately flush contaminated eyes with gently flowing water. Do not induce vomiting. If vomiting occurs, lean patient forward or place on left side (head-down position, if possible) to maintain an open airway and prevent aspiration. Keep victim quiet and maintain normal body temperature. Obtain medical attention. /Isocyanates, aliphatic thiocyanates, and related compounds/

For basic treatment: Establish a patent airway. Suction if necessary. Watch for signs of respiratory insufficiency and assist ventilations if necessary. Administer oxygen by nonrebreather mask at 10 to 15 L/min. Monitor for pulmonary edema and treat if necessary ... Monitor for shock and treat if necessary ... Monitor for seizures and treat if necessary ... For eye contamination, flush eyes immediately with water. Irrigate each eye continuously with normal saline during transport ... Do not use emetics. For ingestion, rinse mouth and administer 5 mL/kg up to 200 mL of water for dilution if the patient can swallow, has a strong gag reflex, and does not drool. Administer activated charcoal ... . /Isocyanates, aliphatic thiocyanates, and related compounds/

Emergency medical transportation should be rapid. Preferred destination is a facility with a hyperbaric chamber if exposure to cyanide-producing/cyanide-releasing compounds. /Isocyanates, aliphatic thiocyanates, and related compounds/

SYMPTOMATOLOGY (LARGELY INFERRED FROM ANIMAL TESTS): 1. INGESTION OF CONCN SOLN MAY LEAD TO VOMITING BECAUSE OF MUCOSAL IRRITATION. ... 5. MASSIVE SKIN CONTAMINATION WITH ORGANIC THIOCYANATE SOLN MAY PRODUCE SYSTEMIC POISONING...&...LOCAL IRRITATION & DERMATITIS. /ALIPHATIC THIOCYANATES/

SYMPTOMATOLOGY (LARGELY INFERRED FROM ANIMAL TESTS): 6. IN NONFATAL CASES EVIDENCE OF INJURIES TO THE LIVER & KIDNEYS MAY APPEAR. /ALIPHATIC THIOCYANATES/

...METHYL.../THIOCYANATE IS/ RAPIDLY ACTING /POISON/...OF HIGH POTENCY...

THE SIGNS AND SYMPTOMS OF KEROSENE POISONING ARE OFTEN DOMINANT AFTER EXPOSURES TO DILUTE SOLN OF THIOCYANATE INSECTICIDES. /ALIPHATIC THIOCYANATES/

...PRODUCE CENTRAL NERVOUS DEPRESSION, USUALLY WITH A TRANSIENT PERIOD OF RESP STIMULATION, PROGRESSING PROMPTLY TO DEATH FROM RESP FAILURE. /ACUTE, RATS, ORAL/

METHYL THIOCYANATE SHOWED NO MUTAGENIC ACTIVITY WHEN TESTED ON SALMONELLA TYPHIMURIUM TA100 WITHOUT ACTIVATION WITH S-9 MIX.

METHYL THIOCYANATE ADDED AT 0.33% OF DIET FED TO LAYING HENS HAD NO EFFECT ON THYROID SIZE BUT REDUCED EGG IODINE & TENDED TO REDUCE FEED INTAKE.

THE LEVEL OF HYDROGEN CYANIDE IN MOUSE BRAIN & WHOLE HOUSEFLIES, RESULTING FROM TREATMENT WITH 16 VARIOUS ORGANOTHIOCYANATES & 6 ORGANONITRILES, CORRELATED WELL WITH THE TOXICITY OF THESE HYDROGEN CYANIDE PRECURSORS. P-AMINOPROPIOPHENONE PROTECTED MICE AGAINST LETHAL DOSES OF POTASSIUM CYANIDE, & OF MANY ORGANOTHIOCYANATES & ORGANONITRILES. THE REDUCED TOXICITY OF SEVERAL ORGANOTHIOCYANATES TO MICE, AFTER PRETREATMENT WITH FENITROTHION, PROBABLY RESULTED FROM A TEMPORARY REDUCTION IN THE GLUTATHIONE CONTENT OF THE LIVER.

