HYDROGEN CYANIDE, ANHYDROUS, STABILIZED (ABSORBED)

Diamond	Hazard	Value	Description
4 4 1	Health	4	Can be lethal.
	Flammability	4	Burns readily. Rapidly or completely vaporizes at atmospheric pressure and normal ambient temperature.
	Instability	1	Normally stable but can become unstable at elevated temperatures and pressures.
	Special

A clear colorless liquid with a faint odor of bitter almonds that is absorbed in a porous inert material. Absorption slows evolution of vapors. Vapors slightly lighter than air. Deadly poison by all routes (absorption through skin of liquid, inhalation of vapors, etc). Prolonged exposure of closed containers to heat may cause violent rupture and rocketing.

Rate of onset: Immediate

Persistence: Minutes

Odor threshold: 1-5 ppm

Source/use/other hazard: War gas, pesticide, Herbicide; other industries; Weak acid except in water or mucous membranes - then corrosive/training.

• Highly Flammable
• Polymerizable

Highly flammable but absorption can prevent evolution of enough vapors to ignite. Flame may easily travel back to source of leak. Vapors forms explosive mixtures with air. Soluble in water (exception of absorbing material).

Excerpt from 152 [Substances - Toxic (Combustible)]:

Combustible material: may burn but does not ignite readily. Containers may explode when heated. Runoff may pollute waterways. Substance may be transported in a molten form. (ERG, 2020)

Excerpt from 152 [Substances - Toxic (Combustible)]:

Highly toxic, may be fatal if inhaled, ingested or absorbed through skin. Contact with molten substance may cause severe burns to skin and eyes. Avoid any skin contact. Effects of contact or inhalation may be delayed. Fire may produce irritating, corrosive and/or toxic gases. Runoff from fire control or dilution water may be corrosive and/or toxic and cause environmental contamination. (ERG, 2020)

HYDROGEN CYANIDE, ANHYDROUS reacts as an oxidizing agent and as a weak acid. Absorption moderates its reactivity. Presents an explosion hazard when heated or exposed to oxidizing agents. Reacts violently with acetaldehyde. May polymerize explosively at elevated temperature. May polymerize in the presence of traces of alkali [Wohler, L. et al., Chem. Ztg., 1926, 50, p. 761, 781]. During the preparation of imidoester hydrochlorides, hydrogen chloride was rapidly passed over an alcoholic solution of hydrogen cyanide. An explosion ensued, even with cooling of the process [J. Org. Chem., 1955, 20, 1573].

• Cyanides, Inorganic
• Acids, Weak
• Polymerizable Compounds

Use caution: Liquids with this reactive group classification have been known to react with the absorbents listed below.

• Mineral-Based & Clay-Based Absorbents
• Dirt/Earth

Excerpt from 152 [Substances - Toxic (Combustible)]:

IMMEDIATE PRECAUTIONARY MEASURE: Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters (75 feet) for solids.

SPILL: See ERG Table 1 - Initial Isolation and Protective Action Distances on the UN/NA 1614 datasheet.

FIRE: If tank, rail car or tank truck is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions. (ERG, 2020)

Excerpt from 152 [Substances - Toxic (Combustible)]:

SMALL FIRE: Dry chemical, CO2 or water spray.

LARGE FIRE: Water spray, fog or regular foam. If it can be done safely, move undamaged containers away from the area around the fire. Dike runoff from fire control for later disposal. Avoid aiming straight or solid streams directly onto the product.

