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Carbon monoxide

RTECS #
FG3500000
CAS #
630-08-0
See: NMAM or OSHA Methods
Updated
March 2019
Molecular Weight
28.01
Molecular Formula
CO
Synonyms
Carbon monoxide (ACGIH:OSHA)
Carbon oxide (CO)
Carbone (oxyde de) (French)
Carbonic oxide
Carbonio (ossido di) (Italian)
CO
Exhaust gas
Flue gas
Kohlenmonoxid (German)
Kohlenoxyd (German)
Koolmonoxyde (Dutch)
Oxyde de carbone (French)
Wegla tlenek (Polish)

Mutation Data and Reference

System TestRoute/Organism/TissueDoseReference
micronucleus testinhalation/mouse1500 ppm/10MYOMJA9 27,205,1986
sister chromatid exchangeinhalation/mouse2500 ppm/10MYOMJA9 27,205,1986

Reproductive Effects Data and References

Route/OrganismDoseEffectReference
inhalation/rat 75 ppm/24H (0-20D pregnant)Reproductive: Other effects on female

Reproductive: Effects on newborn: Behavioral
BRREAP 844,201,1999
inhalation/rat 150 ppm/24H (1-22D pregnant)Reproductive: Specific developmental abnormalities: Cardiovascular (circulatory) systemTXAPA9 56,370,1980
inhalation/rat 150 ppm/24H (1-22D pregnant)Reproductive: Effects on newborn: Growth statistics (e.g., reduced weight gain)

Reproductive: Effects on newborn: Behavioral
NETOD7 2,7,1980
inhalation/rat 1 mg/m3/24H (72D prior to copulation)Reproductive: Maternal effects: Menstrual cycle changes or disorders

Reproductive: Maternal effects: Parturition

Reproductive: Effects on fertility: Female fertility index (e.g., # females pregnant per # sperm positive females; # females pregnant per # females mated)
HYSAAV 35(4-6),277,1970
inhalation/rat 150 ppm/24H (0-20D pregnant)Reproductive: Effects on newborn: BehavioralLIFSAK 59,1553,1996
inhalation/rat 75 ppm/24H (0-20D pregnant)Reproductive: Specific developmental abnormalities: Immune and reticuloendothelial systemPHTOEH 73,274,1993
inhalation/rat 150 ppm (0-20D pregnant)Reproductive: Other effects on female

Reproductive: Effects on newborn: Biochemical and metabolic

Reproductive: Effects on newborn: Physical
JPETAB 294,728,2000
inhalation/mouse 65 ppm/24H (7-18D pregnant)Reproductive: Effects on newborn: BehavioralTJADAB 29(2),8B,1984
inhalation/mouse 250 ppm/7H (6-15D pregnant)Reproductive: Effects on fertility: Post- implantation mortality (e.g., dead and/or resorbed implants per total number of implants)

Reproductive: Specific developmental abnormalities: Musculoskeletal system
TJADAB 19,385,1979
inhalation/mouse 125 ppm/24H (7-18D pregnant)Reproductive: Effects on embryo or fetus: Fetotoxicity (except death, e.g., stunted fetus)TJADAB 30,253,1984
inhalation/mouse 8 pph/1H (8D pregnant)Reproductive: Effects on fertility: Litter size (e.g., # fetuses per litter; measured before birth)

Reproductive: Effects on embryo or fetus: Fetotoxicity (except death, e.g., stunted fetus)

Reproductive: Effects on embryo or fetus: Fetal death
FPNJAG 11,301,1958
inhalation/mouse 8 pph/1H (8D pregnant)Reproductive: Specific developmental abnormalities: Central nervous systemFPNJAG 11,301,1958
inhalation/rabbit 180 ppm/24H (1-30D pregnant)Reproductive: Effects on newborn: Stillbirth

Reproductive: Effects on newborn: Viability index (e.g., # alive at day 4 per # born alive)
LANCAO 2,1220,1972
inhalation/guinea pig 200 ppm/10H (23-61D pregnant)Reproductive: Effects on embryo or fetus: Fetotoxicity (except death, e.g., stunted fetus)

Reproductive: Specific developmental abnormalities: Central nervous system

Reproductive: Specific developmental abnormalities: Hepatobiliary system
JNENAD 59,218,2000
inhalation/rat 103 mg/m3 (1-22D pregnant)Reproductive: Effects on fertility: Litter size (e.g., # fetuses per litter; measured before birth)

Reproductive: Specific developmental abnormalities: Cardiovascular (circulatory) system

Reproductive: Effects on newborn: Growth statistics (e.g., reduced weight gain)
VCVN1* -,318,1988
inhalation/mouse 103 mg/m3 (1-21D pregnant)Reproductive: Effects on fertility: Litter size (e.g., # fetuses per litter; measured before birth)

Reproductive: Specific developmental abnormalities: Cardiovascular (circulatory) system

Reproductive: Effects on newborn: Growth statistics (e.g., reduced weight gain)
VCVN1* -,318,1988
inhalation/guinea pig 550 mg/m3 (20-40D pregnant)Reproductive: Effects on fertility: Abortion

Reproductive: Specific developmental abnormalities: Central nervous system

Reproductive: Effects on newborn: Viability index (e.g., # alive at day 4 per # born alive)
VCVN1* -,318,1988
inhalation/guinea pig 480 mg/m3 (20-50D pregnant)Reproductive: Effects on fertility: Abortion

Reproductive: Specific developmental abnormalities: Central nervous system

Reproductive: Effects on newborn: Viability index (e.g., # alive at day 4 per # born alive)
VCVN1* -,318,1988
inhalation/guinea pig 100 mg/m3 (10W prior to copulation)Reproductive: Effects on fertility: Pre- implantation mortality (e.g., reduction in number of implants per female; total number of implants per corpora lutea)

