Carbon Monoxide

1Identification

Name

Carbon Monoxide

IUPAC name

carbon monoxide

CAS number

630-08-0

EC number

211-128-3

Molecular formula

CO

Molecular weight

28.01 g/mol

InChIKey

UGFAIRIUMAVXCW-UHFFFAOYSA-N

SMILES

[C-]#[O+]

PubChem CID

281

Synonyms

carbon monoxide, carbon monooxide, Carbonic oxide, Carbon oxide (CO), carbon(II) oxide, Exhaust gas, Flue gas, monoxide, Kohlenmonoxid, Koolmonoxyde, Kohlenoxyd, Wegla tlenek, Oxyde de carbone, Carbone (oxyde de)

Recommended uses

• An incomplete combustion product of carbon-containing materials and an emission of internal combustion engines; [ACGIH] Sewer construction workers can be poisoned by carbon monoxide migrating through the soil from nearby use of explosives. [Appl Occup Environ Hyg 2002 Mar;17(3):152-3]
  Haz-Map, Information on Hazardous Chemicals and Occupational Diseases
• Aluminum Producing [Category: Industry] Steel Producing [Category: Industry] Forging [Category: Heat or Machine] Molding and Core Making [Category: Foundry] Metal Preparation and Pouring [Category: Foundry] Shakeout, Cleaning, and Finishing [Category: Foundry] Welding [Category: Weld] Heat Treating [Category: Heat or Machine] Smelting Copper or Lead [Category: Industry] Gas Welding and Cutting [Category: Weld] Mining [Category: Industry] Sewer and Wastewater Treatment [Category: Industry] Firefighting [Category: Other] Cement Producing [Category: Industry] Burning Natural Polymers [Category: Burn] Welding Over Coatings [Category: Weld] Burning Synthetic Polymers [Category: Burn] Burning Cell…
  Haz-Map, Information on Hazardous Chemicals and Occupational Diseases
• Ceramics making [Category: Hobbies] Lost-wax casting [Category: Hobbies] Sculpturing plastics [Category: Hobbies] Glassblowing [Category: Hobbies] Smoking cigarettes [Category: Food & Drugs] Burning biomass fuel for cooking and heating [Category: Environments]
  Haz-Map, Information on Hazardous Chemicals and Occupational Diseases
• Processing aids not otherwise specified Other Intermediate Oxidizing agent Plasticizer Soil amendments (fertilizers)
  EPA Chemical Data Reporting (CDR)
• Processing aids not otherwise specified Intermediate Not Known or Reasonably Ascertainable
  EPA Chemical Data Reporting (CDR)

Description

• Carbon monoxide is a colorless, nonirritating, odorless, and tasteless gas. It is found in both outdoor and indoor air.
  Agency for Toxic Substances and Disease Registry (ATSDR)
• Carbon Monoxide can cause developmental toxicity according to an independent committee of scientific and health experts.
  California Office of Environmental Health Hazard Assessment (OEHHA)
• Carbon monoxide is a colorless, odorless gas. Prolonged exposure to carbon monoxide rich atmospheres may be fatal. It is easily ignited. It is just lighter than air and a flame can flash back to the source of leak very easily. Under prolonged exposure to fire or intense heat the containers may violently rupture and rocket.
  CAMEO Chemicals

2Hazard identification

Signal word

Danger

Pictograms

GHS02, GHS04, GHS06, GHS08

Classification source

Regulation (EC) No 1272/2008 of the European Parliament and of the Council

Precautionary statements

Other reported classifications

6 classification records exist across sources. Differences usually reflect purity, physical form or impurities.

