Methyl Isocyanate

H225: Highly Flammable liquid and vapor [Danger Flammable liquids]

H301: Toxic if swallowed [Danger Acute toxicity, oral]

H311: Toxic in contact with skin [Danger Acute toxicity, dermal]

H315: Causes skin irritation [Warning Skin corrosion/irritation]

H317: May cause an allergic skin reaction [Warning Sensitization, Skin]

H318: Causes serious eye damage [Danger Serious eye damage/eye irritation]

H330: Fatal if inhaled [Danger Acute toxicity, inhalation]

H334: May cause allergy or asthma symptoms or breathing difficulties if inhaled [Danger Sensitization, respiratory]

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

H361d ***: Suspected of damaging the unborn child [Warning Reproductive toxicity]

P203, P210, P233, P240, P241, P242, P243, P260, P261, P262, P264, P264+P265, P270, P271, P272, P280, P284, P301+P316, P302+P352, P303+P361+P353, P304+P340, P305+P354+P338, P316, P317, P318, P319, P320, P321, P330, P332+P317, P333+P317, P342+P316, P361+P364, P362+P364, P370+P378, P403, P403+P233, P403+P235, P405, and P501 (click each P-code to see the statement)

H225 (94.4%): Highly Flammable liquid and vapor [Danger Flammable liquids]

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

H311 (100%): Toxic in contact with skin [Danger Acute toxicity, dermal]

H315 (100%): Causes skin irritation [Warning Skin corrosion/irritation]

H317 (100%): May cause an allergic skin reaction [Warning Sensitization, Skin]

H318 (100%): Causes serious eye damage [Danger Serious eye damage/eye irritation]

H330 (100%): Fatal if inhaled [Danger Acute toxicity, inhalation]

H334 (100%): May cause allergy or asthma symptoms or breathing difficulties if inhaled [Danger Sensitization, respiratory]

H335 (94.4%): May cause respiratory irritation [Warning Specific target organ toxicity, single exposure; Respiratory tract irritation]

H361 (100%): Suspected of damaging fertility or the unborn child [Warning Reproductive toxicity]

Aggregated GHS information provided per 18 reports by companies from 4 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.

H341: Suspected of causing genetic defects [Warning Germ cell mutagenicity]

H360: May damage fertility or the unborn child [Danger Reproductive toxicity]

H370: Causes damage to organs [Danger Specific target organ toxicity, single exposure]

P203, P210, P233, P240, P241, P242, P243, P260, P261, P262, P264, P264+P265, P270, P271, P272, P280, P284, P301+P316, P302+P352, P303+P361+P353, P304+P340, P305+P354+P338, P308+P316, P316, P317, P318, P320, P321, P330, P332+P317, P333+P317, P342+P316, P361+P364, P362+P364, P370+P378, P403, P403+P233, P403+P235, P405, and P501 (click each P-code to see the statement)

H310: Fatal in contact with skin [Danger Acute toxicity, dermal]

H314: Causes severe skin burns and eye damage [Danger Skin corrosion/irritation]

H361d: Suspected of damaging the unborn child [Warning Reproductive toxicity]

H372: Causes damage to organs through prolonged or repeated exposure [Danger Specific target organ toxicity, repeated exposure]

P203, P210, P233, P240, P241, P242, P243, P260, P261, P262, P264, P270, P271, P272, P280, P284, P301+P316, P301+P330+P331, P302+P352, P302+P361+P354, P303+P361+P353, P304+P340, P305+P354+P338, P316, P318, P319, P320, P321, P330, P333+P317, P342+P316, P361+P364, P362+P364, P363, P370+P378, P403, P403+P233, P403+P235, P405, and P501 (click each P-code to see the statement)

Fresh air, rest. Half-upright position. Artificial respiration may be needed. Refer for medical attention.

Remove contaminated clothes. Rinse skin with plenty of water or shower. Refer for medical attention .

First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then refer for medical attention.

Rinse mouth. Do NOT induce vomiting. Give one or two glasses of water to drink. Refer for medical attention .

Warning: Effects may be delayed for up to 15 hours. Caution is advised.

Signs and Symptoms of Acute Methyl Isocyanate Exposure: Acute exposure to methyl isocyanate may result in respiratory tract irritation, cough, chest tightness and pain, dyspnea (shortness of breath), asthmatic episodes, and pulmonary edema. Contact with the skin, eyes, and mucous membranes may result in severe irritation and permanent damage.

Emergency Life-Support Procedures: Acute exposure to methyl isocyanate 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 isocyanate.

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. Transport to a health care facility.

Dermal/Eye Exposure:

1. Remove victims from exposure. Emergency personnel should avoid self- exposure to methyl isocyanate.

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 twice 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. Transport 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 instructions from the local hospital for administration of an antidote or performance of other invasive procedures.

3. Activated charcoal may be administered if victims are conscious and alert. Use 15 to 30 g (1/2 to 1 oz) for children, 50 to 100 g (1-3/4 to 3-1/2 oz) for adults, with 125 to 250 mL (1/2 to 1 cup) of water.

4. 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 100 g (1-3/4 to 3-1/2 oz) is recommended for adults.

5. Transport to a health care facility. (EPA, 1998)

General First Aid:

· Call 911 or emergency medical service.

· Ensure that medical personnel are aware of the material(s) involved, take precautions to protect themselves and avoid contamination.

· Move victim to fresh air if it can be done safely.

· Administer oxygen if breathing is difficult.