Reproductive: Effects on fertility: Litter size (e.g., # fetuses per litter; measured before birth)

Reproductive: Effects on newborn: Growth statistics (e.g., reduced weight gain)
VCVN1* -,318,1988
inhalation/guinea pig 100 mg/m3 (10W prior to copulation)Reproductive: Effects on fertility: Post- implantation mortality (e.g., dead and/or resorbed implants per total number of implants)VCVN1* -,318,1988
inhalation/rat 150 ppm (1-20D pregnant)Reproductive: Specific developmental abnormalities: Central nervous systemTOLED5 135,S82,2002
inhalation/mouse 500 ppm (7-18D pregnant)Reproductive: Effects on embryo or fetus: Fetotoxicity (except death, e.g., stunted fetus)

Reproductive: Effects on embryo or fetus: Fetal death
REPTED 20,453,2005
inhalation/mouse 125 ppm (1-7D pregnant)Reproductive: Effects on newborn: Live birth index (Litter size (e.g., # fetuses per litter; measured after birth)

Reproductive: Effects on newborn: Viability index (e.g., # alive at day 4 per # born alive)
REPTED 22,263,2006
inhalation/rat 150 ppm (0-20D pregnant)Reproductive: Specific developmental abnormalities: Central nervous systemNSAPCC 369(Suppl 1),R163,2004
inhalation/mouse 125 ppm (1-14D pregnant)Reproductive: Effects on newborn: Growth statistics (e.g., reduced weight gain)

Reproductive: Effects on newborn: Stillbirth
BDERB* 77,216,2006
inhalation/mouse 65 ppm (1-14D pregnant)Reproductive: Effects on newborn: Viability index (e.g., # alive at day 4 per # born alive)BDERB* 77,216,2006
inhalation/mouse 500 ppm (8-18D pregnant)Reproductive: Effects on embryo or fetus: Fetal death

Reproductive: Specific developmental abnormalities: Gastrointestinal system
BDERB* 68,355,2003
inhalation/mouse 500 ppm (8-18D pregnant)Reproductive: Effects on embryo or fetus: Fetotoxicity (except death, e.g., stunted fetus)

Reproductive: Effects on embryo or fetus: Fetal death
TSPSA* -,255,2003
inhalation/mouse 500 ppm (8-18D pregnant)Reproductive: Specific developmental abnormalities: Musculoskeletal systemTERP2* -,304,2004
inhalation/mouse 150 ppm (7-21D pregnant)Reproductive: Specific developmental abnormalities: Central nervous systemNRTXDN 53,31,2016

Acute Toxicity Data and References

Route/OrganismDoseEffectReference
In Vitro/maaInhibitor Concentration Low: 50 ppm/3DIn Vitro Toxicity Studies: Other assaysNRTXDN 53,31,2016
In Vitro/paaInhibitor Concentration Low: 3000 ppm/30MIn Vitro Toxicity Studies: Other assaysTOLED5 253,1,2016
In Vitro/paaInhibitor Concentration Low: 3000 ppm/8HIn Vitro Toxicity Studies: Cell metabolic activity: Alamar Blue assay etc.

In Vitro Toxicity Studies: Apoptosis in vitro
TOLED5 233,16,2015
inhalation/cat lowest published toxic concentration: 50 mg/m3/60MBehavioral: Alteration of classical conditioningVCVN1* -,308,1988
inhalation/cat lowest published toxic concentration: 2000 mg/m3/20MBehavioral: Alteration of classical conditioningVCVN1* -,308,1988
inhalation/cat Lowest published lethal concentration: 500 mg/m3/30MVCVN1* -,308,1988
inhalation/cat Lowest published lethal concentration: 34400 mg/m3/3MVCVN1* -,308,1988
inhalation/Dog lowest published toxic concentration: 2000 mg/m3/30MBehavioral: Alteration of classical conditioningVCVN1* -,308,1988
inhalation/Dog Lowest published lethal concentration: 23000 mg/m3/20MVCVN1* -,308,1988
inhalation/Dog Lowest published lethal concentration: 4000 ppm/46MHBAMAK 4,1360,1935
inhalation/domestic animal lowest published toxic concentration: 1 pph/45MCardiac: Pulse rate increased without fall in BPTXCYAC 165,97,2001
inhalation/domestic animal lowest published toxic concentration: 1 pph/65MNutritional and Gross Metabolic: Changes in: Metabolic acidosis

Brain and Coverings: Other degenerative changes

Behavioral: Somnolence (general depressed activity)
TXCYAC 165,97,2001
inhalation/domestic animal lowest published toxic concentration: 1 pph/95MBrain and Coverings: Other degenerative changes

Behavioral: Somnolence (general depressed activity)

Nutritional and Gross Metabolic: Body temperature decrease
TXCYAC 165,97,2001
inhalation/domestic animal lowest published toxic concentration: 1 pph/100MBrain and Coverings: Other degenerative changes

Behavioral: Somnolence (general depressed activity)

Nutritional and Gross Metabolic: Body temperature decrease
TXCYAC 165,97,2001
inhalation/domestic animal lowest published toxic concentration: 1 pph/120MBrain and Coverings: Other degenerative changes

Behavioral: Somnolence (general depressed activity)

Nutritional and Gross Metabolic: Body temperature decrease
TXCYAC 165,97,2001
inhalation/domestic animal lowest published toxic concentration: 1 pph/150MBrain and Coverings: Other degenerative changes

Behavioral: Somnolence (general depressed activity)

Nutritional and Gross Metabolic: Body temperature decrease
TXCYAC 165,97,2001
inhalation/domestic animal lowest published toxic concentration: 1 pphBrain and Coverings: Changes in surface EEG

Behavioral: Somnolence (general depressed activity)