NFPA 704 rating

• 3 - Materials that, under emergency conditions, can cause serious or permanent injury.
  Hazardous Substances Data Bank (HSDB)
• 4 - Materials that rapidly or completely vaporize at atmospheric pressure and normal ambient temperature or that are readily dispersed in air and burn readily.
  Hazardous Substances Data Bank (HSDB)
• 0 - Materials that in themselves are normally stable, even under fire conditions.
  Hazardous Substances Data Bank (HSDB)

Health hazards

• Inhalation causes headache, dizziness, weakness of limbs, confusion, nausea, unconsciousness, and finally death. 0.04% conc., 2-3 hr. or 0.06% conc., 1 hr.- headache and discomfort; with moderate exercise, 0.1-0.2% will produce throbbing in the head in about 1/2 hr., a tendency to stagger in about 1 1/2 hr., and confusion of the mind, headache, and nausea in about 2 hrs. 0.20-25% usually produces unconsciousness in about 1/2 hr. Inhalation of a 0.4% conc. can prove fatal in less than 1 hr. Inhalation of high concentrations can cause sudden, unexpected collapse. Contact of liquid with skin will cause frostbite. (USCG, 1999)
  CAMEO Chemicals
• Excerpt from ERG Guide 168 [Carbon Monoxide (Refrigerated Liquid)]: TOXIC; Extremely Hazardous. Inhalation extremely dangerous; may be fatal. Contact with gas, liquefied gas or cryogenic liquids may cause burns, severe injury and/or frostbite. Odorless, will not be detected by sense of smell. (ERG, 2024)
  CAMEO Chemicals
• · TOXIC; Extremely Hazardous. · Inhalation extremely dangerous; may be fatal. · Contact with gas, liquefied gas or cryogenic liquids may cause burns, severe injury and/or frostbite. · Odorless, will not be detected by sense of smell.
  Emergency Response Guidebook (ERG)

Fire hazards

• Special Hazards of Combustion Products: Asphyxiation due to carbon dioxide production may result. Behavior in Fire: Flame has very little color. Containers may explode in fire. (USCG, 1999)
  CAMEO Chemicals
• Excerpt from ERG Guide 168 [Carbon Monoxide (Refrigerated Liquid)]: EXTREMELY FLAMMABLE. CAUTION: Flame can be invisible. Use an alternate method of detection (thermal camera, broom handle, etc.) May be ignited by heat, sparks or flames. Containers may explode when heated. Vapor explosion and poison hazard indoors, outdoors or in sewers. Vapors from liquefied gas are initially heavier than air and spread along ground. Vapors may travel to source of ignition and flash back. Runoff may create fire or explosion hazard. (ERG, 2024)
  CAMEO Chemicals
• · EXTREMELY FLAMMABLE. CAUTION: Flame can be invisible. Use an alternate method of detection (thermal camera, broom handle, etc.) · May be ignited by heat, sparks or flames. · Containers may explode when heated. · Vapor explosion and poison hazard indoors, outdoors or in sewers. · Vapors from liquefied gas are initially heavier than air and spread along ground. · Vapors may travel to source of ignition and flash back. · Runoff may create fire or explosion hazard.
  Emergency Response Guidebook (ERG)

Hazards summary

• Carbon monoxide is a colorless, nonirritating, odorless, and tasteless gas. It is found in both outdoor and indoor air.
  Agency for Toxic Substances and Disease Registry (ATSDR)
• Carboxyhemoglobin 1/2 life in the body = 4 hours in room air and 60-90 minutes in 100% oxygen; Nonsmoker normal = 2%; Smoker = 5-7%; Neurological symptoms = 30%; Death = 40-50%; Carbon monoxide is the most common cause of chemical asphyxia. There is limited positive data that carbon monoxide causes low birth weight and fetal death in humans. In animals, there is strong positive data that it causes birth defects and neonatal mortality and limited positive data that it causes testicular damage. [ATSDR Case Studies, #29] Decreased exercise time to onset of angina or ischemia was observed at COHb levels as low as 3% and increased ventricular arrhythmias at COHb levels of 6%.
  Haz-Map, Information on Hazardous Chemicals and Occupational Diseases

3Composition / information on ingredients

This page describes the pure substance. Commercial products may be solutions or mixtures. Check Section 3 of your supplier's SDS for concentrations and other ingredients.

