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Chemical Datasheet
HYDROFLUORIC ACID, SOLUTION |
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Chemical Identifiers
CAS Number |
UN/NA Number |
DOT Hazard Label |
USCG CHRIS Code |
- 7664-39-3
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NIOSH Pocket Guide |
International Chem Safety Card |
Hydrogen fluoride
|
- HYDROFLUORIC ACID (70% AQUEOUS SOLUTION)
- HYDROGEN FLUORIDE
|
NFPA 704
General Description
A colorless fuming mobile aqueous solution with a pungent odor. Corrosive to metals and tissue. Highly toxic by ingestion and inhalation. Exposure to fumes or very short contact with liquid may cause severe painful burns; penetrates skin to cause deep-seated ulceration that may lead to gangrene.
Hazards
Reactivity Alerts
- Water-Reactive
- Air-Reactive
Air & Water Reactions
Fumes in air. Fumes are highly irritating, corrosive, and poisonous. Generates much heat on dissolution [Merck, 11th ed., 1989]. Heat can cause spattering, fuming, etc.
Fire Hazard
Excerpt from ERG Guide 157 [Substances - Toxic and/or Corrosive (Non-Combustible / Water-Sensitive)]:
Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive and/or toxic fumes. UN1802, UN2032, UN3084, UN3093, UN1796 (above 50%), UN1826 (above 50%), and UN2031 (above 65%) may act as oxidizers. Also consult ERG Guide 140. Vapors may accumulate in confined areas (basement, tanks, hopper/tank cars, etc.). Substance may react with water (some violently), releasing corrosive and/or toxic gases and runoff. Corrosives in contact with metals may evolve flammable hydrogen gas. Containers may explode when heated or if contaminated with water. (ERG, 2024)
Health Hazard
Excerpt from ERG Guide 157 [Substances - Toxic and/or Corrosive (Non-Combustible / Water-Sensitive)]:
TOXIC and/or CORROSIVE; inhalation, ingestion or contact (skin, eyes) with vapors, dusts or substance may cause severe injury, burns or death. Reaction with water or moist air may release toxic, corrosive or flammable gases. Reaction with water may generate much heat that will increase the concentration of fumes in the air. Fire will 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, 2024)
Reactivity Profile
HYDROFLUORIC ACID attacks glass and any other silica containing material. May react with common metals (iron, steel) to generate flammable hydrogen gas if diluted below 65%. Reacts exothermically with chemical bases (examples: amines, amides, inorganic hydroxides). Can initiate polymerization in certain alkenes. Reacts with cyanide salts and compounds to release gaseous hydrogen cyanide. May generate flammable and/or toxic gases with dithiocarbamates, isocyanates, mercaptans, nitrides, nitriles, sulfides. Additional gas-generating reactions may occur with sulfites, nitrites, thiosulfates (to give H2S and SO3), dithionites (SO2), and carbonates. Can catalyze (increase the rate of) chemical reactions. Reacts explosively with cyanogen fluoride, methanesulfonic acid or glycerol mixed with nitric acid. Reacts violently with arsenic trioxide, phosphorus pentachloride, acetic anhydride, alkali metals, ammonium hydroxide, chlorosulfonic acid, ethylenediamine, fluorine, potassium permanganate, oleum, propylene oxide, vinyl acetate, mercury(II) oxide. Emits highly corrosive fumes of hydrogen fluoride gas when heated [Sax, 9th ed., 1996, p. 1839]. Contact with many silicon compounds and metal silicides causes violent evolution of gaseous silicon tetrafluoride [Mellor, 1956, Vol. 2, suppl. 1, p. 121].
Mixing in equal molar portions with any of the following substances in a closed container caused the temperature and pressure to increase: acetic anhydride, 2-aminoethanol, chlorosulfonic acid, aqueous ammonia (48.7%), ethylenediamine, ethyleneimine, oleum, aqueous sulfuric acid (48.7%), aqueous sodium hydroxide (48.7%), propylene oxide, vinyl acetate [NFPA 1991].