Biochemical: Enzyme inhibition, induction, or change in blood or tissue levels: Multiple enzyme effects
TXCYAC 179,79,2002
inhalation/domestic animal lowest published toxic concentration: 1 pph/120MBrain and Coverings: Other degenerative changes

Behavioral: Somnolence (general depressed activity)

Biochemical: Enzyme inhibition, induction, or change in blood or tissue levels: Multiple enzyme effects
TXCYAC 186,143,2003
inhalation/domestic animal Lowest published lethal concentration: 1 pph/2HBrain and Coverings: Changes in surface EEG

Brain and Coverings: Other degenerative changes

Behavioral: General anesthetic
TXCYAC 209,237,2005
inhalation/guinea pig lethal concentration (50 percent kill): 5718 ppm/4HTXAPA9 17,752,1970
inhalation/guinea pig lowest published toxic concentration: 2000 mg/m3/30MBehavioral: Alteration of classical conditioningVCVN1* -,309,1988
inhalation/guinea pig Lowest published lethal concentration: 4600 mg/m3/2HVCVN1* -,309,1988
inhalation/guinea pig Lowest published lethal concentration: 10300 mg/m3/60MVCVN1* -,309,1988
inhalation/human Lowest published lethal concentration: 5000 ppm/5MTABIA2 3,231,1933
inhalation/human Lowest published lethal concentration: 4 mg/m3/12HBehavioral: Coma

Vascular: BP lowering not characterized in autonomic section

Blood: Methemoglobinemia- Carboxhemoglobinemia
TOVEFN (4),26,1999
inhalation/human lowest published toxic concentration: 600 mg/m3/10MBehavioral: HeadacheGTPZAB 31(4),34,1987
inhalation/human lowest published toxic concentration: 6 mg/m3/25MEye: Other eye effectsVCVN1* -,313,1988
inhalation/human lowest published toxic concentration: 11 mg/m3/5HBehavioral: Alteration of classical conditioningVCVN1* -,313,1988
inhalation/human lowest published toxic concentration: 31 mg/m3/3HEye: Visual field changesVCVN1* -,313,1988
inhalation/human lowest published toxic concentration: 33 mg/m3/6HBlood: Changes in serum composition (e.g. TP, bilirubin, cholesterol)VCVN1* -,313,1988
inhalation/human lowest published toxic concentration: 50 mg/m3/2HEar: Change in acuity

Brain and Coverings: Changes in surface EEG
VCVN1* -,313,1988
inhalation/human lowest published toxic concentration: 50 mg/m3/5HBehavioral: Change in psychophysiological testsVCVN1* -,313,1988
inhalation/human lowest published toxic concentration: 55 mg/m3/8HEye: Other eye effectsVCVN1* -,313,1988
inhalation/human lowest published toxic concentration: 60 mg/m3/6HCardiac: Pulse rate decreased with fall in BP

Brain and Coverings: Changes in surface EEG
VCVN1* -,313,1988
inhalation/human lowest published toxic concentration: 80 mg/m3/3HEye: Other eye effects

Behavioral: Change in psychophysiological tests

Behavioral: Ataxia
VCVN1* -,313,1988
inhalation/human lowest published toxic concentration: 220 mg/m3/1HBehavioral: HeadacheVCVN1* -,314,1988
inhalation/human lowest published toxic concentration: 220 mg/m3/3HBehavioral: Somnolence (general depressed activity)VCVN1* -,314,1988
inhalation/human lowest published toxic concentration: 230 mg/m3/6HBrain and Coverings: Increased intracranial pressure

Behavioral: Somnolence (general depressed activity)
VCVN1* -,314,1988
inhalation/human lowest published toxic concentration: 440 mg/m3/4HBehavioral: Headache

Gastrointestinal: Nausea or vomiting
VCVN1* -,314,1988
inhalation/human lowest published toxic concentration: 440 mg/m3/1HBehavioral: Headache

Cardiac: Pulse rate increased without fall in BP
VCVN1* -,314,1988
inhalation/human lowest published toxic concentration: 460 mg/m3/4HBehavioral: Headache

Behavioral: Somnolence (general depressed activity)

Vascular: BP lowering not characterized in autonomic section
VCVN1* -,314,1988
inhalation/human lowest published toxic concentration: 660 mg/m3/2HGastrointestinal: Nausea or vomitingVCVN1* -,314,1988
inhalation/human lowest published toxic concentration: 660 mg/m3/4HBehavioral: General anestheticVCVN1* -,314,1988
inhalation/human lowest published toxic concentration: 800 mg/m3/5MBehavioral: Headache

Behavioral: Somnolence (general depressed activity)
VCVN1* -,314,1988
inhalation/human lowest published toxic concentration: 800 mg/m3/20MGastrointestinal: Nausea or vomiting

Behavioral: Muscle weakness
VCVN1* -,314,1988
inhalation/human lowest published toxic concentration: 800 mg/m3/3HCardiac: Pulse rate increased without fall in BP

Vascular: BP lowering not characterized in autonomic section
VCVN1* -,314,1988
inhalation/human lowest published toxic concentration: 880 mg/m3/2HBehavioral: Somnolence (general depressed activity)

Behavioral: General anesthetic

Vascular: BP lowering not characterized in autonomic section
VCVN1* -,315,1988
inhalation/human Lowest published lethal concentration: 880 mg/m3/4HBehavioral: Tetany

Behavioral: Coma
VCVN1* -,315,1988
inhalation/human lowest published toxic concentration: 1260 mg/m3/90MCardiac: Pulse rate increased without fall in BP

Behavioral: Coma

Behavioral: Tetany
VCVN1* -,315,1988
inhalation/human lowest published toxic concentration: 1300 mg/m3/2HGastrointestinal: Nausea or vomiting