4First-aid measures

• Excerpt from NIOSH Pocket Guide for Carbon monoxide: Eye: FROSTBITE - If eye tissue is frozen, seek medical attention immediately; if tissue is not frozen, immediately and thoroughly flush the eyes with large amounts of water for at least 15 minutes, occasionally lifting the lower and upper eyelids. If irritation, pain, swelling, lacrimation, or photophobia persist, get medical attention as soon as possible. Skin: FROSTBITE - If frostbite has occurred, seek medical attention immediately; do NOT rub the affected areas or flush them with water. In order to prevent further tissue damage, do NOT attempt to remove frozen clothing from frostbitten areas.
  CAMEO Chemicals
• 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).
  Emergency Response Guidebook (ERG)
• (General first aid procedures) Eye: Frostbite - If eye tissue is frozen, seek medical attention immediately; if tissue is not frozen, immediately and thoroughly flush the eyes with large amounts of water for at least 15 minutes, occasionally lifting the lower and upper eyelids. If irritation, pain, swelling, lacrimation, or photophobia persist, get medical attention as soon as possible. Skin: Frostbite - Compressed gases may create low temperatures when they expand rapidly. Leaks and uses that allow rapid expansion may cause a frostbite hazard. Wear appropriate personal protective clothing to prevent the skin from becoming frozen. Breathing: Respiratory support
  The National Institute for Occupational Safety and Health (NIOSH)

Symptoms of exposure

• Shortness of breath. Headache. Weakness. Irregular heartbeat. Chest pain. Nausea. Dizziness. Unconsciousness.
  ILO-WHO International Chemical Safety Cards (ICSCs)
• headache, tachypnea, nausea, lassitude (weakness, exhaustion), dizziness, confusion, hallucinations; cyanosis; depressed S-T segment of electrocardiogram, angina, syncope
  The National Institute for Occupational Safety and Health (NIOSH)
• Early symptoms of acute carbon monoxide poisoning are nonspecific and include headaches, nausea, and fatigue. Symptoms may progress to tachycardia and hypertension. The central nervous system is one of the organ systems most sensitive to poisoning and symptoms displayed include dizziness, ataxia, confusion, convulsions, unconsciousness, respiratory arrest, and even death. (L961)
  Toxin and Toxin Target Database (T3DB)

5Fire-fighting measures

• Stop flow of gas before extinguishing fire. Use water spray to keep fire-exposed containers cool. Fire situation may require evacuation.
  Hazardous Substances Data Bank (HSDB)
• Use powder or carbon dioxide.
  Hazardous Substances Data Bank (HSDB)
• If material on fire or involved in fire: Do not extinguish fire unless flow can be stopped. Use water in flooding quantities as fog. Cool all affected containers with flooding quantities of water. Apply water from as far a distance as possible.
  Hazardous Substances Data Bank (HSDB)

6Accidental release measures

Isolation and evacuation

• Excerpt from ERG Guide 119 [Gases - Toxic - Flammable]: IMMEDIATE PRECAUTIONARY MEASURE: Isolate spill or leak area for at least 100 meters (330 feet) in all directions. SPILL: See ERG Table 1 - Initial Isolation and Protective Action Distances on the UN/NA 1016 datasheet. FIRE: If tank, rail tank car or highway tank is involved in a fire, ISOLATE for 1600 meters (1 mile) in all directions; also, consider initial evacuation for 1600 meters (1 mile) in all directions. (ERG, 2024)
  CAMEO Chemicals
• Excerpt from ERG Guide 168 [Carbon Monoxide (Refrigerated Liquid)]: IMMEDIATE PRECAUTIONARY MEASURE: Isolate spill or leak area for at least 100 meters (330 feet) in all directions. SPILL: See ERG Table 1 - Initial Isolation and Protective Action Distances on the UN/NA 9202 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)
  CAMEO Chemicals

Spill cleanup

• Evacuate danger area! Consult an expert! Personal protection: self-contained breathing apparatus. Remove all ignition sources. Ventilation.
  ILO-WHO International Chemical Safety Cards (ICSCs)
• 1. Ventilate area of leak or release to disperse gas. 2. Stop flow of gas. If source of leak is a cylinder and the leak cannot be stopped in place, remove the leaking cylinder to a safe place in the open air and repair the leak or allow the cylinder to empty.
  Hazardous Substances Data Bank (HSDB)
• Use water spray to cool and disperse vapors and protect personnel. With cryogenic liquids, releases may require isolation or evacuation.
  Hazardous Substances Data Bank (HSDB)
• Gas leakage: By forced ventilation, maintain concentration of gas below the range of explosive mixture. Remove the tank or cylinder to an open area. Leave to bleed off in the atmosphere.
  Hazardous Substances Data Bank (HSDB)