· If victim is not breathing:

-- DO NOT perform mouth-to-mouth resuscitation; the victim may have ingested or inhaled the substance.

-- If equipped and pulse detected, wash face and mouth, then give artificial respiration using a proper respiratory medical device (bag-valve mask, pocket mask equipped with a one-way valve or other device).

-- If no pulse detected or no respiratory medical device available, provide continuous compressions. Conduct a pulse check every two minutes or monitor for any signs of spontaneous respirations.

· Remove and isolate contaminated clothing and shoes.

· For minor skin contact, avoid spreading material on unaffected skin.

· In case of contact with substance, remove immediately by flushing skin or eyes with running water for at least 20 minutes.

· For severe burns, immediate medical attention is required.

· Effects of exposure (inhalation, ingestion, or skin contact) to substance may be delayed.

· Keep victim calm and warm.

Material is extremely hazardous to health but areas may be entered with extreme care. Full protective clothing, including self-contained breathing apparatus (coat, pants, gloves, boots, and bands around legs, arms and waist) should be provided. No skin surface should be exposed. Stay away from ends of tanks. Do not get water inside container. Spray cooling water on containers that are exposed to flames until well after fire is out. Withdraw immediately in case of rising sound from venting safety device or any discoloration of tank due to fire.

Small fires: dry chemical, carbon dioxide, water spray, or foam. Large fires: water spray, fog, or foam. (EPA, 1998)

Use alcohol-resistant foam, dry sand, powder, carbon dioxide. NO hydrous agents. In case of fire: keep drums, etc., cool by spraying with water. NO direct contact with water. Combat fire from a sheltered position.

Evacuation: If fire becomes uncontrollable or container is exposed to direct flame - consider evacuation of one-third (1/3) mile radius.

If material on fire or involved in fire: Do not extinguish the fire unless flow can be stopped. Use water in flooding quantities as fog. Solid streams of water may in ineffective. Cool all affected containers with flooding quantities of water. Apply water from as far a distance as possible. Use "alcohol" foam, dry chemical or carbon dioxide.

... Approach fire from upwind to avoid hazardous vapors and toxic decomposition products ...

Alcohol-resistant foam, dry sand, powder, carbon dioxide. NO hydrous agents ... Cool drums, etc., by spraying with water but avoid contact of the substance with water ...

A harmful contamination of the air can be reached very quickly on evaporation of this substance at 20 °C ... Reacts violently with fire extinguishing agents such as water and hydrated agents.

... Vapors are heavier than air and may travel to a source of ignition and flash vack. Closed containers may rupture violently when heated ... Reacts with water, which may cause runaway reaction ...

· CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper not available or no answer, refer to appropriate telephone number listed on the inside back cover.

· Keep unauthorized personnel away.

· Stay upwind, uphill and/or upstream.

· Ventilate closed spaces before entering, but only if properly trained and equipped.

· ELIMINATE all ignition sources (no smoking, flares, sparks or flames) from immediate area.

· All equipment used when handling the product must be grounded.

· Do not touch damaged containers or spilled material unless wearing appropriate protective clothing.

· Stop leak if you can do it without risk.

· A vapor-suppressing foam may be used to reduce vapors.

· FOR CHLOROSILANES, use alcohol-resistant foam to reduce vapors.

· DO NOT GET WATER on spilled substance or inside containers.

· Use water spray to reduce vapors or divert vapor cloud drift. Avoid allowing water runoff to contact spilled material.

· Prevent entry into waterways, sewers, basements or confined areas.

Small Spill

· Cover with DRY earth, DRY sand or other non-combustible material followed with plastic sheet to minimize spreading or contact with rain.

· Use clean, non-sparking tools to collect material and place it into loosely covered plastic containers for later disposal.

Excerpt from ERG Guide 155 [Substances - Toxic and/or Corrosive (Flammable / Water-Sensitive); polymerization hazard]:

IMMEDIATE PRECAUTIONARY MEASURE: Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters (75 feet) for solids.

SPILL: See ERG Table 1 - Initial Isolation and Protective Action Distances on the UN/NA 2480 datasheet.

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)

Immediate precautionary measure

· Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters (75 feet) for solids.

· For highlighted materials: see Table 1 - Initial Isolation and Protective Action Distances.

· For non-highlighted materials: increase the immediate precautionary measure distance, in the downwind direction, as necessary.

· 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.

Small spill:

- ISOLATE in all directions: 150 m (500 ft)

Large spill:

- ISOLATE in all directions: 1000 m (3000 ft)

- PROTECT people from downwind during DAY time: 1.7 km (1.1 mi)

- PROTECT people from downwind during NIGHT time: 5.2 km (3.3 mi)

- PROTECT people from downwind during DAY time: 11.0+ km (7.0+ mi)

- PROTECT people from downwind during NIGHT time: 11.0+ km (7.0+ mi)

Evacuate danger area! Consult an expert! Personal protection: chemical protection suit including self-contained breathing apparatus. Ventilation. Remove all ignition sources. Do NOT let this chemical enter the environment. Collect leaking and spilled liquid in sealable containers as far as possible. Cautiously neutralize spilled liquid with caustic soda. Absorb remaining liquid in dry sand or inert absorbent. Then store and dispose of according to local regulations.

Activated alumina is used as sorbent for hydrolytic removal of methyl isocyanate from waste gases.