Cardiac: Pulse rate increased without fall in BP

Behavioral: Headache
VCVN1* -,315,1988
inhalation/human lowest published toxic concentration: 1350 mg/m3/33MCardiac: Pulse rate increased without fall in BP

Eye: Other eye effects

Behavioral: Alteration of classical conditioning
VCVN1* -,315,1988
inhalation/human lowest published toxic concentration: 1760 mg/m3/20MBehavioral: Headache

Gastrointestinal: Nausea or vomiting
VCVN1* -,315,1988
inhalation/human lowest published toxic concentration: 1760 mg/m3/2HBehavioral: General anesthetic

Vascular: BP lowering not characterized in autonomic section
VCVN1* -,315,1988
inhalation/human Lowest published lethal concentration: 1800 mg/m3/1HLung, Thorax, or Respiration: Respiratory depression

Cardiac: Change in force of contraction
VCVN1* -,315,1988
inhalation/human lowest published toxic concentration: 2000 mg/m3/12MBehavioral: Tetany

Behavioral: Coma
VCVN1* -,315,1988
inhalation/human Lowest published lethal concentration: 3000 mg/m3/1HVCVN1* -,315,1988
inhalation/human Lowest published lethal concentration: 2300 mg/m3/30MBehavioral: General anesthetic

Vascular: BP lowering not characterized in autonomic section
VCVN1* -,315,1988
inhalation/human lowest published toxic concentration: 3520 mg/m3/5MBehavioral: HeadacheVCVN1* -,315,1988
inhalation/human lowest published toxic concentration: 3520 mg/m3/30MBehavioral: General anesthetic

Gastrointestinal: Nausea or vomiting
VCVN1* -,315,1988
inhalation/human Lowest published lethal concentration: 3400 mg/m3/20MCardiac: Pulse rate decreased with fall in BP

Lung, Thorax, or Respiration: Respiratory depression
VCVN1* -,315,1988
inhalation/human lowest published toxic concentration: 5000 mg/m3/17MBehavioral: General anesthetic

Behavioral: Tetany
VCVN1* -,315,1988
inhalation/human Lowest published lethal concentration: 5700 mg/m3/2MVCVN1* -,315,1988
inhalation/human Lowest published lethal concentration: 14080 mg/m3/1MGastrointestinal: Nausea or vomiting

Behavioral: General anesthetic
VCVN1* -,315,1988
inhalation/mammal (species unspecified) Lowest published lethal concentration: 5000 ppm/5MAEPPAE 138,65,1928
inhalation/man Lowest published lethal concentration: 4000 ppm/30M29ZWAE -,207,1968
inhalation/man lowest published toxic concentration: 650 ppm/45MBlood: Methemoglobinemia- Carboxhemoglobinemia

Behavioral: Change in psychophysiological tests
AIHAAP 34,212,1973
inhalation/monkey lowest published toxic concentration: 1145 mg/m3/30MCardiac: Other changes

Liver: Multiple effects

Lung, Thorax, or Respiration: Other changes
VCVN1* -,309,1988
inhalation/mouse lethal concentration (50 percent kill): 2444 ppm/4HTXAPA9 17,752,1970
inhalation/mouse lethal concentration (50 percent kill): 2230 mg/m3/2HVCVN1* -,308,1988
inhalation/mouse Lowest published lethal concentration: 1900 mg/m3/2HVCVN1* -,308,1988
inhalation/mouse lowest published toxic concentration: 1000 ppm/1HBrain and Coverings: Recordings from specific areas of CNSTXAPA9 273,410,2013
inhalation/mouse lowest published toxic concentration: 100 ppm/1HBlood: Other changes

Biochemical: Metabolism (intermediary): Effect on inflammation or mediation of inflammation
TXAPA9 273,410,2013
inhalation/mouse lowest published toxic concentration: 5 ppm/1HBehavioral: Alteration of classical conditioningNETEEC 61,92,2017
inhalation/mouse lowest published toxic concentration: 1000 ppm/40MBrain and Coverings: Changes in circulation

Vascular: Measurement of regional blood flow

Biochemical: Enzyme inhibition, induction, or change in blood or tissue levels: Other oxidoreductases
TXAPA9 194,280,2004
inhalation/rabbit Lowest published lethal concentration: 4000 ppmHBAMAK 4,1360,1935
inhalation/rabbit lowest published toxic concentration: 100 mg/m3/2HPeripheral Nerve and Sensation: Recording from peripheral motor nerveVCVN1* -,309,1988
inhalation/rabbit lowest published toxic concentration: 6600 mg/m3/10MLung, Thorax, or Respiration: Acute pulmonary edemaVCVN1* -,309,1988
inhalation/rabbit Lowest published lethal concentration: 17200 mg/m3/40MVCVN1* -,309,1988
inhalation/rabbit Lowest published lethal concentration: 20000 mg/m3/60MVCVN1* -,309,1988
inhalation/rat lethal concentration (50 percent kill): 1807 ppm/4HTXAPA9 17,752,1970
inhalation/rat lowest published toxic concentration: 40 mg/m3/4HBlood: Changes in serum composition (e.g. TP, bilirubin, cholesterol)VCVN1* -,308,1988
inhalation/rat lowest published toxic concentration: 88 mg/m3/20MNutritional and Gross Metabolic: Changes in: PVCVN1* -,308,1988
inhalation/rat lowest published toxic concentration: 176 mg/m3/20MBrain and Coverings: Other degenerative changesVCVN1* -,308,1988
inhalation/rat lowest published toxic concentration: 800 mg/m3/4HBehavioral: Altered sleep time (including change in righting reflex)VCVN1* -,308,1988
inhalation/rat lethal concentration (50 percent kill): 1900 mg/m3/4HVCVN1* -,308,1988
inhalation/rat lowest published toxic concentration: 2000 mg/m3/11MBehavioral: Alteration of classical conditioningVCVN1* -,308,1988
inhalation/rat lethal concentration (50 percent kill): 13500 mg/m3/15MVCVN1* -,308,1988
inhalation/rat lowest published toxic concentration: 1000 ppm/5MLung, Thorax, or Respiration: Respiratory stimulation