Methyl thiocyanate's production and use as a chemical and pharmaceutical intermediate may result in its release to the environment. If released to the atmosphere, methyl thiocyanate is expected to exist solely in the vapor phase in the ambient atmosphere based upon a measured vapor pressure of 12 mm Hg at 25 °C. Vapor-phase methyl thiocyanate will be degraded by reaction with photochemically-produced hydroxyl radicals (estimated half-life 15 days). If released to soil, methyl thiocyanate is expected to have very high mobility based upon the estimated Koc of 8.3. Volatilization from moist and dry soil surfaces may occur given an estimated Henry's Law constant of 4.4X10-5 atm-cu m/mole and the measured vapor pressure, respectively. If released into water, methyl thiocyanate is not expected to adsorb to suspended solids and sediments in water based upon its estimated Koc. Methyl thiocyanate is expected to volatilize from water surfaces given its estimated Henry's Law constant. Estimated volatilization half-lives for a model river and model lake are 20 hours and 8.6 days, respectively. Bioconcentration of methyl thiocyanate in aquatic organisms is not expected to occur given an estimated BCF of 2.1. Methyl thiocyanate has been estimated to biodegrade fast, with primary biodegradation occurring over a period of weeks. Occupational exposure to methyl thiocyanate may occur through inhalation and dermal contact with this compound at workplaces where it is produced or used. (SRC)

Methyl thiocyanate is of anthropogenic origin, and is not known to be produced by natural sources. (SRC)

Methyl thiocyanate's production and use as a chemical and pharmaceutical intermediate(1) may result in its release to the environment(SRC).

TERRESTRIAL FATE: Based on a recommended classification scheme(1), an estimated Koc value of 8.3(SRC), determined from a structure estimation method(2), indicates that methyl thiocyanate is expected to have very high mobility in soil(SRC). Volatilization of methyl thiocyanate from moist soil surfaces is expected (SRC) based upon an estimated Henry's Law constant of 4.4X10-5 atm-cu m/mole(SRC), using a fragment constant estimation method(3). The potential for volatilization of methyl thiocyanate from dry soil surfaces is expected to exist(SRC) based on a measured vapor pressure of 12 mm Hg(4). Based upon a group contribution method for predicting the probability and rate of aerobic biodegradation(5), methyl thiocyanate has been estimated to biodegrade fast with primary biodegradation occurring over a period of days to weeks(SRC).

AQUATIC FATE: Based on a recommended classification scheme(1), an estimated Koc value of 8.3(SRC), determined from a structure estimation method(2), indicates that methyl thiocyanate is not expected to adsorb to suspended solids and sediment in water(SRC). Methyl thiocyanate is expected to volatilize from water surfaces(3,SRC) based on an estimated Henry's Law constant of 4.4X10-5 atm-cu m/mole(SRC), developed using a fragment constant estimation method(4). Estimated volatilization half-lives for a model river and model lake are 20 hours and 8.6 days, respectively(3,SRC). According to a classification scheme(5), an estimated BCF value of 2.1(3,SRC), from an estimated log Kow(6,SRC), suggests that bioconcentration in aquatic organisms is low(SRC). Based upon a group contribution method for predicting the probability and rate of aerobic biodegradation(7), methyl thiocyanate has been estimated to be highly biodegraded with ultimate biodegradation occurring over a period of weeks(SRC).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), methyl thiocyanate, which has an measured vapor pressure of 12 mm Hg at 25 °C(2,SRC), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase methyl thiocyanate is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals(SRC); the half-life for this reaction in air is estimated to be about 15 days(3,SRC).

Based upon a group contribution method for predicting the probability and rate of aerobic biodegradation(1), methyl thiocyanate has been estimated to biodegrade fast with primary biodegradation occurring over a period of days to weeks(SRC).

The rate constant for the vapor-phase reaction of methyl thiocyanate with photochemically-produced hydroxyl radicals has been estimated as 1.1X10-12 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1,SRC). This corresponds to an atmospheric half-life of about 15 days at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1,SRC). Methyl thiocyanate is not expected to undergo direct photolysis in the environment due to its lack of ability to absorb light in the environmental spectrum(SRC).

