| Agent Name |
Carbon monoxide |
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| CAS Number |
630-08-0 |
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| Formula |
C-O |
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| Major Category |
Toxic Gases & Vapors |
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| Synonyms |
Carbon oxide; Flue gas; Monoxide; [NIOSH] |
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| Category |
Chemical Asphyxiants |
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| Description |
Colorless, odorless gas. [Note: Shipped as a nonliquefied or liquefied compressed gas.] [NIOSH] |
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| Sources/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] |
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| Comments |
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] Possible frostbite from contact with liquid; [NIOSH] See the Diseases, "Parkinsonism" and "Asphyxiation, chemical." |
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| Reference Link |
Carbon monoxide poisoning and death after the use of explosives in a sewer construction project |
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| Exposure Assessment |
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| BEI |
Carboxyhemoglobin in blood = 3.5% of hemoglobin at end of shift; carbon monoxide in end-exhaled air = 20 ppm at end of shift; |
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| Skin Designation (ACGIH) |
No |
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| TIH |
Yes |
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| TLV (ACGIH) |
25 ppm |
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| PEL (OSHA) |
50 ppm |
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| MAK |
30 ppm |
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| IDLH (NIOSH) |
1200 ppm |
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| Excerpts from Documentation for IDLHs |
Other human data: It has been stated that a 1�hour exposure to 1,000 to 1,200 ppm would cause unpleasant but no dangerous symptoms, but that 1,500 to 2,000 ppm might be a dangerous concentration after 1 hour [Henderson et al. 1921a, 1921b]. In general, a carboxyhemoglobin (COHb) level of 10�20% will only cause slight headaches [NIOSH 1972] and a COHb of 11�13% will have no effect on hand and foot reaction time, hand steadiness, or coordination [Stewart and Peterson 1970]. At a COHb of 35%, manual dexterity is impaired [Stewart 1975]. At 40% COHb, mental confusion, added to increasing incoordination, precludes driving an automobile [Stewart 1975]. A 30�minute exposure to 1,200 ppm will produce a COHb of 10�13% [NIOSH 1972]. |
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| Lethal Concentration |
LC50 (rats) = 1,807 ppm/4H |
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| Half Life |
Elimination 1/2 life: 5-6 hours (shortened by administration of oxygen); [TDR, p. 283] |
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| Flammability (NFPA) |
4: burns readily |
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| Adverse Effects |
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| Neurotoxin |
Parkinson's Syndrome |
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| Reproductive Toxin |
Yes |
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| Other Poison |
Chemical Asphyxiant |
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| Links to Other NLM Databases |
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| Health Studies |
Human Health Effects from Hazardous Substances Data Bank: CARBON MONOXIDE
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