HYDROCYANIC ACID, AQUEOUS SOLUTION, WITH NOT MORE THAN 20% HYDROGEN CYANIDE
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The
Chemical Identifier fields
include common identification numbers, the
NFPA diamond
U.S. Department of Transportation hazard labels, and a general
description of the chemical. The information in CAMEO Chemicals comes
from a variety of
data sources.
| CAS Number | UN/NA Number |
|---|---|
|
|
| DOT Hazard Label | USCG CHRIS Code |
|
none |
| NIOSH Pocket Guide | International Chem Safety Card |
Hydrogen cyanide
|
NFPA 704
| Diamond | Hazard | Value | Description | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
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
|
(NFPA, 2010)
General Description
Clear colorless aqueous solution of a gas. Has a faint odor of almonds. Can evolve hydrogen cyanide gas, which is (barely) lighter than air. Flame can flash back to the source of a gas leak very easily. Lethal doses of gas may be inhaled. Lethal doses of cyanide can be absorbed from the solution through the skin.
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The
Hazard fields
include
special hazard alerts
air and water
reactions, fire hazards, health hazards, a reactivity profile, and
details about
reactive groups assignments
and
potentially incompatible absorbents.
The information in CAMEO Chemicals comes from a variety of
data sources.
Reactivity Alerts
- Polymerizable
Air & Water Reactions
No rapid reaction with air. No rapid reaction with water.
Fire Hazard
Excerpt from ERG Guide 154 [Substances - Toxic and/or Corrosive (Non-Combustible)]:
Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive and/or toxic fumes. Some are oxidizers and may ignite combustibles (wood, paper, oil, clothing, etc.). Contact with metals may evolve flammable hydrogen gas. Containers may explode when heated. For electric vehicles or equipment, ERG Guide 147 (lithium ion batteries) or ERG Guide 138 (sodium batteries) should also be consulted. (ERG, 2020)
Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive and/or toxic fumes. Some are oxidizers and may ignite combustibles (wood, paper, oil, clothing, etc.). Contact with metals may evolve flammable hydrogen gas. Containers may explode when heated. For electric vehicles or equipment, ERG Guide 147 (lithium ion batteries) or ERG Guide 138 (sodium batteries) should also be consulted. (ERG, 2020)
Health Hazard
Excerpt from ERG Guide 154 [Substances - Toxic and/or Corrosive (Non-Combustible)]:
TOXIC; inhalation, ingestion or skin contact with material may cause severe injury or death. 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)
TOXIC; inhalation, ingestion or skin contact with material may cause severe injury or death. 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)
Reactivity Profile
HYDROCYANIC ACID, AQUEOUS SOLUTION, WITH NOT MORE THAN 20% HYDROGEN CYANIDE reacts with acid to evolve hydrogen cyanide, a very poisonous colorless gas smelling of bitter almonds which is a deadly human poison by all routes. Carbon dioxide from the air is sufficiently acidic to liberate HCN from aqueous solutions of hydrocyanic acid [Lewis]. The solution also can evolve gaseous hydrogen cyanide when heated. Inhalation of gaseous HCN is quickly fatal by respiratory arrest. The gas forms flammable or explosive mixtures with air (may be difficult to ignite at lower concentrations). It presents an explosion hazard when heated with or exposed to other oxidizing agents and may polymerize explosively at elevated temperature (50-60°C) or in the presence of traces of alkali [Wohler, L. et al., Chem. Ztg., 1926, 50, p. 761, 781]. It reacts violently with acetaldehyde. During the preparation of imidoester hydrochlorides, hydrogen chloride was rapidly passed over an alcoholic solution of hydrogen cyanide. An explosion ensued, despite cooling of the process [J. Org. Chem., 1955, 20, 1573]. In the absence of a stabilizer (e.g. phosphoric acid) it may undergo explosively rapid spontaneous (autocatalytic) polymerization leading to a fire. The reaction is autocatalytic because of ammonia formation [Bond, J., Loss Prev. Bull., 1991, 101, p.3].
Belongs to the Following Reactive Group(s)
Potentially Incompatible Absorbents
Use caution: Liquids with this reactive group classification have been known to react with the absorbents listed below. More info about absorbents, including situations to watch out for...
- Mineral-Based & Clay-Based Absorbents
- Dirt/Earth
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The
Response Recommendation fields
include isolation and evacuation distances, as well as recommendations for
firefighting, non-fire response, protective clothing, and first aid. The
information in CAMEO Chemicals comes from a variety of
data sources.
