1. OSHA Occupational Chemical Database
  2. HYDROGEN CYANIDE
Label abbreviations descriptions

HYDROGEN CYANIDE†

Chemical Identification
Chemical Identification
CAS # 74-90-8
Formula

CHN
Synonyms

formonitrile; hydrocyanic acid; prussic acid
Physical Properties
Physical Properties
Physical description Colorless or pale-blue liquid or gas (above 78°F) with a bitter, almond-like odor.
Boiling point 78°F (96%) Molecular weight 27
Freezing point/melting point 7°F (96%) Vapor pressure 630 mmHg
Flash point 0°F (96%) Vapor density
Specific gravity 0.69 Ionization potential 13.60 eV
Lower explosive limit (LEL) 5.6% Upper explosive limit (UEL) 40%
NFPA health rating 4 NFPA fire rating 4
NFPA reactivity rating 1 NFPA special instruction
Vapor hazard ratio (VHR)
Historical exceedance percentage
Target organs
Monitoring Methods Used by OSHA
Monitoring Methods Used by OSHA
Analyte code (IMIS no.) 1440
Sampling group
Sampler/Sampling media SKC ULTRA II Hydrogen Cyanide Passive Sampler, Soda Lime, 600 mg [SKC 590-400]
Sampling time*
 

240 min
Sampling volume (TWA)*
 

6.816 L
Sampling flow rate (TWA)*
 

0.0284 L/min
Sampling volume (STEL/Peak/C)*
 

 
Sampling flow rate (STEL/Peak/C)*
 

 
Analytical method instruments IC
Method reference OSHA 1015 (fully validated)
Notes
 

If hydrogen sulfide is present at its PEL, there could be an interference and a thiocyanate peak will be seen at the same IC conditions ran for cyanide.
Special requirements
 

 

* All sampling instructions above are recommended guidelines for OSHA Compliance Safety and Health Officers (CSHOs), please see the corresponding OSHA method reference for complete details.

Wipe Method
Wipe Method
Sampler/Sampling media
 

 
Bulk Method
Bulk Method
 

Available
On-Site Screening Techniques
On-Site Screening Techniques
Device Detector tube CMS Chip
Model/Type Dräger - Cyanide 2/a, 6728791 Hydrocyanic acid, 2-50 ppm range
Sampling information
(see manufacturer instructions) 		10 strokes, approx 1-15 mg/m³ range, uncertainty 33-49%
Exposure Limits
Exposure Limits
OSHA PEL
8-hour TWA
(ST) STEL
(C) Ceiling
Peak
NIOSH REL
Up to 10-hour TWA
(ST) STEL
(C) Ceiling
ACGIH TLV©
8-hour TWA
(ST) STEL
(C) Ceiling
CAL/OSHA PEL
8-hour TWA
(ST) STEL
(C) Ceiling
Peak
PEL-TWA
 

10 ppm (11 mg/m³)

 REL-TWA
 

 

 TLV-TWA
 

 

 PEL-TWA
 

 
PEL-STEL
 

 

 REL-STEL
 

4.7 ppm (5 mg/m³)

 TLV-STEL
 

 

 PEL-STEL
 

 
PEL-C
 

 

 REL-C
 

 

 TLV-C
 

4.7 ppm [1991]

 PEL-C
 

4.7 ppm (5 mg/m³)
Skin notation
 

Y

 Skin notation
 

Y

 Skin notation
 

Y

 Skin notation
 

Y
Notes:
 

See 29 CFR 1910.1000 Table Z-1.

 Notes:
 

 

 Notes:
 

 

 Notes:
 

 
Health factors:  See NIH-NLM PubChem. IDLH
 

50 ppm
Carcinogenic classifications: EPA-II Notes:
 

 
AIHA emergency response planning guidelines - ERPG-1/ERPG-2/ERPG-3:
 

--/10 ppm/25 ppm
Additional Resources and Literature References
Additional Resources and Literature References

NOAA: CAMEO Chemicals - Hydrocyanic acid, aqueous solution, with not more than 20% hydrogen cyanide

NIOSH: Pocket Guide to Chemical Hazards - Hydrogen cyanide

Literature References

 
  • ACGIH: Documentation of the Threshold Limit Values (TLVs) and Biological Exposure Indices (BEIs) - Hydrogen cyanide and cyanide salts, as CN. See annual publication for most recent information.
  • Agency for Toxic Substances and Disease Registry (ATSDR): Toxicological Profile for Cyanide (Update). PHS, U.S. DHHS, Atlanta, GA, 1997.
  • U.S. EPA Technology Transfer Network Air Toxics Website: Cyanide Compounds.
  • Albin, R.L.: Basal ganglia neurotoxins. Neurol. Clin. 18(3): 665-680, 2000

Last Updated Date : 12/31/2020