Blood: Other changes
TOXID9 72,297,2003
inhalation/rat lowest published toxic concentration: 0.3 pph/40MBehavioral: Somnolence (general depressed activity)

Blood: Methemoglobinemia- Carboxhemoglobinemia

Biochemical: Neurotransmitters or modulators (putative): Dopamine in striatum
ARTODN 76,596,2002
inhalation/rat lowest published toxic concentration: 1000 ppmBlood: Other changesTOXID9 66,345,2002
inhalation/rat Lowest published lethal concentration: 12000 ppmTOXID9 66,345,2002
inhalation/rat lethal concentration (50 percent kill): 6600 ppm/30MENTOX* -,639,2005
inhalation/rat lowest published toxic dose: 3000 ppm/60MBrain and Coverings: Other degenerative changesTXCYAC 225,138,2006
inhalation/rat lowest published toxic dose: 24000 ppm/4MLung, Thorax, or Respiration: Respiratory depressionINHTE5 17,755,2005
inhalation/rat lethal dose (30 percent kill): 24000 ppm/5MLung, Thorax, or Respiration: Respiratory obstruction

Blood: Other changes

Nutritional and Gross Metabolic: Changes in: Metabolic acidosis
INHTE5 17,755,2005
inhalation/rat lowest published toxic dose: 500 ppm/5MBlood: Methemoglobinemia- CarboxhemoglobinemiaINHTE5 17,755,2005
inhalation/rat lowest published toxic concentration: 24000 ppm/4MLung, Thorax, or Respiration: Respiratory depressionINHTE5 17,755,2005
inhalation/rat lethal concentration (30 percent kill): 24000 ppm/5MLung, Thorax, or Respiration: Respiratory obstruction

Blood: Other changes

Nutritional and Gross Metabolic: Changes in: Metabolic acidosis
INHTE5 17,755,2005
inhalation/rat lowest published toxic concentration: 500 ppm/5MBlood: Methemoglobinemia- CarboxhemoglobinemiaINHTE5 17,755,2005
inhalation/rat lowest published toxic concentration: 2000 ppm/60MBehavioral: General anestheticTOLED5 170,111,2007
inhalation/rat lowest published toxic concentration: 2000 ppm/120MBehavioral: Alteration of operant conditioningTOLED5 170,111,2007
inhalation/rat lowest published toxic concentration: 2 pph/10MCardiac: Other changesBCLPT* 98,565,2006
inhalation/rat lowest published toxic concentration: 4000 mg/m3/90MBlood: Methemoglobinemia- Carboxhemoglobinemia

Blood: Other changes

Biochemical: Metabolism (intermediary): Lipids including transport
TOVEFN (6),2,2006
inhalation/rat Lowest published lethal concentration: 3000 ppm/40MBrain and Coverings: Other degenerative changes

Biochemical: Enzyme inhibition, induction, or change in blood or tissue levels: Other enzymes

Biochemical: Metabolism (intermediary): Lipids including transport
TXCYAC 262,146,2009
inhalation/rat lowest published toxic concentration: 3000 ppm/40MBrain and Coverings: Other degenerative changesTXCYAC 264,69,2009
inhalation/rat lowest published toxic concentration: 3000 ppm/1HBrain and Coverings: Other degenerative changes

Biochemical: Enzyme inhibition, induction, or change in blood or tissue levels: Other oxidoreductases
FCTOD7 86,56,2015
inhalation/rat Lowest published lethal concentration: 3000 ppm/1HFCTOD7 86,56,2015
inhalation/rat Lowest published lethal concentration: 5200 mg/m3/1HVCVN1* -,308,1988
inhalation/rat lowest published toxic concentration: 3000 ppm/40MBrain and Coverings: Other degenerative changes

Biochemical: Metabolism (intermediary): Effect on cyclic nucleotides
TXCYAC 288,49,2011
inhalation/rat lowest published toxic concentration: 1000 ppm/40MBrain and Coverings: Changes in circulation

Vascular: Measurement of regional blood flow

Biochemical: Metabolism (intermediary): Amino acids (including renal excretion)
TXAPA9 194,280,2004
inhalation/rat lowest published toxic concentration: 1005 ppm/90MBrain and Coverings: Recordings from specific areas of CNSTOLED5 145,101,2003
inhalation/rat lowest published toxic concentration: 50 ppm/2HBlood: Methemoglobinemia- CarboxhemoglobinemiaTXCYAC 194,51,2003
inhalation/rat lowest published toxic concentration: 4000 ppm/15MBrain and Coverings: Other degenerative changes

Behavioral: Alteration of classical conditioning

Blood: Methemoglobinemia- Carboxhemoglobinemia
TXCYAC 194,51,2003
inhalation/wild bird lethal concentration (50 percent kill): 1334 ppmAECTCV 12,355,1983
intraperitoneal/mouse lowest published toxic dose: 2240.8 µg/kgBiochemical: Metabolism (intermediary): Effect on inflammation or mediation of inflammationJPETAB 319,1265,2006
intraperitoneal/rat lowest published toxic dose: 35 mL/kgEar: Change in cochlear structure or functionNETEEC 23,157,2001

Other Multiple Dose Data and References

Route/OrganismDoseEffectReference
inhalation/guinea pig lowest published toxic concentration: 200 mg/m3/5H/4W- intermittentEndocrine: HyperglycemiaGISAAA 30(5),30,1965
inhalation/guinea pig lowest published toxic concentration: 200 mg/m3/5H/30W- intermittentCardiac: Arrythmias (indlucing changes in conduction)