Isolation and Evacuation
Excerpt from ERG Guide 154 [Substances - Toxic and/or Corrosive (Non-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 1613 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)
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 1613 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)
Firefighting
Excerpt from ERG Guide 154 [Substances - Toxic and/or Corrosive (Non-Combustible)]:
SMALL FIRE: Dry chemical, CO2 or water spray.
LARGE FIRE: Dry chemical, CO2, alcohol-resistant foam or water spray. If it can be done safely, move undamaged containers away from the area around the fire. Dike runoff from fire control for later disposal.
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. (ERG, 2020)
SMALL FIRE: Dry chemical, CO2 or water spray.
LARGE FIRE: Dry chemical, CO2, alcohol-resistant foam or water spray. If it can be done safely, move undamaged containers away from the area around the fire. Dike runoff from fire control for later disposal.
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. (ERG, 2020)
Non-Fire Response
Excerpt from ERG Guide 154 [Substances - Toxic and/or Corrosive (Non-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. Absorb or cover with dry earth, sand or other non-combustible material and transfer to containers. DO NOT GET WATER INSIDE CONTAINERS. (ERG, 2020)
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. Absorb or cover with dry earth, sand or other non-combustible material and transfer to containers. DO NOT GET WATER INSIDE CONTAINERS. (ERG, 2020)
Protective Clothing
Excerpt from ERG Guide 154 [Substances - Toxic and/or Corrosive (Non-Combustible)]:
Wear positive pressure self-contained breathing apparatus (SCBA). Wear chemical protective clothing that is specifically recommended by the manufacturer when there is NO RISK OF FIRE. Structural firefighters' protective clothing provides thermal protection but only limited chemical protection. (ERG, 2020)
Wear positive pressure self-contained breathing apparatus (SCBA). Wear chemical protective clothing that is specifically recommended by the manufacturer when there is NO RISK OF FIRE. Structural firefighters' protective clothing provides thermal protection but only limited chemical protection. (ERG, 2020)
DuPont Tychem® Suit Fabrics
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Tychem® Fabric Legend
| QS = Tychem 2000 SFR |
| QC = Tychem 2000 |
| SL = Tychem 4000 |
| C3 = Tychem 5000 |
| TF = Tychem 6000 |
| TP = Tychem 6000 FR |
| RC = Tychem RESPONDER® CSM |
| TK = Tychem 10000 |
| RF = Tychem 10000 FR |
Testing Details
The fabric permeation data was generated for DuPont by a third party
laboratory. Permeation data for industrial chemicals is obtained per
ASTM F739. Normalized breakthrough times (the time at which the
permeation rate exceeds 0.1 μg/cm2/min) are reported in minutes. All
chemicals have been tested between approximately 20°C and 27°C unless
otherwise stated. All chemicals have been tested at a concentration of
greater than 95% unless otherwise stated.
Chemical warfare agents (Lewisite, Sarin, Soman, Sulfur Mustard, Tabun
and VX Nerve Agent) have been tested at 22°C and 50% relative humidity
per military standard MIL-STD-282. "Breakthrough time" for chemical
warfare agents is defined as the time when the cumulative mass which
permeated through the fabric exceeds the limit in MIL-STD-282 [either
1.25 or 4.0 μg/cm2].
A Caution from DuPont
This information is based upon technical data that DuPont believes to
be reliable on the date issued. It is subject to revision as additional
knowledge and experience are gained. The information reflects
laboratory performance of fabrics, not complete garments, under
controlled conditions. It is intended for informational use by persons
having technical skill for evaluation under their specific end-use
conditions, at their own discretion and risk. It is the user's
responsibility to determine the level of toxicity and the proper
personal protective equipment needed. Anyone intending to use this
information should first verify that the garment selected is suitable
for the intended use. In many cases, seams and closures have shorter
breakthrough times and higher permeation rates than the fabric. If
fabric becomes torn,abraded or punctured, or if seams or closures fail,
or if attached gloves, visors, etc. are damaged, end user should
discontinue use of garment to avoid potential exposure to chemical.
Since conditions of use are outside our control, DuPont makes no
warranties, express or implied, including, without limitation, no
warranties of merchantability or fitness for a particular use and
assume no liability in connection with any use of this information.
This information is not intended as a license to operate under or a
recommendation to infringe any patent, trademark or technical
information of DuPont or others covering any material or its use.
| 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 |
> indicates greater than.
Special Warning from DuPont: Tychem® and Tyvek® fabrics should not be used around heat, flames, sparks or in potentially flammable or explosive environments. Only...