Belongs to the Following Reactive Group(s)
- Fluoride Salts, Soluble
- Acids, Weak
- Water and Aqueous Solutions
Potentially Incompatible Absorbents
Use caution: Liquids with this reactive group classification have been
known to react with the
absorbents
listed below.
- Mineral-Based & Clay-Based Absorbents
- Sand
- Dirt/Earth
Response Recommendations
Isolation and Evacuation
Excerpt from ERG Guide 157 [Substances - Toxic and/or Corrosive (Non-Combustible / Water-Sensitive)]:
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: Increase the immediate precautionary measure distance, in the downwind direction, as necessary.
FIRE: If tank, rail tank car or highway tank 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, 2024)
Firefighting
Excerpt from ERG Guide 157 [Substances - Toxic and/or Corrosive (Non-Combustible / Water-Sensitive)]:
Note: Some foams will react with the material and release corrosive/toxic gases.
SMALL FIRE: CO2 (except for Cyanides), dry chemical, dry sand, alcohol-resistant foam.
LARGE FIRE: Water spray, fog or alcohol-resistant foam. If it can be done safely, move undamaged containers away from the area around the fire. Avoid aiming straight or solid streams directly onto the product. Dike runoff from fire control for later disposal.
FIRE INVOLVING TANKS, RAIL TANK CARS OR HIGHWAY TANKS: 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 in direct contact with flames. (ERG, 2024)
Non-Fire Response
Excerpt from ERG Guide 157 [Substances - Toxic and/or Corrosive (Non-Combustible / Water-Sensitive)]:
ELIMINATE all ignition sources (no smoking, flares, sparks or flames) from immediate area. All equipment used when handling the product must be grounded. Do not touch damaged containers or spilled material unless wearing appropriate protective clothing. Stop leak if you can do it without risk. A vapor-suppressing foam may be used to reduce vapors. DO NOT GET WATER INSIDE CONTAINERS. Use water spray to reduce vapors or divert vapor cloud drift. Avoid allowing water runoff to contact spilled material. Prevent entry into waterways, sewers, basements or confined areas.
SMALL SPILL: Cover with DRY earth, DRY sand or other non-combustible material followed with plastic sheet to minimize spreading or contact with rain. Use clean, non-sparking tools to collect material and place it into loosely covered plastic containers for later disposal. (ERG, 2024)
Protective Clothing
Excerpt from ERG Guide 157 [Substances - Toxic and/or Corrosive (Non-Combustible / Water-Sensitive)]:
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, 2024)
DuPont Tychem® Suit Fabrics
Normalized Breakthrough Times (in Minutes)
Chemical |
CAS Number |
State |
QS |
QC |
SL |
C3 |
TF |
TP |
RC |
TK |
RF |
Hydrofluoric acid (48-51%) |
7664-39-3 |
Liquid |
400 |
446 |
>480 |
>480 |
>480 |
15 |
>480 |
>480 |
>480 |
Hydrofluoric acid (60%) |
7664-39-3 |
Liquid |
|
|
|
|
52 |
|
|
|
|
Hydrofluoric acid (70%) |
7664-39-3 |
Liquid |
|
|
143 |
126 |
35 |
|
>480 |
>480 |
>480 |
Hydrogen fluoride (20-27°C, gaseous) |
7664-39-3 |
Vapor |
|
imm |
93*/134 |
186 |
imm |
imm |
130 |
>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, 2024)
First Aid
Excerpt from ERG Guide 157 [Substances - Toxic and/or Corrosive (Non-Combustible / Water-Sensitive)]:
