| Agent Name |
CYANIDES |
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| Alternative Name |
CLASS |
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| Major Category |
Toxic Gases & Vapors |
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| Synonyms |
See: Hydrogen cyanide, Sodium cyanide, Potassium cyanide and Calcium cyanide |
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| Category |
Chemical Asphyxiants |
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| Description |
Salts of cyanide include sodium, ammonium, barium, cadmium, calcium, copper, gold, lead, mercury, potassium, silver, and zinc; |
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| Sources/Uses |
Used in electroplating, silver and gold extraction, metal cleaning, metal nitriding, ship fumigating, mining processes, cement stabilizing, photo developing, and organic synthesis; Used in the past to fumigate fruit trees, railroad cars, warehouses, rabbit and rat burrows, and termite nests; In tropical countries where the potato-like tubers of the cassava plant are grown, cyanide poisonings due to ingestion of the cassava root have been reported. [ATSDR ToxProfiles] |
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| Comments |
A fatal inhalation dose of hydrogen cyanide is 600 to 700 ppm for 5 minutes or 200 ppm for 30 minutes. In victims overcome by smoke inhalation, hypoxia from carbon monoxide is initially indistinguishable from that caused by cyanide. Smokers have elevated whole blood cyanide levels up to 0.4 ug/ml. In poisoning cases, victims are agitated at levels above 1.0 ug/ml and comatose at levels above 2.5 ug/ml. Acrylonitrile, acetonitrile, and other aliphatic nitriles can cause cyanide poisoning after absorption and hepatic transformation. [ATSDR Case Studies # 15] "Symptoms of cyanide toxicity can occur within seconds of inhalation of hydrogen cyanide or within minutes of ingestion of cyanide salts. Onset may be delayed up to 12 h after ingestion of cyanogenic glycosides, nitriles, or thiocyanates." [INCHEM: CICAD 61] Urine thiocyanate levels are <0.11 mg/24 h without occupational exposure. The no-adverse-effect-level is 6.5 mg/24h. Smokers have higher levels. [LaDou, p. 633] In nitroprusside poisoning cases, the half-life of thiocyanate is 2.7 days (normal renal function). [Ford, p. 410] Thiocyanate levels correlate with thiocyanate toxicity, not with degree of cyanide poisoning. Toxicity occurs when thiocyanate levels exceed 100 mg/L. [Haddad, p. 985] Chronic exposure to cyanide causes tobacco amblyopia (smoking) and tropical ataxic neuropathy (eating improperly processed cassava). Both conditions are associated with low B12 levels. Thiocyanate can competitively inhibit the entry of iodide into the thyroid gland and cause hypothyroidism and goiters. [Goldfrank, p. 1715] |
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| Exposure Assessment |
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| Skin Designation (ACGIH) |
Yes |
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| Ceiling (ACGIH) |
5 mg/m3, as CN(calcium,hydrogen,sodium,and potassium cyanide) |
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| PEL (OSHA) |
5 mg/m3,as CN(calcium,sodium,and potassium cyanide), 11 mg/m3(hydrogen cyanide) |
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| MAK |
2 mg/m3,as CN,inhalable fraction(calcium cyanide), 2.1 mg/m3(hydrogen cyanide), 5 mg/kg, as CN, inhalable fraction(potassium cyanide), 3.8 mg/m3, as CN, inhalable fraction(sodium cyanide) |
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| IDLH (NIOSH) |
25 mg/m3, as CN(sodium and potassium cyanide), 50 ppm(hydrogen cyanide) |
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| Excerpts from Documentation for IDLHs |
Basis for original (SCP) IDLH: No useful acute inhalation toxicity data are available on which to base the IDLH for cyanides. For this draft technical standard, therefore, the chosen IDLH is based on an analogy with hydrogen cyanide. According to ACGIH [1971], Patty [1963] reported that hydrogen cyanide at 110 to 135 ppm (120 to 150 mg/m3) might be fatal to man after 0.5 to 1 hour or later, or dangerous to life; 45 to 54 ppm (50 to 60 mg/m3) could be tolerated for 0.5 to 1 hour without immediate or late effects [Flury and Zernik 1931; Dudley et al. 1942]. . . .
Human data: Absorption of the alkali cyanides in amounts as low as 50 to 100 mg from a single, instantaneous dose may be followed by immediate collapse and cessation of respiration [Clayton and Clayton 1982]. It has been stated that although the fatal oral dose will vary considerably, depending on whether or not food is present in the stomach, it is probably in the order of 1 to 2 mg/kg [Clayton and Clayton]. [Note: An oral dose of 50 to 100 mg or 1 to 2 mg/kg is equivalent to a 70�kg worker being exposed to about 50 mg/m3 (as CN) for 30 minutes, assuming a breathing rate of 50 liters per minute and 100% absorption.] |
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| Half Life |
Whole body: 19 hours; [TDR, p. 422] |
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| Reference Link |
ATSDR - ToxFAQs - Cyanide |
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| Adverse Effects |
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| Other Poison |
Chemical Asphyxiant |
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| Links to Other NLM Databases |
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