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...Tychem® ThermoPro, Tychem® Reflector® and Tychem® TK styles 600T/601T
(with aluminized outer suit) garments are designed and tested to help
reduce burn injury during escape from a flash fire. Users of Tychem®
ThermoPro, Tychem® Reflector® and Tychem® TK styles 600T/601T (with
aluminized outer suit) garments should not knowingly enter an explosive
environment. Tychem® garments with attached socks must be worn inside
protective outer footwear and are not suitable as outer footwear. These
attached socks do not have adequate durability or slip resistance to be
worn as the outer foot covering.
(DuPont, 2023)
First Aid
Excerpt from ERG Guide 154 [Substances - Toxic and/or Corrosive (Non-Combustible)]:
Call 911 or emergency medical service. Ensure that medical personnel are aware of the material(s) involved and take precautions to protect themselves. Move victim to fresh air if it can be done safely. Give artificial respiration if victim is not breathing. Do not perform mouth-to-mouth resuscitation if victim ingested or inhaled the substance; wash face and mouth before giving artificial respiration. Use a pocket mask equipped with a one-way valve or other proper respiratory medical device. Administer oxygen if breathing is difficult. Remove and isolate contaminated clothing and shoes. In case of contact with substance, immediately flush skin or eyes with running water for at least 20 minutes. For minor skin contact, avoid spreading material on unaffected skin. Keep victim calm and warm. Effects of exposure (inhalation, ingestion or skin contact) to substance may be delayed. (ERG, 2020)
Call 911 or emergency medical service. Ensure that medical personnel are aware of the material(s) involved and take precautions to protect themselves. Move victim to fresh air if it can be done safely. Give artificial respiration if victim is not breathing. Do not perform mouth-to-mouth resuscitation if victim ingested or inhaled the substance; wash face and mouth before giving artificial respiration. Use a pocket mask equipped with a one-way valve or other proper respiratory medical device. Administer oxygen if breathing is difficult. Remove and isolate contaminated clothing and shoes. In case of contact with substance, immediately flush skin or eyes with running water for at least 20 minutes. For minor skin contact, avoid spreading material on unaffected skin. Keep victim calm and warm. Effects of exposure (inhalation, ingestion or skin contact) to substance may be delayed. (ERG, 2020)
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The
Physical Property fields
include properties such as vapor pressure and
boiling point, as well as explosive limits and
toxic exposure thresholds
The information in CAMEO Chemicals comes from a variety of
data sources.
Note: For Vapor Density and Specific Gravity, comparing the value to 1.0 can tell you if the chemical will likely sink/rise in air or sink/float in fresh water (respectively). Short phrases have been added to those values below as an aid. However, make sure to also consider the circumstances of a release. The Vapor Density comparisons are only valid when the gas escaping is at the same temperature as the surrounding air itself. If the chemical is escaping from a container where it was pressurized or refrigerated, it may first escape and behave as a heavy gas and sink in the air (even if it has a Vapor Density value less than 1). Also, the Specific Gravity comparisons are for fresh water (density 1.0 g/mL). If your spill is in salt water (density about 1.027 g/mL), you need to adjust the point of comparison. There are some chemicals that will sink in fresh water and float in salt water.
Note: For Vapor Density and Specific Gravity, comparing the value to 1.0 can tell you if the chemical will likely sink/rise in air or sink/float in fresh water (respectively). Short phrases have been added to those values below as an aid. However, make sure to also consider the circumstances of a release. The Vapor Density comparisons are only valid when the gas escaping is at the same temperature as the surrounding air itself. If the chemical is escaping from a container where it was pressurized or refrigerated, it may first escape and behave as a heavy gas and sink in the air (even if it has a Vapor Density value less than 1). Also, the Specific Gravity comparisons are for fresh water (density 1.0 g/mL). If your spill is in salt water (density about 1.027 g/mL), you need to adjust the point of comparison. There are some chemicals that will sink in fresh water and float in salt water.