Remove all ignition sources. Ventilate area of spill or leak. For small quantities, absorb on paper towels. Evaporate into safe place (such as fume hood). Allow sufficient time for evaporating vapors to completely clear the hood ductwork. Burn the paper in suitable location away from combustible materials. Large quantities can be reclaimed or collected and atomized in a suitable combustion chamber equipped with appropriate effluent gas cleaning device. Methyl isocyanate should not be allowed to enter a confined space, such as a sewer, because of the possibility of explosion.

Releases may require isolation or evacuation. Eliminate all ignition sources. Stop of control the leak, if this can be done without undue risk. Use water spray to cool and disperse vapors and protect personnel. Approach release from upwind. Absorb in non-combustible material for proper disposal.

Evacuate danger area! Consult an expert! Ventilation. Remove all ignition sources. Collect leaking liquid in sealable containers. Cautiously neutralize spilled liquid with caustic soda. Absorb remaining liquid in dry sand or inert absorbent and remove to safe place. Chemical protection suit including self-contained breathing apparatus. Do NOT let this chemical enter the environment.

Generators of waste (equal to or greater than 100 kg/mo) containing this contaminant, EPA hazardous waste number P064, must conform with USEPA regulations in storage, transportation, treatment and disposal of waste.

A good candidate for liquid injection incineration at a temperature range of 650 to 1,600 °C and a residence time of 0.1 to 2 seconds. A good candidate for rotary kiln incineration at a temperature range of 820 to 1,600 °C and residence times of seconds for liquids and gases, and hours for solids. A good candidate for fluidized bed incineration at a temperature range of 450 to 980 °C and residence times of seconds for liquids and gases, and longer for solids.

Excerpt from ERG Guide 155 [Substances - Toxic and/or Corrosive (Flammable / Water-Sensitive); polymerization hazard]:

ELIMINATE all ignition sources (no smoking, flares, sparks or flames) from immediate area. All equipment used when handling the product must be grounded. Do not touch damaged containers or spilled material unless wearing appropriate protective clothing. Stop leak if you can do it without risk. A vapor-suppressing foam may be used to reduce vapors. FOR CHLOROSILANES, use alcohol-resistant foam to reduce vapors. DO NOT GET WATER on spilled substance or inside containers. Use water spray to reduce vapors or divert vapor cloud drift. Avoid allowing water runoff to contact spilled material. Prevent entry into waterways, sewers, basements or confined areas.

SMALL SPILL: Cover with DRY earth, DRY sand or other non-combustible material followed with plastic sheet to minimize spreading or contact with rain. Use clean, non-sparking tools to collect material and place it into loosely covered plastic containers for later disposal. (ERG, 2024)

Fireproof. See Chemical Dangers. Cool. Dry. Store only if stabilized. Store in an area without drain or sewer access.

Fireproof ... Store only if stabilized.

Store in a cool, dry, well-ventilated location. Store away from heat, oxidizing materials, and sunlight. Separate from acids, bases, amines, oxidizing materials, water, iron, tin, and copper. Outside or detached storage is preferred.

· Wear positive pressure self-contained breathing apparatus (SCBA).

· Wear chemical protective clothing that is specifically recommended by the manufacturer when there is NO RISK OF FIRE.

· Structural firefighters' protective clothing provides thermal protection but only limited chemical protection.

TIH (Toxic Inhalation Hazard) - Term used to describe gases and volatile liquids that are toxic when inhaled. Some are TIH materials themselves, e.g., chlorine, and some release TIH gases when spilled in water, e.g., chlorosilanes. [ERG 2016].

0.01 [ppm]

AEGL 1: Notable discomfort, irritation, or certain asymptomatic non-sensory effects. However, the effects are not disabling and are transient and reversible upon cessation of exposure (Unit: ppm)

AEGL 2: Irreversible or other serious, long-lasting adverse health effects or an impaired ability to escape (Unit: ppm)

AEGL 3: Life-threatening health effects or death (Unit: ppm)

NR= Not recommended since AEGL-1 irritation levels would exceed AEGL-2

AEGLs Status: Final

0.025 [ppm]

0.067 [ppm]

0.20 [ppm]

0.02 ppm (0.05 mg/m³)

TWA 0.02 ppm (0.05 mg/m³) [skin]

0.02 [ppm]

0.12 ppm (NIOSH, 2024)

0.12 [ppm]

Excerpts from Documentation for IDLHs: Lacrimation and irritation of the eyes, mucous membranes and skin; Human data: Volunteers experienced eye irritation and lacrimation after 1 to 5 minutes at 2 ppm, with more marked irritation at 4 ppm; exposures were unbearable at 21 ppm [Kimmerle and Eben 1964]. In another study, volunteers noted eye irritation and lacrimation at 5 ppm in less than 50 seconds [Mellon 1963].

0.12 ppm

See: 2017-105

0.06 [ppm]

8 hr Time Weighted Avg (TWA): 0.02 ppm, skin.

Excursion Limit Recommendation: Excursions in worker exposure levels may exceed 3 times the TLV-TWA for no more than a total of 30 minutes during a work day, and under no circumstances should they exceed 5 times the TLV-TWA, provided that the TLV-TWA is not exceeded.

0.02 ppm as TWA; 0.06 ppm as STEL; (skin); (SEN).

0.02 ppm [2013]

0.06 ppm [2013]

0.02 ppm as STEL

0.024 mg/m

· Note: Most foams will react with the material and release corrosive/toxic gases.

CAUTION: For Acetyl chloride (UN1717), use CO2 or dry chemical only.