Cardiac: EKG changes not diagnostic of above

Cardiac: Pulse rate increased without fall in BP
GISAAA 31(3),102,1966
inhalation/guinea pig lowest published toxic concentration: 200 ppm/24H/90D- continuousBlood: Pigmented or nucleated red blood cells

Blood: Other changes
TXAPA9 19,46,1971
inhalation/guinea pig lowest published toxic concentration: 100 mg/m3/10W- continuousEndocrine: Effect on menstrual cycleVCVN1* -,318,1988
inhalation/guinea pig lowest published toxic concentration: 16 pph/48H-continuousBrain and Coverings: Other degenerative changes

Liver: Other changes

Kidney, Ureter, and Bladder: Other changes
VCVN1* -,329,1988
inhalation/man lowest published toxic concentration: 2 pph/30D- intermittentBehavioral: Somnolence (general depressed activity)VCVN1* -,329,1988
inhalation/monkey lowest published toxic concentration: 200 ppm/24H/90D- continuousBlood: Pigmented or nucleated red blood cells

Blood: Other changes
TXAPA9 19,46,1971
inhalation/monkey lowest published toxic concentration: 110 mg/m3/90D- intermittentCardiac: Other changesVCVN1* -,316,1988
inhalation/mouse lowest published toxic concentration: 50 ppm/30D- intermittentLung, Thorax, or Respiration: Structural or functional change in trachea or bronchiNKYZA2 10,16,1972
inhalation/mouse lowest published toxic concentration: 10 mg/m3/4H/10W- intermittentBrain and Coverings: Other degenerative changes

Cardiac: Other changes

Endocrine: Other changes
VCVN1* -,316,1988
inhalation/rabbit lowest published toxic concentration: 200 mg/m3/3H/13W- intermittentBrain and Coverings: Other degenerative changes

Cardiac: Other changes

Blood: Hemorrhage
GISAAA 24(6),22,1959
inhalation/rabbit lowest published toxic concentration: 50 ppm/24H/8W- continuousBlood: Changes in platelet countJEPTDQ 4(1),351,1980
inhalation/rabbit lowest published toxic concentration: 110 mg/m3/1Y- intermittentBlood: Changes in serum composition (e.g. TP, bilirubin, cholesterol)VCVN1* -,316,1988
inhalation/rabbit lowest published toxic concentration: 170 mg/m3/45D- intermittentVascular: Structural changes in vesselsVCVN1* -,316,1988
inhalation/rabbit lowest published toxic concentration: 4.5 pph/13D- continuousBrain and Coverings: Other degenerative changes

Liver: Other changes

Kidney, Ureter, and Bladder: Other changes
VCVN1* -,329,1988
inhalation/rat lowest published toxic concentration: 10 mg/m3/4H/10W- intermittentBrain and Coverings: Other degenerative changes

Cardiac: Other changes

Endocrine: Other changes
VCVN1* -,316,1988
inhalation/rat lowest published toxic concentration: 53 mg/m3/30D- continuousLiver: Other changes

Blood: Changes in cell count (unspecified)

Nutritional and Gross Metabolic: Weight loss or decreased weight gain
VCVN1* -,316,1988
inhalation/rat lowest published toxic concentration: 100 mg/m3/1W- continuousLiver: Other changes

Blood: Changes in cell count (unspecified)

Nutritional and Gross Metabolic: Weight loss or decreased weight gain
VCVN1* -,316,1988
inhalation/rat lowest published toxic concentration: 105 ppm/7D- continuousCardiac: Cardiomegaly

Blood: Other changes

Cardiac: Change in force of contraction
ETOPFR 8,23,1999
inhalation/rat lowest published toxic concentration: 315 ppm/21D- continuousCardiac: Changes in coronary arteries

Cardiac: Arrythmias (indlucing changes in conduction)
ETOPFR 8,23,1999
inhalation/rat lowest published toxic concentration: 1800 ppm/1H/14D- intermittentCardiac: Other changesTOPADD 15,366,1987
inhalation/rat lowest published toxic concentration: 30 mg/m3/8H/10W- intermittentBrain and Coverings: Other degenerative changes

Behavioral: Muscle contraction or spasticity
GISAAA 26(3),3,1961
inhalation/rat lowest published toxic concentration: 96 ppm/24H/90D- continuousBlood: Pigmented or nucleated red blood cells

Blood: Other changes
TXAPA9 19,46,1971
inhalation/rat lowest published toxic concentration: 250 ppm/5H/20D- intermittentBlood: Pigmented or nucleated red blood cells

Blood: Changes in other cell count (unspecified)

Blood: Changes in erythrocyte (RBC) count
BECTA6 13,537,1975
inhalation/rat lowest published toxic concentration: 375 mg/m3/5H/20W- intermittentVascular: Structural changes in vessels

Blood: Changes in serum composition (e.g. TP, bilirubin, cholesterol)

Blood: Other changes
WDZAEK 6,133,1992
intraperitoneal/mouse lowest published toxic dose: 700 mL/kg/7D- intermittentBrain and Coverings: Recordings from specific areas of CNS

Behavioral: Change in psychophysiological tests

Related to Chronic Data: Death in the "MULTIPLE DOSE" data type field
CYLPDN 21,360,2000
intraperitoneal/mouse lowest published toxic dose: 700 mL/kg/7D- intermittentBrain and Coverings: Other degenerative changes

Behavioral: Change in psychophysiological tests

Related to Chronic Data: Death in the "MULTIPLE DOSE" data type field
CYLPDN 22,423,2001
subcutaneous/rat lowest published toxic dose: 5983 mg/kg/18W- intermittentBlood: Changes in serum composition (e.g. TP, bilirubin, cholesterol)TOLED5 1,275,1978