FIRE INVOLVING TANKS OR CAR/TRAILER LOADS: Fight fire from maximum distance or use unmanned master stream devices or monitor nozzles. Do not get water inside containers. Cool containers with flooding quantities of water until well after fire is out. Withdraw immediately in case of rising sound from venting safety devices or discoloration of tank. ALWAYS stay away from tanks engulfed in fire. For massive fire, use unmanned master stream devices or monitor nozzles; if this is impossible, withdraw from area and let fire burn. (ERG, 2020)

Excerpt from 152 [Substances - Toxic (Combustible)]:

ELIMINATE all ignition sources (no smoking, flares, sparks or flames) from immediate area. Do not touch damaged containers or spilled material unless wearing appropriate protective clothing. Stop leak if you can do it without risk. Prevent entry into waterways, sewers, basements or confined areas. Cover with plastic sheet to prevent spreading. Absorb or cover with dry earth, sand or other non-combustible material and transfer to containers. DO NOT GET WATER INSIDE CONTAINERS. (ERG, 2020)

Excerpt from NIOSH Pocket Guide for Hydrogen cyanide:

Skin: PREVENT SKIN CONTACT - Wear appropriate personal protective clothing to prevent skin contact.

Eyes: PREVENT EYE CONTACT - Wear appropriate eye protection to prevent eye contact.

Wash skin: WHEN CONTAMINATED - The worker should immediately wash the skin when it becomes contaminated.

Remove: WHEN WET (FLAMMABLE) - Work clothing that becomes wet should be immediately removed due to its flammability hazard (i.e., for liquids with a flash point <100°F).

Change: No recommendation is made specifying the need for the worker to change clothing after the workshift.

Provide:
• EYEWASH - Eyewash fountains should be provided in areas where there is any possibility that workers could be exposed to the substances; this is irrespective of the recommendation involving the wearing of eye protection.
• QUICK DRENCH - Facilities for quickly drenching the body should be provided within the immediate work area for emergency use where there is a possibility of exposure. [Note: It is intended that these facilities provide a sufficient quantity or flow of water to quickly remove the substance from any body areas likely to be exposed. The actual determination of what constitutes an adequate quick drench facility depends on the specific circumstances. In certain instances, a deluge shower should be readily available, whereas in others, the availability of water from a sink or hose could be considered adequate.] (NIOSH, 2023)

Normalized Breakthrough Times (in Minutes)

Chemical	CAS Number	State	QS	QC	SL	C3	TF	TP	RC	TK	RF
Hydrogen cyanide (21°C, liquid)	74-90-8	Liquid							135	>480	135
Hydrogen cyanide (27°C, gaseous)	74-90-8	Vapor				30			>480	>480	>480

Special Warning from DuPont: Tychem® and Tyvek® fabrics should not be used around heat, flames, sparks or in potentially flammable or explosive environments. Only...

(DuPont, 2023)

Excerpt from NIOSH Pocket Guide for Hydrogen cyanide:

Eye: IRRIGATE IMMEDIATELY - If this chemical contacts the eyes, immediately wash (irrigate) the eyes with large amounts of water, occasionally lifting the lower and upper lids. Get medical attention immediately.

Skin: WATER FLUSH IMMEDIATELY - If this chemical contacts the skin, immediately flush the contaminated skin with water. If this chemical penetrates the clothing, immediately remove the clothing and flush the skin with water. Get medical attention promptly.

Breathing: RESPIRATORY SUPPORT - If a person breathes large amounts of this chemical, move the exposed person to fresh air at once. If breathing has stopped, perform artificial respiration. Keep the affected person warm and at rest. Get medical attention as soon as possible.

Swallow: MEDICAL ATTENTION IMMEDIATELY - If this chemical has been swallowed, get medical attention immediately. (NIOSH, 2023)

• CARBON HYDRIDE NITRIDE (CHN)
• EVERCYN
• FORMIC ANAMMONIDE
• FORMONITRILE
• HYDROCYANIC ACID
• HYDROGEN CYANIDE
• HYDROGEN CYANIDE (HYDROCYANIC ACID)
• HYDROGEN CYANIDE, ANHYDROUS, STABILIZED (ABSORBED)
• HYDROGEN CYANIDE, STABILIZED (ABSORBED)
• HYDROGEN CYANIDE, [ABSORBED]
• PRUSSIC ACID