Small Fire

· CO2, dry chemical, dry sand, alcohol-resistant foam.

Large Fire

· Water spray, fog or alcohol-resistant foam.

· FOR CHLOROSILANES, DO NOT USE WATER; use alcohol-resistant foam.

· If it can be done safely, move undamaged containers away from the area around the fire.

· Avoid aiming straight or solid streams directly onto the product.

Fire Involving Tanks, Rail Tank Cars or Highway Tanks

· Fight fire from maximum distance or use unmanned master stream devices or monitor nozzles.

Methyl isocyanate appears as a colorless low-boiling liquid (b.p. 39 °C) that is denser than water. Flash point is less than 20 °F. Very toxic by inhalation. Can be absorbed through the skin. Has a sharp odor, but the sense of smell cannot be relied upon to warn of the presence of vapors at low concentrations. Rate of onset: Immediate Persistence: Minutes to hours Odor threshold: 2.1 ppm Source/use/other hazard: Intermediate in manufacturing; reacts with H20 (don't use in fire).

Colorless liquid with a sharp, pungent odor; [NIOSH]

VOLATILE COLOURLESS LIQUID WITH PUNGENT ODOUR.

Colorless liquid with a sharp, pungent odor.

Colorless liquid

Sharp, unpleasant odor

102 °F at 760 mmHg (EPA, 1998)

38.3 °C @760 [mm Hg]

102-104 °F

-112 °F (EPA, 1998)

19 °F (EPA, 1998)

19 °F (-7 °C) (Closed cup)

-7 °C c.c.

Decomposes (NTP, 1992)

10 G/100 ML WATER AT 15 °C

Solubility in water at 20 °C: reaction

(59 °F): 10%

0.9599 at 68 °F (EPA, 1998) - Less dense than water; will float

0.9230 g/cu cm at 27 °C

Isocyanates...are highly reactive and undergo addition reactions across the carbon-nitrogen double bond of the NCO group. Reactions with alcohols, carboxylic acids, and amines have been widely exploited...The basis for the high reactivity of the isocyanates is the low electron density of the central carbon...Electron withdrawing or donating substituents alter the electrophilic nature of the isocyanate... /Isocyanates/

Relative density (water = 1): 0.96

0.9588 @ 20°C

About twice as heavy as air (EPA, 1998) (Relative to Air)

1.42 (AIR= 1)

Relative vapor density (air = 1): 2

348 mmHg at 68 °F (EPA, 1998)

348.0 [mmHg]

348 mm Hg at 20 °C

Vapor pressure, kPa at 20 °C: 54

348 mmHg

750 [mm Hg] @38.799999999999997 °C

995 °F (USCG, 1999)

994 °F (534 °C)

The substance decomposes on contact with water. The substance decomposes rapidly on contact with acids and bases producing toxic gases (hydrogen cyanide, nitrogen oxides, carbon monoxide).

When heated to decomposition it emits toxic fumes of /nitrogen oxides and hydrogen cyanide/.

Methyl isocyanate diffuses through polyethylene and attacks most elastomers (fluorocarbon resins are resistant). It is dangerous to use materials other than stainless steel, nickel, or glass/ceramic in contact with methyl isocyanate. In particular, do not use iron, steel, zinc, tin, copper, or their alloys.

269.4 KCAL/G MOL WT (LIQ)

10.67 eV

The substance will polymerize when pure. The substance may polymerize due to heating and under the influence of metals and catalysts.

... May polymerize explosively ... Uninhibited monomer vapor may form polymer in vents and other confined spaces ...

Highly flammable. Reacts exothermically with water to produce carbon dioxide, methylamine, dimethylurea and/or trimethylbiuret. Heat of reaction causes evolution of the vapors of the isocyanate. Reaction is relatively slow below 20 °C but becomes violent at more elevated temperatures or in the presence of acids and bases.

Isocyanates and Isothiocyanates

Polymerizable Compounds

Highly Flammable

Polymerizable

Water-Reactive

Airborne vapors of METHYL ISOCYANATE are explosive when exposed to heat, flame or sparks. Vapor may ignite on contact with strong oxidizing agents. Emits toxic fumes of nitriles and oxides of nitrogen when heated to decomposition [Lewis, 3rd ed., 1993, p. 860]. Caused the death of thousands in 1984 in Bhopal, India when released accidentally as a vapor following an exothermic reaction caused by contamination with water [Chem. Eng. News, 1985, 63(6), p. 27]. Reacts rapidly with acids and bases (including amines). May polymerize in contact with iron, tin, copper and certain other catalysts such as triphenylarsenic oxide, triethyl phosphine and tributyltin oxide. Polymerizes at elevated temperatures. Attacks some plastics, rubbers, and coatings [NTP].

Reacts with water, which may cause runaway reaction ...

