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Hydrogen cyanide
May 1994
Immediately Dangerous to Life or Health Concentrations (IDLH)
CAS number: 74–90–8
NIOSH REL: 4.7 ppm (5 mg/m3) STEL [skin]
Current OSHA PEL: 10 ppm (11 mg/m3) TWA [skin]
1989 OSHA PEL: 4.7 ppm (5 mg/m3) STEL [skin]
1993-1994 ACGIH TLV: 10 ppm (11 mg/m3) CEILING [skin]
Description of Substance: Colorless or pale-blue liquid or gas (above 78°F) with a bitter, almond-like odor.
LEL:. . 5.6% (10% LEL, 5,600 ppm)
Original (SCP) IDLH: 50 ppm
Basis for original (SCP) IDLH: The chosen IDLH is based on the statements by Patty [1963] that 45 to 54 ppm is “tolerated by man for 0.5 to 1 hour without immediate or late effects; 110 to 135 ppm, however, may be fatal after 0.5 to 1 hour or later, or dangerous to life [Flury and Zernik 1931; Dudley et al. 1942].”
Short-term exposure guidelines: None developed
ACUTE TOXICITY DATA:
Lethal concentration data:
| Species | Reference | LC50(ppm) | LCLo(ppm) | Time | Adjusted 0.5-hrLC (CF*) | Derived value |
|---|---|---|---|---|---|---|
| Mammal | AAPCO 1966 | —– | 200 | 5 min | 103 ppm (0.52) | 10 ppm |
| Mamma | Arena 1970 | —– | 36 | 2 hr | 60 ppm (1.67) | 6.0 ppm |
| Human | Dudley et al. 1942 | —– | 107 | 10 min | 71 ppm (0.67) | 7.1 ppm |
| Rat | Dudley et al. 1942 | 503 | —– | 5 min | 259 ppm (0.52) | 26 ppm |
| Mouse | Dudley et al. 1942 | 323 | —– | 5 min | 166 ppm (0.52) | 17 ppm |
| Rabbit | Gates et al. 1946 | —– | 759 | 1 min | 216 ppm (0.28) | 22 ppm |
| Cat | Gates et al. 1946 | —– | 759 | 1 min | 216 ppm (0.28) | 22 ppm |
| Rat | Hartzell et al. 1985 | 275 | —– | 15 min | 213 ppm (0.77) | 21 ppm |
| Rat | Hartzell et al. 1985 | 170 | —– | 30 min | 170 ppm (1.0) | 17 ppm |
| Human | Izmerov et al. 1982 | —– | 357 | 2 min | 131 ppm (0.37) | 13 ppm |
| Rat | Levin et al. 1987 | 160 | —– | 30 min | 160 ppm (1.0) | 16 ppm |
| Rat | Vernot et al. 1977 | 323 | —– | 5 min | 166 ppm (0.52) | 17 ppm |
| Human | WHO 1970 | —– | 179 | 1 hr | 231 ppm (0.69) | 23 ppm |
*Note: Conversion factor (CF) was determined with “n” = 2.7 [ten Berge et al. 1986].
Other animal data: The median effective concentrations to produce incapacitation (EC50s) in rats have been determined to be 139 ppm and 115 ppm in 15 and 30 minutes, respectively [Hartzell et al. 1985].
Other human data: It has been reported that 45 to 54 ppm can be tolerated for 0.5 to 1 hour without immediate or delayed effects while 110 to 135 ppm may be fatal after 0.5 to 1 hour or later, or dangerous to life [Flury and Zernik 1931].
| Revised IDLH: 50 ppm [Unchanged]Basis for revised IDLH: Based on acute inhalation toxicity data in humans [Flury and Zernik 1931], the IDLH for hydrogen cyanide (50 ppm) is not being revised at this time. |
REFERENCES:
1. AAPCO [1966]. Pesticide chemicals official compendium. Topeka, KS: Association of the American Pesticide Control Officials, Inc., p. 596.
2. Arena JM [1970]. Poisoning; toxicology, symptoms, treatments. 2nd ed. Springfield, IL: C.C. Thomas, 2:73.
3. Dudley HC, Sweeney TR, Miller JW [1942]. Toxicology of acrylonitrile (vinyl cyanide). II. Studies of effects of daily inhalation. J Ind Hyg Toxicol 23:255-258.
4. Flury F, Zernik F [1931]. Schädliche gase dämpfe, nebel, rauch- und staubarten. Berlin, Germany: Verlag von Julius Springer, p. 404 (in German).
5. Gates M, Williams J, Zapp JA [1946]. Arsenicals. In: Summary technical report of Division 9, NRDC. Vol. 1. Chemical warfare agents, and related chemical problems. Part I. Washington, DC: Office of Scientific Research and Development, National Defense Research Committee, pp. 83-114.
6. Hartzell GE, Priest DN, Switzer WG [1985]. Modeling of toxicological effects of fire gases. II. Mathematical modeling of intoxication of rats by combined carbon monoxide and hydrogen cyanide. J Fire Sci 3:115-128.
7. Izmerov NF, Sanotsky IV, Sidorov KK [1982]. Toxicometric parameters of industrial toxic chemicals under single exposure. Moscow, Russia: Centre of International Projects, GKNT, p. 75.
8. Levin BC, Paabo M, Gurman JL, Harris SE [1987]. Effects of exposure to single or multiple combinations of the predominant toxic gases and low oxygen atmospheres produced in fires. Fundam Appl Toxicol 9:236-250.
9. Patty FA, ed. [1963]. Industrial hygiene and toxicology. 2nd rev. ed. Vol. II. Toxicology. New York, NY: Interscience Publishers, Inc., p. 1998.
10. ten Berge WF, Zwart A, Appelman LM [1986]. Concentration-time mortality response relationship of irritant and systematically acting vapours and gases. J Haz Mat 13:301-309.
11. Vernot EH, MacEwen JD, Haun CC, Kinkead ER [1977]. Acute toxicity and skin corrosion data for some organic and inorganic compounds and aqueous solutions. Toxicol Appl Pharmacol 42:417-423.
12. WHO [1970]. Technical report series 30. Geneva, Switzerland: World Health Organization.