7Handling and storage

• Fireproof. Cool. Keep in a well-ventilated room.
  ILO-WHO International Chemical Safety Cards (ICSCs)
• Store in a cool, dry, well-ventilated location.
  Hazardous Substances Data Bank (HSDB)
• Remove the sources of ignition. Electric installation should be explosion-proof construction. Protect container against sunlight, and store in well-ventilated, safe areas.
  Hazardous Substances Data Bank (HSDB)

8Exposure controls / personal protection

Personal protective equipment

• Excerpt from NIOSH Pocket Guide for Carbon monoxide: Skin: FROSTBITE - Compressed gases may create low temperatures when they expand rapidly. Leaks and uses that allow rapid expansion may cause a frostbite hazard. Wear appropriate personal protective clothing to prevent the skin from becoming frozen. Eyes: FROSTBITE - Wear appropriate eye protection to prevent eye contact with the liquid that could result in burns or tissue damage from frostbite. Wash skin: No recommendation is made specifying the need for washing the substance from the skin (either immediately or at the end of the work shift).
  CAMEO Chemicals
• Compressed gases may create low temperatures when they expand rapidly. Leaks and uses that allow rapid expansion may cause a frostbite hazard. Wear appropriate personal protective clothing to prevent the skin from becoming frozen. Wear appropriate personal protective clothing to prevent the skin from becoming frozen.
  Hazardous Substances Data Bank (HSDB)
• Wear appropriate eye protection to prevent eye contact with the liquid that could result in burns or tissue damage from frostbite.
  Hazardous Substances Data Bank (HSDB)
• Quick drench facilities and/or eyewash fountains should be provided within the immediate work area for emergency use where there is any possibility of exposure to liquids that are extremely cold or rapidly evaporating.
  Hazardous Substances Data Bank (HSDB)

Respirator recommendations

• NIOSH Up to 350 ppm: (APF = 10) Any supplied-air respirator Up to 875 ppm: (APF = 25) Any supplied-air respirator operated in a continuous-flow mode Up to 1200 ppm: (APF = 50) Any air-purifying, full-facepiece respirator (gas mask) with a chin-style, front- or back-mounted canister providing protection against the compound of concern† (APF = 50) Any self-contained breathing apparatus with a full facepiece (APF = 50) Any supplied-air respirator with a full facepiece Emergency or planned entry into unknown concentrations or IDLH conditions: (APF = 10,000) Any self-contained breathing apparatus that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode (APF =…
  The National Institute for Occupational Safety and Health (NIOSH)

9Physical and chemical properties

10Stability and reactivity

Reactivity

• Bromine trifluoride and carbon monoxide react explosively at high temperatures or concentrations [Mellor 2 Supp. 1:166 1956]. The same is true for various oxidizers such as: chlorine dioxide, oxygen (liquid), peroxodisulfuryl difluoride. The product of the reaction between lithium and carbon monoxide, lithium carbonyl, detonates violently with water, igniting the gaseous products [Mellor 2, Supp. 2:84 1961]. Potassium and sodium metals behave similarly. Cesium oxide, iron(III) oxide, and silver oxide all react, in the presence of moisture, at ambient temperatures with carbon monoxide causing ignition, [Mellor, 1941, vol. 2, 487].
  CAMEO Chemicals
• Contact of very cold liquefied gas with water may result in vigorous or violent boiling and extremely rapid vaporization. If the water is hot, a liquid "superheat" explosion may occur. Pressures may build to dangerous levels if the liquid contacts water in a closed container [Handling Chemicals Safely 1980]. Reacts explosively with bromine trifluoride at high temperatures or concentrations [Mellor 2, Supp. 1:166 1956]. The same is true for various oxidizers such as: chlorine dioxide, oxygen (liquid), peroxodisulfuryl difluoride. Reacts with lithium to give lithium carbonyl, which detonates violently with water, igniting the gaseous products [Mellor 2, Supp 2:84 1961].
  CAMEO Chemicals
• Highly flammable.
  CAMEO Chemicals

