Chemical of the Week Part 2 - Hydrogen Cyanide

Hazard Profile

Chemical Name and Pseudonyms

Hydrogen Cyanide, Formonitrile, Hydrocyanic Acid, Prussic Acid, Hydrocyanic Acid

UN Number

1051 (anhydrous or solution >20%) 1613  (solution <20%)

Chemical Formula

HCN

Hazards

Toxic, flammable

PPE Considerations

Vapor protective garment with SCBA if below LEL, avoid contact.

Fire Fighting Considerations

Unstable HCN may explosively polymerize.  Let small fires burn unless able to immediately stop leak.  Extinguish with CO2, dry chemical or ATC-AFFF.  Keep tanks cool with water streams. 

Decontamination

Soap and water with adequate ventilation, forced ventilation for gas only contamination, remove contaminated garments

Detection and Monitoring

Colormetric, electrochemical sensors, 4/5-gas meter, IP – 13.6 eV

Chemical and Physical Properties

Physical State

Colorless or pale-blue liquid or gas (above 78°F) with a bitter, almond-like odor

Vapor Pressure

630 mm/Hg

Boiling Point

78^oF

Vapor Density

.941

Specific Gravity

.69

Miscibility

Soluble

Flash Point

0^oF

LEL/UEL

5.6-40%

Autoignition Temp

1000^oF

Toxicity

IDLH

50 ppm

PEL/REL/STEL

10/4.7/4.7 ppm

LC50

160-501 ppm

pH

N/A (may form acid in solution)

Radioactive (Yes/No)

No

Medical

Toxicological Considerations

Toxic by all routes. 

Signs/Symptoms of Exposure

Cardiac, respiratory, CNS

Medical Treatment

Treat symptomatically and administer antidote

Other Information

Toxic by all routes, extreme flammability hazard, may polymerize, reactive with following absorbents: Mineral-Based & Clay-Based Absorbents, Dirt/Earth

AEGL

Chemical Structure