The underlying cause of the disastrous release of methyl isocyanate at Bhopal in December 1984 which caused over 2000 fatalities is not certain ... However, it seems probable that an exothermic reaction in one of the three 13 cu m methyl isocyanate storage vessels had raised the internal temp to above the boiling point (39 °C), and that the continuing exotherm was beyond the capabilities of the cooling system to prevent a further substantial increase in pressure, which was eventually relieved through the emergency alkali scrubber and flare stack system. Unfortunately the partially inoperative scrubbing system could not deal with the rapid vapor release, and the flare system failed to ignite, so that of the 35 tons of isocyanate in the tank, some 23 tons were released during the 2 hr the safety valve was open. The origin of the exothermic reaction was not clear at the time, but it was known that alkyl isocyanates would trimerize to trialkyl isocyanurates in the presence of various catalysts, would react with amines to form alkylureas, and were hydrolyzed by water in presence of catalytic amt of acids or bases, with evolution of carbon dioxide. Contamination of the storage bessel(s) by moisture, methylamine or acidic or metallic impurities (possibly introduced via the nitrogen inerting system) may be the most likely underlying cause(s) of the disaster. The key role of water has now been confirmed. The Union Carbide report on the probable causes and course of the Bhopal disaster has been summarized. Analysis of the residue in the ruptured tank led to proposal of a mechanism, involving both water and chloroform as contaminants, to account for the detailed composition of the residue. A detailed analysis of the many factors and failings which led to the ingress of water into the storage rank and to the subsequent disastrous large-scale vapor release has been presented. The probable number of fatalities is given as between 5 and 8 thousand.

Attacks some forms of plastic, rubber and coatings.

... Contact with water causes formation of carbon dioxide and methylamine gases. The reaction is much more rapid in the presence of acids, alkalies, and amines.

Contact with iron, tin, copper (or salts of these elements) and with certain other catalysts (such as triphenylarsenic oxide, triethylphosphine, and tributyltin oxide) may cause violent polymerization and produce hazardous decomposition products: toxic gases and vapors (such as hydrogen cyanide, oxides of nitrogen, and carbon monoxide) may be released in a fire involving methyl isocyanate.

Water, oxidizers, acids, alkalis, amines, iron, tin, copper [Note: Usually contains inhibitors to prevent polymerization.]

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)

Methyl isocyanate

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)

The substance can be absorbed into the body by inhalation, through the skin and by ingestion.

inhalation, skin absorption, ingestion, skin and/or eye contact

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

Cough. Laboured breathing. Shortness of breath. Sore throat. Vomiting.

MAY BE ABSORBED! Redness. Pain. Burning sensation.

Pain. Redness. Loss of vision.

Abdominal pain. Burning sensation. Shock or collapse.

irritation eyes, skin, nose, throat; resp sensitization, cough, pulmonary secretions, chest pain, dyspnea (breathing difficulty); asthma; eye, skin damage; In Animals: pulmonary edema

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)

Eyes, skin, respiratory system

Reproductive Toxin - A chemical that is toxic to the reproductive system, including defects in the progeny and injury to male or female reproductive function. Reproductive toxicity includes developmental effects. See Guidelines for Reproductive Toxicity Risk Assessment.

Dermatotoxin - Skin burns.

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

Skin Sensitizer - An agent that can induce an allergic reaction in the skin.

Asthma - Reversible bronchoconstriction (narrowing of bronchioles) initiated by the inhalation of irritating or allergenic agents.

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

Fibrogenic - Inducing tissue injury and fibrosis (scarring).

LC50 (rat) = 6.1 ppm/6 hr

LD50: 213 mg/kg (Dermal, Rabbit) (T13)

LD50: 51.5 mg/kg (Oral, Rat) (T13)

LD50: 81.9 mg/kg (Subcutaneous, Mouse) (T13)

LC50: 12 200 ppb over 6 hours (Inhalation, Mouse) (T13)

LD50 Rat oral 140 mg/kg (95% confidence limit 55-340 mg/kg)

LD50 Mouse oral 120 mg/kg (95% confidence limit 78-200 mg/kg)

LD50 Rabbit percutaneous 1,800 mg/kg (95% confidence limit 950-3,410 mg/kg)

LD50 Rabbit dermal 213 mg/kg

For more Non-Human Toxicity Values (Complete) data for METHYL ISOCYANATE (13 total), please visit the HSDB record page.

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)

... Male Swiss Webster mice were exposed to methyl isocyanate vapor ... by whole body exposure for 3 hours at 40 ppm with and without prior food deprivation for 24 or 48 hours. Dexamethasone, atropine, ethanol, and sodium thiosulfate were administered by ip injection either 3 hours before or 1 hour after MIC treatment. Mice were sacrificed at the end of either 2 or 3 week observation periods. Methyl isocyanate exposure induced immediate nasal irritation and lacrimation and produced listlessness following initial brisk activity. Significant protection against the lethal effects of methyl isocyanate vapor was afforded by administration of dexamethasone prior to methyl isocyanate exposure and 24 hour prestarvation. The percent surviving 8 days after methyl isocyanate exposure were 56, 100, and 90 for the untreated, dexamethasone pretreated, and 24 hours prestarved groups. The percent surviving at post treatment day 21 was 10, 50, and 20 for the same respective treatment groups. Sodium thiosulfate provided some protection against methyl isocyanate poisoning with 50% of the treated animals surviving to day eight and 30% to day 21. The other treatment groups had survival rates comparable to the untreated animals.