| Chemical Formula: |
|
Flash Point: data unavailable
Lower Explosive Limit (LEL): data unavailable
Upper Explosive Limit (UEL): data unavailable
Autoignition Temperature: data unavailable
Melting Point: data unavailable
Vapor Pressure: data unavailable
Vapor Density (Relative to Air): data unavailable
Specific Gravity: data unavailable
Boiling Point: data unavailable
Molecular Weight: data unavailable
Water Solubility: data unavailable
Ionization Energy/Potential:
13.60 eV
[From NPG: Hydrogen cyanide]
(NIOSH, 2023)
IDLH:
50 ppm
[From NPG: Hydrogen cyanide]
(NIOSH, 2023)
AEGLs (Acute Exposure Guideline Levels)
| Exposure Period | AEGL-1 | AEGL-2 | AEGL-3 |
|---|---|---|---|
| 10 minutes | 2.5 ppm | 17 ppm | 27 ppm |
| 30 minutes | 2.5 ppm | 10 ppm | 21 ppm |
| 60 minutes | 2 ppm | 7.1 ppm | 15 ppm |
| 4 hours | 1.3 ppm | 3.5 ppm | 8.6 ppm |
| 8 hours | 1 ppm | 2.5 ppm | 6.6 ppm |
(NAC/NRC, 2023)
ERPGs (Emergency Response Planning Guidelines)
| Chemical | ERPG-1 | ERPG-2 | ERPG-3 |
|---|---|---|---|
| Hydrogen Cyanide (74-90-8) | NA | 10 ppm | 25 ppm |
NA = not appropriate.
(AIHA, 2022)
PACs (Protective Action Criteria)
| Chemical | PAC-1 | PAC-2 | PAC-3 | |
|---|---|---|---|---|
| Hydrogen cyanide; (Hydrocyanic acid) (74-90-8) | 2 ppm | 7.1 ppm | 15 ppm | LEL = 56000 ppm |
(DOE, 2018)
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The
Regulatory Information fields
include information from
the U.S. Environmental Protection Agency's Title III Consolidated List of
Lists,
the U.S. Cybersecurity and Infrastructure Security Agency's Chemical Facility
Anti-Terrorism Standards,
and the U.S. Occupational Safety and Health Administration's
Process Safety Management of Highly Hazardous Chemicals Standard List
(see more about these
data sources).
EPA Consolidated List of Lists
| Regulatory Name | CAS Number/ 313 Category Code |
EPCRA 302 EHS TPQ |
EPCRA 304 EHS RQ |
CERCLA RQ | EPCRA 313 TRI |
RCRA Code |
CAA 112(r) RMP TQ |
|---|---|---|---|---|---|---|---|
| Cyanide Compounds | N106 | & | 313 | ||||
| Hydrocyanic acid | 74-90-8 | 100 pounds | 10 pounds | 10 pounds | X | P063 | 2500 pounds |
| Hydrogen cyanide | 74-90-8 | 100 pounds | 10 pounds | 10 pounds | 313 | P063 | 2500 pounds |
- "X" indicates that this is a second name for an EPCRA section 313 chemical already included on this consolidated list. May also indicate that the same chemical with the same CAS number appears on another list with a different chemical name.
- & indicates that no RQ is assigned to this generic or broad class, although the class is a CERCLA hazardous substance. See 50 Federal Register 13456 (April 4, 1985).
(EPA List of Lists, 2022)
CISA Chemical Facility Anti-Terrorism Standards (CFATS)
| RELEASE | THEFT | SABOTAGE | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Chemical of Interest | CAS Number | Min Conc | STQ | Security Issue |
Min Conc | STQ | Security Issue |
Min Conc | STQ | Security Issue |
| Hydrocyanic acid | 74-90-8 | 1.00 % | 2500 pounds | toxic | ||||||
| Hydrogen cyanide; [Hydrocyanic acid] | 74-90-8 | 4.67 % | 15 pounds | WME | ||||||
- WME = weapons of mass effect.
(CISA, 2007)
OSHA Process Safety Management (PSM) Standard List
| Chemical Name | CAS Number | Threshold Quantity (TQ) |
|---|---|---|
| Hydrogen Cyanide, Anhydrous | 74-90-8 | 1000 pounds |
(OSHA, 2019)
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This section provides a listing of alternate names for this chemical,
including trade names and synonyms.
- CARBON HYDRIDE NITRIDE (CHN)
- EVERCYN
- FORMIC ANAMMONIDE
- FORMONITRILE
- HYDROCYANIC ACID
- HYDROCYANIC ACID, AQUEOUS SOLUTION, WITH NOT MORE THAN 20% HYDROGEN CYANIDE
- HYDROCYANIC ACID, [AQUEOUS SOLUTION < = 20% HYDROCYANIC ACID]
- HYDROGEN CYANIDE
- HYDROGEN CYANIDE, AQUEOUS SOLUTION, WITH NOT MORE THAN 20% HYDROGEN CYANIDE
- PRUSSIC ACID
Version 3.0.0