Reviews

OrganizationStandardReference
American Conference of Governmental Industrial Hygienists (ACGIH)Threshold Limit Value-time-weighted average 25 ppmDTLVS* TLV/BEI,2013
TOXICOLOGY REVIEWENVRAL 10,236,1975
TOXICOLOGY REVIEWEVHPAZ 11,163,1975
TOXICOLOGY REVIEWAOHYA3 17,143,1974
TOXICOLOGY REVIEWCLCHAU 19,361,1973
TOXICOLOGY REVIEWAJMEAZ 38,409,1965
TOXICOLOGY REVIEWFNSCA6 2,67,1973
TOXICOLOGY REVIEWAOHYA3 17,159,1974
TOXICOLOGY REVIEWNTIS** CONF-691001
TOXICOLOGY REVIEWBPAAAG 135,350,1967
TOXICOLOGY REVIEWJTCTDW 39,1,2001
TOXICOLOGY REVIEWTXCYAC 187,25,2003
TOXICOLOGY REVIEWMUREAV 558,7,2004
TOXICOLOGY REVIEWCTOXAO 39,35,2001
TOXICOLOGY REVIEWCMAJAX 166,1685,2002
TOXICOLOGY REVIEWTXCYAC 180,139,2002
TOXICOLOGY REVIEWTOLED5 134,3,2002
TOXICOLOGY REVIEWTOLED5 140-141,183,2003
TOXICOLOGY REVIEWARPTDI 45,147,2005
TOXICOLOGY REVIEWCRTXB2 32,259,2002
TOXICOLOGY REVIEWDIMON* 46,551,2000
TOXICOLOGY REVIEWENTOX* -,639,2005
TOXICOLOGY REVIEWPAREAQ 57,585,2005
TOXICOLOGY REVIEWFSINDR 161,41,2006
TOXICOLOGY REVIEWFSINDR 164,164,2006
TOXICOLOGY REVIEWITODC* -,327,2004
TOXICOLOGY REVIEWHUTOX* -,247,1996
TOXICOLOGY REVIEWHUTOX* -,661,1996
TOXICOLOGY REVIEWMCLNA* 89,1161,2005
TOXICOLOGY REVIEWTPHSDY 29,361,2008
TOXICOLOGY REVIEWMUREAV 674,3,2009
TOXICOLOGY REVIEWMUREAV 674,45,2009
TOXICOLOGY REVIEWMUREAV 636,144,2007
TOXICOLOGY REVIEWMUREAV 636,36,2007
TOXICOLOGY REVIEWPTPAD4 113,229,2007
TOXICOLOGY REVIEWAIRMJ* 21,10,2002
TOXICOLOGY REVIEWCPEMM* 9,43,2008
TOXICOLOGY REVIEWHTCWA* 2,271,
TOXICOLOGY REVIEWJFSCAS 19,211,1979
TOXICOLOGY REVIEWREPTED 29,1,2010
TOXICOLOGY REVIEWNEUCL* 15,711,1997
TOXICOLOGY REVIEWNEUCL* 18,215,2000
TOXICOLOGY REVIEWNCLNA* 16,107,1998
TOXICOLOGY REVIEWNEUCL* 23,485,2005
TOXICOLOGY REVIEWNBREV* 5,1,1981
TOXICOLOGY REVIEWPRESR* 7,123,2006
TOXICOLOGY REVIEWNTAPM* -,265,1995
TOXICOLOGY REVIEWNTAPM* -,617,1995
TOXICOLOGY REVIEWNTAPM* -,629,1995
TOXICOLOGY REVIEWNTAPM* -,671,1995
TOXICOLOGY REVIEWNTAPM* -,689,1995
TOXICOLOGY REVIEWNTAPM* -,711,1995
TOXICOLOGY REVIEWNTAPM* -,747,1995
TOXICOLOGY REVIEWNTAPM* -,753,1995
TOXICOLOGY REVIEWMUREAV 717,38,2011
TOXICOLOGY REVIEWMUREAV 717,46,2011
TOXICOLOGY REVIEWMUTAEX 28,485,2013
TOXICOLOGY REVIEWTOLED5 203,20,2011
TOXICOLOGY REVIEWMUREAV 762,76,2014
TOXICOLOGY REVIEWMUREAV 765,19,2015
TOXICOLOGY REVIEWTXAPA9 275,145,2014
TOXICOLOGY REVIEWFCTOD7 86,298,2015
TOXICOLOGY REVIEWTXCYAC 325,74,2014
TOXICOLOGY REVIEWFCTOD7 94,93,2016
TOXICOLOGY REVIEWNETEEC 52,25,2015
TOXICOLOGY REVIEWNETEEC 52,68,2015
TOXICOLOGY REVIEWTIVIEQ 32,92,2016
TOXICOLOGY REVIEWREPTED 61,120,2016
TOXICOLOGY REVIEWTIVIEQ 36,105,2016
TOXICOLOGY REVIEWTOLED5 262,142,2016
TOXICOLOGY REVIEWNETEEC 60,50,2017
TOXICOLOGY REVIEWRTOPDW 54,247,2009
TOXICOLOGY REVIEWVETODR ,197,2018
TOXICOLOGY REVIEWVETODR ,215,2018