Most treatment is symptomatic. Mydriatics, systemic analgesics, and topical antibiotics ... /such as sulfacetamide/ may be used for corneal abrasions. There is no effective therapy for sensitized workers, and these people should be moved to a work site devoid of exposure to isocynates. /Isocyanates/

Basic treatment: Establish a patent airway (oropharyngeal or nasopharyngeal airway, if needed). 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 0.9% saline (NS) 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 patent can swallow, has a strong gag reflex, and does not drool. Administer activated charcoal ... . /Isocyanates, aliphatic thiocyanates, and related compounds/

Advanced treatment: Consider orotracheal or nasotracheal intubation for airway control in the patient who is unconscious, has severe pulmonary edema, or is in severe respiratory distress. Positive-pressure ventilation techniques with a bag valve mask device may be beneficial. Consider drug therapy for pulmonary edema ... . Consider administering a beta agonist such as albuterol for severe bronchospasm ... . Monitor cardiac rhythm and treat arrhythmias if necessary ... . Start IV administration of D5W /SRP: "To keep open", minimal flow rate/. Use 0.9% saline (NS) or lactated Ringer's (LR) if signs of hypovolemia are present. For hypotension with signs of hypovolemia, administer fluid cautiously. Consider vasopressors if patient is hypotensive with a normal fluid volume. Watch for signs of fluid overload ... . Treat seizures with diazepam or lorazepam ... DIRECT PHYSICIAN ORDER ONLY ... . Use proparacaine hydrochloride to assist eye irrigation ... . /Isocyanates, aliphatic thiocyanates, and related compounds/

FIRST AID: Inhalation--Fresh air, rest. Half-upright position. Artificial respiration may be needed. Refer for medical attention ... The symptoms of lung oedema /and asthmas/ often do not become manifest until a few hours have passed and they are aggravated by physical effort. Rest and medical observation are therefore essential ... Skin--Remove contaminated clothes. Rinse skin with plenty of water or shower. Refer for medical attention; Eyes--First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then take to a doctor; Ingestion--Rinse mouth. Do NOT induce vomiting. Give plenty of water to drink. Refer for medical attention.

/HUMAN EXPOSURE STUDIES/ Acute experiments of 1- to 5-minute duration were performed on four human volunteers. At 0.4 ppm, volunteers could not perceive odor and experienced no irritation of the eyes, nose, or throat. At 2 ppm, no odor was detected, but the subjects experienced irritation and lacrimation. At 4 ppm, the symptoms of irritation were more marked. Exposure was unbearable at 21 ppm.[American Conference of Governmental Industrial Hygienists. Documentation of the TLV's and BEI's with Other World Wide Occupational Exposure Values. CD-ROM Cincinnati, OH 45240-1634 2005., p. 2]

/HUMAN EXPOSURE STUDIES/ When seven male volunteers were exposed to various concentrations of MIC, usually for 1 minute at 0, 0.3, 1.0, 2.5, or 5.0 ppm, only three of the seven subjects could detect 5 ppm MIC by its odor. There was no consistent relationship between odor detection and vapor concentration. All persons who perceived an odor reported olfactory fatigue. The only unanimous responses consisted of ocular irritation and lacrimation at 5 ppm in 50 seconds or less. All responses disappeared within 3 minutes after exposure.[American Conference of Governmental Industrial Hygienists. Documentation of the TLV's and BEI's with Other World Wide Occupational Exposure Values. CD-ROM Cincinnati, OH 45240-1634 2005., p. 2]

/HUMAN EXPOSURE STUDIES/ Of 113 methyl isocyanate (MIC)-exposed subjects studied initially at Bhopal, India, 79, 56, 68, and 87 were followed with clinical, lung function, radiographic, and immunologic tests at 3, 6, 12, 18, and 24 months. Though our cohort consisted of subjects at all ages showing a varied severity of initial illness, fewer females and young subjects were seen. Initially all had eye problems, but dominant symptoms were exertional dyspnea, cough, chest pain, sputum, and muscle weakness. A large number showed persistent depression mixed with anxiety, with disturbances of personality parameters. The early radiographic changes were lung edema, overinflation, enlarged heart, pleural scars, and consolidation. The persistent changes seen were interstitial deposits. Lung functions showed mainly restrictive changes with small airway obstruction; there was impairment of oxygen exchange. Oxygen exchange improved at 3-6 months, and spirometry improved at 12 months, only to decline later. The expiratory flow rates pertaining to large and medium airway function improved, but those for small airways remained low. There were changes of alveolitis in bronchoalveolar lavage fluid on fiber optic bronchoscopy, and in 11 cases positive MIC-specific antibodies to IgM, IgG, and IgE were demonstrated. On follow up, only 48% of the subjects were clinically stable, while 50% showed fluctuations. Thirty-two percent of the subjects had lung function fluctuations. Detailed sequential behavior over 2-4 years was predicted for dyspnea, forced vital capacity, maximum expiratory flow rate (0.25-0.75), peak expiratory flow rate, VO2, and depression score. A model for clinical behavior explained a total variance of 52.4% by using the factors of cough, PCO2 and X-ray zones in addition to above five parameters. The behavior of the railway colony group (1640 patients) revealed a similar pattern of illness. When this observed pattern of changes was transferred to the affected Bhopal city sections (with an equitable age-sex distribution), our model results were again validated. Thus the picture of MIC-induced disease seems similar despite the differences for age-sex and initial severity of illness in our cohort and in the population of Bhopal city as predicted by our model.[Kamat SR et al; Environ health Perspect 97: 241-53 (1992)]

/SIGNS AND SYMPTOMS/ Severe health hazard. May be fatal if absorbed through skin or inhaled. Irritating to skin, eyes, and respiratory system. Causes severe tearing. Symptoms of overexposure include coughing, mucous secretions, chest pain, dyspnea, asthma, eye and skin injury.[Fire Protection Guide to Hazardous Materials. 13 ed. Quincy, MA: National Fire Protection Association, 2002., p. 49-101]

For more Human Toxicity Excerpts (Complete) data for METHYL ISOCYANATE (35 total), please visit the HSDB record page.