Refer to the "General First Aid" section. Specific First Aid: For corrosives, in case of contact, immediately flush skin or eyes with running water for at least 30 minutes. Additional flushing may be required. In case of skin contact with Hydrofluoric acid (UN1790), if calcium gluconate gel is available, rinse 5 minutes, then apply gel. Otherwise, continue rinsing until medical treatment is available. (ERG, 2024)
Physical Properties
Flash Point: data unavailable
Lower Explosive Limit (LEL): data unavailable
Upper Explosive Limit (UEL): data unavailable
Autoignition Temperature:
Not flammable
(USCG, 1999)
Melting Point:
-92.2°F
for 70% solution
(ICSC, 2024)
Vapor Pressure:
150 mmHg
at 77°F
(partial pressure for 70% solution)
(ICSC, 2024)
Vapor Density (Relative to Air):
1.86
at 77°F
for 70% solution
(ICSC, 2024)
- Heavier than air; will sink
Specific Gravity:
1.23
for 70% solution
(ICSC, 2024)
- Denser than water; will sink
Boiling Point:
152°F
at 760 mmHg
for 70% solution
(ICSC, 2024)
Molecular Weight: data unavailable
Water Solubility:
Miscible
(ICSC, 2024)
Ionization Energy/Potential:
15.98 eV
[From NPG: Hydrogen fluoride]
(NIOSH, 2024)
IDLH:
30 ppm
[From NPG: Hydrogen fluoride]
(NIOSH, 2024)
AEGLs (Acute Exposure Guideline Levels)
Final AEGLs for Hydrogen fluoride (7664-39-3)
Exposure Period |
AEGL-1 |
AEGL-2 |
AEGL-3 |
10 minutes |
1 ppm |
95 ppm |
170 ppm |
30 minutes |
1 ppm |
34 ppm |
62 ppm |
60 minutes |
1 ppm |
24 ppm |
44 ppm |
4 hours |
1 ppm |
12 ppm |
22 ppm |
8 hours |
1 ppm |
12 ppm |
22 ppm |
(NAC/NRC, 2024)
ERPGs (Emergency Response Planning Guidelines)
Chemical |
ERPG-1 |
ERPG-2 |
ERPG-3 |
Hydrogen Fluoride (7664-39-3) **
|
2 ppm  |
20 ppm |
50 ppm |
(AIHA, 2022)
PACs (Protective Action Criteria)
Chemical |
PAC-1 |
PAC-2 |
PAC-3 |
Hydrogen fluoride; (Hydrofluoric acid) (7664-39-3)
|
1 ppm |
24 ppm |
44 ppm |
(DOE, 2024)
Regulatory Information
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 |
Hydrofluoric acid |
7664-39-3 |
100 pounds |
100 pounds |
100 pounds |
X |
U134 |
|
Hydrofluoric acid (conc. 50% or greater) |
7664-39-3 |
100 pounds |
100 pounds |
100 pounds |
X |
U134 |
1000 pounds |
Hydrogen fluoride |
7664-39-3 |
100 pounds |
100 pounds |
100 pounds |
313 |
U134 |
|
Hydrogen fluoride (anhydrous) |
7664-39-3 |
100 pounds |
100 pounds |
100 pounds |
X |
U134 |
1000 pounds |
(EPA List of Lists, 2024)
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 |
Hydrofluoric acid (conc. 50% or greater) |
7664-39-3 |
50.00 % |
1000 pounds |
toxic |
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Hydrogen fluoride (anhydrous) |
7664-39-3 |
1.00 % |
1000 pounds |
toxic |
42.53 % |
45 pounds |
WME |
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|
|
(CISA, 2007)
OSHA Process Safety Management (PSM) Standard List
Chemical Name |
CAS Number |
Threshold Quantity (TQ) |
Hydrofluoric Acid, Anhydrous |
7664-39-3 |
1000 pounds |
Hydrogen Fluoride |
7664-39-3 |
1000 pounds |
(OSHA, 2019)
Alternate Chemical Names
- ALSURF 45
- ANTISAL 2B
- AQUEOUS HYDROGEN FLUORIDE (I.E., HYDROFLUORIC ACID)
- FLUORHYDRIC ACID
- FLUORIC ACID
- FLUORINE HYDRIDE (FH)
- FLUORINE MONOHYDRIDE
- HF-A
- HYDROFLUORIC ACID
- HYDROFLUORIC ACID (CONC. 50% OR GREATER)
- HYDROFLUORIC ACID, SOLUTION
- HYDROGEN FLUORIDE (HF)
- HYDROGEN FLUORIDE (HYDROFLUORIC ACID)
- HYDROGEN MONOFLUORIDE