An estimated BCF value of 2.1 was calculated for methyl thiocyanate(SRC), using an estimated log Kow of 0.73(1,SRC) and a recommended regression-derived equation(2). According to a classification scheme(3), this BCF value suggests that bioconcentration in aquatic organisms is low(SRC).

Using a structure estimation method based on molecular connectivity indices(1), the Koc for methyl thiocyanate can be estimated to be about 8.3(SRC). According to a recommended classification scheme(2), this estimated Koc value suggests that methyl thiocyanate is expected to have very high mobility in soil(SRC).

The Henry's Law constant for methyl thiocyanate is estimated as 4.4X10-5 atm-cu m/mole(SRC) using a fragment constant estimation method(1). This value indicates that methyl thiocyanate will volatilize from water surfaces(2,SRC). Based on this Henry's Law constant, the volatilization half-life from a model river (1 m deep, flowing 1 m/sec, wind velocity of 3 m/sec) is estimated as approximately 20 hours(2,SRC). The volatilization half-life from a model lake (1 m deep, flowing 0.05 m/sec, wind velocity of 0.5 m/sec) is estimated as approximately 8.6 days(2,SRC). Methyl thiocyanate's Henry's Law constant(1,SRC) indicates that volatilization from moist soil surfaces is expected (SRC). The potential for volatilization of methyl thiocyanate from dry soil surfaces may exist(SRC) based on a measured vapor pressure of 12 mm Hg(4).

SEE ALIPHATIC THIOCYANATES. ALL DERIVATIVES HAVE AN APPRECIABLE PERCUTANEOUS TOXICITY, ALTHOUGH THIS IS NOT REGARDED AS AN IMPORTANT HAZARD WITH THE CONCN USUALLY EMPLOYED IN AGRICULTURE. /ALIPHATIC THIOCYANATES/

Occupational exposure to methyl thiocyanate may occur through inhalation and dermal contact with this compound at workplaces where it is produced or used. (SRC)

Methyl thiocyanate's production and use as a chemical and pharmaceutical intermediate may result in its release to the environment. If released to the atmosphere, methyl thiocyanate is expected to exist solely in the vapor phase in the ambient atmosphere based upon a measured vapor pressure of 12 mm Hg at 25 °C. Vapor-phase methyl thiocyanate will be degraded by reaction with photochemically-produced hydroxyl radicals (estimated half-life 15 days). If released to soil, methyl thiocyanate is expected to have very high mobility based upon the estimated Koc of 8.3. Volatilization from moist and dry soil surfaces may occur given an estimated Henry's Law constant of 4.4X10-5 atm-cu m/mole and the measured vapor pressure, respectively. If released into water, methyl thiocyanate is not expected to adsorb to suspended solids and sediments in water based upon its estimated Koc. Methyl thiocyanate is expected to volatilize from water surfaces given its estimated Henry's Law constant. Estimated volatilization half-lives for a model river and model lake are 20 hours and 8.6 days, respectively. Bioconcentration of methyl thiocyanate in aquatic organisms is not expected to occur given an estimated BCF of 2.1. Methyl thiocyanate has been estimated to biodegrade fast, with primary biodegradation occurring over a period of weeks. Occupational exposure to methyl thiocyanate may occur through inhalation and dermal contact with this compound at workplaces where it is produced or used. (SRC)

Methyl thiocyanate is of anthropogenic origin, and is not known to be produced by natural sources. (SRC)

Methyl thiocyanate's production and use as a chemical and pharmaceutical intermediate(1) may result in its release to the environment(SRC).

TERRESTRIAL FATE: Based on a recommended classification scheme(1), an estimated Koc value of 8.3(SRC), determined from a structure estimation method(2), indicates that methyl thiocyanate is expected to have very high mobility in soil(SRC). Volatilization of methyl thiocyanate from moist soil surfaces is expected (SRC) based upon an estimated Henry's Law constant of 4.4X10-5 atm-cu m/mole(SRC), using a fragment constant estimation method(3). The potential for volatilization of methyl thiocyanate from dry soil surfaces is expected to exist(SRC) based on a measured vapor pressure of 12 mm Hg(4). Based upon a group contribution method for predicting the probability and rate of aerobic biodegradation(5), methyl thiocyanate has been estimated to biodegrade fast with primary biodegradation occurring over a period of days to weeks(SRC).