/LABORATORY ANIMALS: Acute Exposure/ Upon topical application to intact, shaved rabbit skin, the undiluted material ... hemorrhage and marked edema of the skin at the site of application resulted from these covered doses. In an interdermal sensitization test, 16 of 16 guinea pigs had definite immunologic reactions that were obvious at 24 to 48 hours after receiving the challenge injection of 0.01 mL of a 0.01% solution.

4.60e+00

1.90e+01

1.00e+00

4.40e+00

2.10e+00

4.00e+01

5.90e-04

1.00e-03

Volatile

1.01e+04

1.40e+01

5.80e+01

3.10e+00

1.30e+01

6.30e+00

This substance may be hazardous to the environment. Special attention should be given to aquatic organisms.

Methyl isocyanate's production and use as a chemical intermediate and in the manufacture of carbamate-based and urea-based insecticides and fungicides may result in its release to the environment through various waste streams. If released to air, a vapor pressure of 348 mm Hg at 20 °C indicates methyl isocyanate will exist solely as a vapor in the atmosphere. Vapor-phase methyl isocyanate will be degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals; the half-life for this reaction in air is estimated to be 118 days. Methyl isocyanate does not contain chromophores that absorb at wavelengths >290 nm and therefore is not expected to be susceptible to direct photolysis by sunlight. Hydrolysis is expected to be the dominant fate process for methyl isocyanate in soil and water based upon half-lives of 20 and 9 min at 15 and 25 °C, respectively, calculated from measured aqueous hydrolysis rate constants. If released to soil, adsorption, biodegradation, and volatilization from moist soil surfaces are not expected to compete with hydrolysis as important fate processes; however, methyl isocyanate may volatilize from dry soil surfaces based upon its vapor pressure. If released to water, adsorption to sediment, bioconcentration, biodegradation, and volatilization from water surfaces are not expected to compete with hydrolysis as important fate processes. The products of hydrolysis may include N-carboxymethylamine, methylamine, carbon dioxide, and N,N'-dimethylurea. Occupational exposure to methyl isocyanate may occur through inhalation and dermal contact with this compound at workplaces where methyl isocyanate is produced or used. The general population may be exposed to methyl isocyanate through inhalation of cigarette smoke. (SRC)

Methyl isocyanate's production and use as a chemical intermediate and in the manufacture of carbamate-based and urea-based insecticides and fungicides(1-3) may result in its release to the environment through various waste streams(SRC).

Tobacco smoke from some brands of cigarettes also contains MIC (about 4 ug per cigarette).

TERRESTRIAL FATE: If methyl isocyanate is released to soil, it is expected to hydrolyze rapidly based on aqueous hydrolysis half-lives of 20 min at 15 °C and 9 min at 25 °C, calculated from measured rate constants of 5.9X10-4 sec-1 and 1.34X10-3 sec-1, respectively(1). Soil adsorption effects, volatilization, and biodegradation are not expected to be competing processes since hydrolysis proceeds so quickly. Methyl isocyanate is expected to volatilize from dry soil surfaces(SRC) based upon a vapor pressure of 348 mm Hg(2).

AQUATIC FATE: If methyl isocyanate is released to water, it is expected to hydrolyze rapidly based on half-lives of 20 min at 15 °C and 9 min at 25 °C, calculated from measured hydrolysis rate constants of 5.9X10-4 sec-1 and 1.34X10-3 sec-1, respectively(1). The products of hydrolysis may include N-carboxymethylamine, methylamine, carbon dioxide, and N,N'-dimethylurea(1,2). Bioconcentration, volatilization, adsorption to sediment and suspended solids, and biodegradation are not expected to be important fate processes(SRC) since hydrolysis proceeds so quickly.

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), methyl isocyanate, which has a vapor pressure of 348 mm Hg at 20 °C(2), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase methyl isocyanate 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 118 days(SRC), calculated from its rate constant of 1.4X10-13 cu cm/molecule-sec at 25 °C(SRC), that was derived using a structure estimation method(3). Methyl isocyanate does not contain chromophores that absorb at wavelengths >290 nm and therefore is not expected to be susceptible to direct photolysis by sunlight(4).

Since methyl isocyanate hydrolyzes rapidly in water(1), biodegradation is not expected to be an important fate process(SRC).

The rate constant for the vapor-phase reaction of methyl isocyanate with photochemically-produced hydroxyl radicals has been estimated as 1.4X10-13 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 118 days at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). Methyl isocyanate does not contain chromophores that absorb at wavelengths >290 nm and therefore is not expected to be susceptible to direct photolysis by sunlight(2). The measured overall rate constants for hydrolysis of methyl isocyanate in aqueous solution at 15 and 25 °C are 5.9X10-4 sec-1 and 1.34X10-3 sec-1, respectively(3). These correspond to half-lives of 20 and 9 min, respectively(1,SRC). The hydrolysis was found to be acid catalyzed(2) which suggests that hydrolysis may be faster in acidic solutions(SRC). The products of hydrolysis may include N-carboxymethylamine, methylamine, carbon dioxide, and N,N'-dimethylurea(3,4).

Since methyl isocyanate hydrolyzes rapidly in water(1), bioconcentration in aquatic organisms is not expected to be an important process(SRC).