Standards and Regulations

OrganizationStandardReference
Mine Safety and Health Administration (MSHA) STANDARD-airtime-weighted average 50 ppm (55 mg/m3)DTLVS* 3,41,1971
Occupational Exposure Limit IN ARGENTINA, BULGARIA, COLOMBIA, JORDAN check ACGIH TLV;
Occupational Exposure Limit IN SINGAPORE, VIETNAM check ACGIH TLV
Occupational Exposure Limit-ARAB Republic of Egypttime-weighted average 50 ppm (55 mg/m3), JAN1993
Occupational Exposure Limit-AUSTRALIAtime-weighted average 30 ppm (34 mg/m3), JUL2008
Occupational Exposure Limit-AUSTRIAMAK-TMW 30 ppm (33 mg/m3);KZW 60 ppm (66 mg/m3), 2007
Occupational Exposure Limit-BELGIUMtime-weighted average 25 ppm (29 mg/m3), MAR2002
Occupational Exposure Limit-DENMARKtime-weighted average 25 ppm (29 mg/m3), MAY2011
Occupational Exposure Limit-FINLANDtime-weighted average 30 ppm (35 mg/m3), short term exposure limit 75 ppm (87 mg/m3), NOV2011
Occupational Exposure Limit-FRANCEVME 50 ppm (55 mg/m3), FEB2006
Occupational Exposure Limit-GERMANYMAK 30 ppm (35 mg/m3), 2011
Occupational Exposure Limit-HUNGARYtime-weighted average 33 mg/m3, short term exposure limit 132 mg/m3, SEP2000
Occupational Exposure Limit-ICELANDtime-weighted average 25 ppm (29 mg/m3), NOV2011
Occupational Exposure Limit-INDIAtime-weighted average 50 ppm (55 mg/m3), short term exposure limit 400 ppm (440 mg/m3), JAN1993
Occupational Exposure Limit-JAPANOccupational Exposure Limit 50 ppm (57 mg/m3), MAY2012
Occupational Exposure Limit-KOREAtime-weighted average 50 ppm (55 mg/m3), short term exposure limit 400 ppm (440 mg/m3), 2006
Occupational Exposure Limit-MEXICOtime-weighted average 50 ppm (55 mg/m3);short term exposure limit 400 ppm (400 mg/m3), 2004
Occupational Exposure Limit-NEW ZEALANDshort term exposure limit 200 ppm (15 min), JAN2002
Occupational Exposure Limit-NEW ZEALANDshort term exposure limit 100 ppm (30 min), JAN2002
Occupational Exposure Limit-NEW ZEALANDshort term exposure limit 50 ppm (60 min), JAN2002
Occupational Exposure Limit-NORWAYtime-weighted average 35 ppm (40 mg/m3), JAN1999
Occupational Exposure Limit-PERUtime-weighted average 25 ppm (29 mg/m3), JUL2005
Occupational Exposure Limit-POLANDMAC(time-weighted average) 30 mg/m3, MAC(short term exposure limit) 180 mg/m3, JAN1999
Occupational Exposure Limit-RUSSIAshort term exposure limit 200 mg/m3 (15M), JUN2003
Occupational Exposure Limit-RUSSIAshort term exposure limit 100 mg/m3 (30M), JUN2003
Occupational Exposure Limit-RUSSIAshort term exposure limit 50 mg/m3 (1H), JUN2003
Occupational Exposure Limit-RUSSIAshort term exposure limit 20 mg/m3, JUN2003
Occupational Exposure Limit-SWEDENtime-weighted average 35 ppm (40 mg/m3);short term exposure limit 100 ppm (120 mg/m3), JUN2005
Occupational Exposure Limit-SWITZERLANDceiling concentration 30 ppm (35 mg/m3), JAN2011
Occupational Exposure Limit-THAILANDtime-weighted average 50 ppm (55 mg/m3), JAN1993
Occupational Exposure Limit-THE NETHERLANDSMAC-TGG 29 mg/m3, 2003
Occupational Exposure Limit-THE PHILIPPINEStime-weighted average 50 ppm (55 mg/m3), JAN1993
Occupational Exposure Limit-TURKEYtime-weighted average 50 ppm (55 mg/m3), JAN1993
Occupational Exposure Limit-UNITED KINGDOMtime-weighted average 30 ppm (35 mg/m3);short term exposure limit 200 ppm (232 mg/m3), OCT2007
Occupational Safety and Health Administration (OSHA) Permissible Exposure Limit (Construction)8H time-weighted average 50 ppm (55 mg/m3)CFRGBR 29,1926.55,1994
Occupational Safety and Health Administration (OSHA) Permissible Exposure Limit (Federal Contractors)8H time-weighted average 50 ppm (55 mg/m3)CFRGBR 41,50-204.50,1994
Occupational Safety and Health Administration (OSHA) Permissible Exposure Limit (General Industry)8H time-weighted average 50 ppm (55 mg/m3)CFRGBR 29,1910.1000,1994
Occupational Safety and Health Administration (OSHA) Permissible Exposure Limit (Shipyards)8H time-weighted average 50 ppm (55 mg/m3)CFRGBR 29,1915.1000,1993

NIOSH Documentation and Surveillance

OrganizationStandardReference
National Institute for Occupational Safety and Health (NIOSH) Recommended Exposure Level TO CARBON MONOXIDE-air8H time-weighted average 35 ppm;ceiling concentration 200 ppmNIOSH* DHHS #92-100,1992
National Occupational Exposure Survey 1983Hazard Code 17460; Number of Industries 24; Total Number of Facilities 1950; Number of Occupations 52; Total Number of Employees Exposed 68434; Total Number of Female Employees Exposed 7860
National Occupational Hazard Survey 1974Hazard Code 17460; Number of Industries 43; Total Number of Facilities 2593; Number of Occupations 68; Total Number of Employees Exposed 32958

Status in Federal Agencies

OrganizationReference
EPA TSCA Section 8(b) CHEMICAL INVENTORY
EPA TSCA Section 8(d) unpublished health/safety studies
EPA TSCA TEST SUBMISSION (TSCATS) DATA BASE, JANUARY 2001
NIOSH Analytical Method, 1996: Carbon monoxide, 6604
OSHA ANALYTICAL METHOD #ID209
OSHA ANALYTICAL METHOD #ID210
Page last reviewed: November 16, 2018