Incompatible materials and hazardous reactions

• May react vigorously with oxygen, acetylene, chlorine, fluorine, nitrous oxide.
  Hazardous Substances Data Bank (HSDB)
• Strong oxidizers, bromine trifluoride, chlorine trifluoride, lithium.
  Hazardous Substances Data Bank (HSDB)
• ... Explosion /occurred/ during reduction of iron oxide with carbon monoxide /due to/ formation of pentacarbonyliron at temperatures between 0 and 150 °C.
  Hazardous Substances Data Bank (HSDB)

11Toxicological information

Target organs

• Cardiovascular (Heart and Blood Vessels), Death, Developmental (effects while organs are developing), Hematological (Blood Forming), Neurological (Nervous System), Respiratory (From the Nose to the Lungs)
  Agency for Toxic Substances and Disease Registry (ATSDR)
• cardiovascular system, lungs, blood, central nervous system
  The National Institute for Occupational Safety and Health (NIOSH)

Short-term exposure effects

• The substance may cause effects on the blood. This may result in carboxyhaemoglobinemia and cardiac disorders. Medical observation is indicated. Exposure at high levels could cause death.
  ILO-WHO International Chemical Safety Cards (ICSCs)

Long-term exposure effects

• The substance may have effects on the cardiovascular system and central nervous system. This may result in cardiovascular disorders and nervous system impairment. May cause toxicity to human reproduction or development.
  ILO-WHO International Chemical Safety Cards (ICSCs)

12Ecological information

Not available in the public sources we compile. Check Section 12 of the supplier's SDS.

13Disposal considerations

• SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational harm/injury/toxicity or environmental contamination. Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in soil or water; effects on animal and plant life; and conformance with environmental and public health regulations.
  Hazardous Substances Data Bank (HSDB)
• Incineration: Remove leaky cylinders to remote area to empty; then return to supplier with label indicating that repairs are needed. The waste carbon monoxide can be piped to an approved incinerator or the cylinder can be placed in a pit to burn carbon monoxide to carbon dioxide under controlled conditions.
  Hazardous Substances Data Bank (HSDB)

14Transport information

UN number: UN 1016

Shipping name

• IMO 2.3; Carbon monoxide, compressed; Carbon monoxide, refrigerated liquid (cryogenic liquid)
  Hazardous Substances Data Bank (HSDB)
• NA 9202; Carbon monoxide, refrigerated liquid (cryogenic liquid)
  Hazardous Substances Data Bank (HSDB)

DOT hazard class

• Carbon monoxide, compressed
  US Code of Federal Regulations, Hazardous Materials, 49 CFR Part 172
• UN1016
  US Code of Federal Regulations, Hazardous Materials, 49 CFR Part 172
• Div 2.3 Poisonous gas (49 eCFR § 173.115)
  US Code of Federal Regulations, Hazardous Materials, 49 CFR Part 172

DOT label

• Poison Gas Flammable Gas
  CAMEO Chemicals

UN classification

• UN Hazard Class: 2.3; UN Subsidiary Risks: 2.1
  ILO-WHO International Chemical Safety Cards (ICSCs)

Emergency Response Guidebook

• 9202 168
  Emergency Response Guidebook (ERG)
• 1016 119
  Emergency Response Guidebook (ERG)

How DOT hazard classes work →

15Regulatory information

No specific US regulatory listings found in our sources. Check Section 15 of your supplier's SDS for TSCA, SARA 313, CERCLA, Prop 65 and state listings.

Overview of SDS regulations (OSHA HazCom, WHMIS, REACH/CLP) →

16Other information

Compiled from PubChem CID 281 and the sources it aggregates (attributed inline). Data retrieved 2026-10-12. This summary describes the pure substance and is not a supplier SDS.