Since methyl isocyanate hydrolyzes rapidly in water(1), adsorption to soil, sediment, and suspended solids are not expected to be an important process(SRC).

Since methyl isocyanate hydrolyzes rapidly in water(1), volatilization from moist soil or water surfaces is not expected to be an important process(SRC). Methyl isocyanate is expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 348 mm Hg at 20 °C(2).

Methyl isocyanate has been found in the smoke from several types of cigarettes at 1-5 ppm(1).

NIOSH (NOES Survey 1981-1983) has statistically estimated that 1,822 workers (272 of these are female) are potentially exposed to methyl isocyanate in the US(1). Occupational exposure to methyl isocyanate may occur through inhalation and dermal contact with this compound at workplaces where methyl isocyanate is produced or used(SRC). The general population may be exposed to methyl isocyanate through inhalation of cigarette smoke(SRC). The concentration of methyl isocyanate measured in a single air sample collected during a welding operation in a car repair shop was 290 ug/cu m(2).

A smoker receives an estimated dose of 4 ug/cigarette(1).

Generators of waste (equal to or greater than 100 kg/mo) containing this contaminant, EPA hazardous waste number P064, must conform with USEPA regulations in storage, transportation, treatment and disposal of waste.

A good candidate for liquid injection incineration at a temperature range of 650 to 1,600 °C and a residence time of 0.1 to 2 seconds. A good candidate for rotary kiln incineration at a temperature range of 820 to 1,600 °C and residence times of seconds for liquids and gases, and hours for solids. A good candidate for fluidized bed incineration at a temperature range of 450 to 980 °C and residence times of seconds for liquids and gases, and longer for solids.

Methyl isocyanate may be disposed of by atomizing in a suitable combustion chamber equipped with an appropriate effluent gas cleaning device.

Incineration: Spray into the furnace. Incineration will become easier by mixing with a more flammable solvent.

If ... THERE IS NO FIRE, go directly to the Table of Initial Isolation and Protective Action Distances /(see table below)/ ... to obtain initial isolation and protective action distances. IF THERE IS A FIRE, or IF A FIRE IS INVOLVED, go directly to the appropriate guide /(see guide(s) below)/ and use the evacuation information shown under PUBLIC SAFETY.

Table: Table of Initial Isolation and Protective Action Distances for Methyl isocyanate [Table#2913]

/GUIDE 155: SUBSTANCES - TOXIC and/or CORROSIVE (Flammable/Water-Sensitive)/ Fire or Explosion: HIGHLY FLAMMABLE: Will be easily ignited by heat, sparks or flames. Vapors form explosive mixtures with air: indoors, outdoors and sewers explosion hazards. Most vapors are heavier than air. They will spread along ground and collect in low or confined areas (sewers, basements, tanks). Vapors may travel to source of ignition and flash back. Those substances designated with a (P) may polymerize explosively when heated or involved in a fire. Substance will react with water (some violently) releasing flammable, toxic or corrosive gases and runoff. Contact with metals may evolve flammable hydrogen gas. Containers may explode when heated or if contaminated with water.

/GUIDE 155: SUBSTANCES - TOXIC and/or CORROSIVE (Flammable/Water-Sensitive)/ Health: TOXIC; inhalation, ingestion or contact (skin, eyes) with vapors, dusts or substance may cause severe injury, burns or death. Bromoacetates and chloroacetates are extremely irritating/lachrymators. Reaction with water or moist air will release toxic, corrosive or flammable gases. Reaction with water may generate much heat that will increase the concentration of fumes in the air. Fire will produce irritating, corrosive and/or toxic gases. Runoff from fire control or dilution water may be corrosive and/or toxic and cause pollution.

/GUIDE 155: SUBSTANCES - TOXIC and/or CORROSIVE (Flammable/Water-Sensitive)/ Public Safety: CALL Emergency Response Telephone Number on Shipping Paper first. If Shipping Paper not available or no answer, refer to appropriate telephone number listed on the inside back cover. As an immediate precautionary measure, isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters (75 feet) for solids. Keep unauthorized personnel away. Stay upwind. Keep out of low areas. Ventilate enclosed areas.

For more DOT Emergency Guidelines (Complete) data for METHYL ISOCYANATE (9 total), please visit the HSDB record page.

2480 155P

UN 2480; Methyl isocyanate

IMO 6.1; Methyl isocyanate

No person may /transport,/ offer or accept a hazardous material for transportation in commerce unless that person is registered in conformance ... and the hazardous material is properly classed, described, packaged, marked, labeled, and in condition for shipment as required or authorized by ... /the hazardous materials regulations (49 CFR 171-177)./

The International Air Transport Association (IATA) Dangerous Goods Regulations are published by the IATA Dangerous Goods Board pursuant to IATA Resolutions 618 and 619 and constitute a manual of industry carrier regulations to be followed by all IATA Member airlines when transporting hazardous materials.

The International Maritime Dangerous Goods Code lays down basic principles for transporting hazardous chemicals. Detailed recommendations for individual substances and a number of recommendations for good practice are included in the classes dealing with such substances. A general index of technical names has also been compiled. This index should always be consulted when attempting to locate the appropriate procedures to be used when shipping any substance or article.

Poison Inhalation Hazard Flammable Liquid

Special material.

Symbol: F+, T+; R: 12-24/25-26-37/38-41-42/43-63; S: (1/2)-26-27/28-36/37/39-45-63

UN Hazard Class: 6.1; UN Subsidiary Risks: 3; UN Pack Group: I