AQUATIC FATE: Based on a recommended classification scheme(1), an estimated Koc value of 8.3(SRC), determined from a structure estimation method(2), indicates that methyl thiocyanate is not expected to adsorb to suspended solids and sediment in water(SRC). Methyl thiocyanate is expected to volatilize from water surfaces(3,SRC) based on an estimated Henry's Law constant of 4.4X10-5 atm-cu m/mole(SRC), developed using a fragment constant estimation method(4). Estimated volatilization half-lives for a model river and model lake are 20 hours and 8.6 days, respectively(3,SRC). According to a classification scheme(5), an estimated BCF value of 2.1(3,SRC), from an estimated log Kow(6,SRC), suggests that bioconcentration in aquatic organisms is low(SRC). Based upon a group contribution method for predicting the probability and rate of aerobic biodegradation(7), methyl thiocyanate has been estimated to be highly biodegraded with ultimate biodegradation occurring over a period of weeks(SRC).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), methyl thiocyanate, which has an measured vapor pressure of 12 mm Hg at 25 °C(2,SRC), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase methyl thiocyanate is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals(SRC); the half-life for this reaction in air is estimated to be about 15 days(3,SRC).

Based upon a group contribution method for predicting the probability and rate of aerobic biodegradation(1), methyl thiocyanate has been estimated to biodegrade fast with primary biodegradation occurring over a period of days to weeks(SRC).

The rate constant for the vapor-phase reaction of methyl thiocyanate with photochemically-produced hydroxyl radicals has been estimated as 1.1X10-12 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1,SRC). This corresponds to an atmospheric half-life of about 15 days at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1,SRC). Methyl thiocyanate is not expected to undergo direct photolysis in the environment due to its lack of ability to absorb light in the environmental spectrum(SRC).

An estimated BCF value of 2.1 was calculated for methyl thiocyanate(SRC), using an estimated log Kow of 0.73(1,SRC) and a recommended regression-derived equation(2). According to a classification scheme(3), this BCF value suggests that bioconcentration in aquatic organisms is low(SRC).

Using a structure estimation method based on molecular connectivity indices(1), the Koc for methyl thiocyanate can be estimated to be about 8.3(SRC). According to a recommended classification scheme(2), this estimated Koc value suggests that methyl thiocyanate is expected to have very high mobility in soil(SRC).

The Henry's Law constant for methyl thiocyanate is estimated as 4.4X10-5 atm-cu m/mole(SRC) using a fragment constant estimation method(1). This value indicates that methyl thiocyanate will volatilize from water surfaces(2,SRC). Based on this Henry's Law constant, the volatilization half-life from a model river (1 m deep, flowing 1 m/sec, wind velocity of 3 m/sec) is estimated as approximately 20 hours(2,SRC). The volatilization half-life from a model lake (1 m deep, flowing 0.05 m/sec, wind velocity of 0.5 m/sec) is estimated as approximately 8.6 days(2,SRC). Methyl thiocyanate's Henry's Law constant(1,SRC) indicates that volatilization from moist soil surfaces is expected (SRC). The potential for volatilization of methyl thiocyanate from dry soil surfaces may exist(SRC) based on a measured vapor pressure of 12 mm Hg(4).

SEE ALIPHATIC THIOCYANATES. ALL DERIVATIVES HAVE AN APPRECIABLE PERCUTANEOUS TOXICITY, ALTHOUGH THIS IS NOT REGARDED AS AN IMPORTANT HAZARD WITH THE CONCN USUALLY EMPLOYED IN AGRICULTURE. /ALIPHATIC THIOCYANATES/

Occupational exposure to methyl thiocyanate may occur through inhalation and dermal contact with this compound at workplaces where it is produced or used. (SRC)

SRP: At the time of review, criteria for land treatment or burial (sanitary landfill) disposal practices are subject to significant revision. Prior to implementing land disposal of waste residue (including waste sludge), consult with environmental regulatory agencies for guidance on acceptable disposal practices.

Poison Flammable Liquid