Hydrofluoric Acid

1Identification

Name

Hydrofluoric Acid

IUPAC name

fluorane

CAS number

7664-39-3

EC number

231-634-8

Molecular formula

FH

Molecular weight

20.0064 g/mol

InChIKey

KRHYYFGTRYWZRS-UHFFFAOYSA-N

SMILES

F

PubChem CID

14917

Synonyms

HYDROFLUORIC ACID, Hydrogen fluoride, Fluorhydric acid, Hydrofluoride, Rubigine, Fluorwasserstoff, Antisal 2B, Hydrofluoricum acidum, Fluorowodor, Fluorwaterstof, Acido fluoridrico, Acide fluorhydrique, fluoridohydrogen, fluoric acid

Recommended uses

• Hydrogen fluoride is used in the production of most fluorine-containing chemicals. It is used in the production of refrigerants, herbicides, pharmaceuticals, high-octane gasoline, aluminum, plastics, electrical components, and fluorescent light bulbs. Anhydrous hydrogen fluoride is used as a catalyst in the petroleum alkylation, a process that increases the octane rating of petroleum. In uranium chemicals production, hydrogen fluoride is used to convert uranium oxide (yellow cake, U3O8) to UF4 before further fluorination to UF6. Aqueous hydrofluoric acid is used in stainless steel pickling, glass etching, metal coatings, exotic metal extraction, and quartz purification.
  EPA Hazardous Air Pollutants
• Used as a catalyst and fluorinating agent; used to etch glass, pickle stainless steel, and control pH in oil well operations; [ACGIH] Used as a wet etchant in semiconductor manufacturing at a standard concentration of 49%; [CSH, p. 46]
  Haz-Map, Information on Hazardous Chemicals and Occupational Diseases
• Steel Producing [Category: Industry] Acid and Alkali Cleaning of Metals [Category: Clean] Electroplating [Category: Plate] Petroleum Production and Refining [Category: Industry] Semiconductor Manufacturing [Category: Industry] Glass Manufacturing [Category: Industry]
  Haz-Map, Information on Hazardous Chemicals and Occupational Diseases
• Adhesion/cohesion promoter Etching agent Intermediate Brightener Cleaning agent Catalyst Not Known or Reasonably Ascertainable Processing aids not otherwise specified Semiconductor and photovoltaic agent Plating agent Chemical reaction regulator Solvent Other
  EPA Chemical Data Reporting (CDR)
• Other Not Known or Reasonably Ascertainable Cleaning agent Brightener Laboratory chemicals Etching agent
  EPA Chemical Data Reporting (CDR)

Use categories: Chemical Classes -> Inorganic substances

Description

• Hydrogen fluoride is a colorless, fuming liquid or gas with a strong, irritating odor. It is usually shipped in steel cylinders as a compressed gas. Hydrogen fluoride readily dissolves in water to form colorless hydrofluoric acid solutions; dilute solutions are visibly indistinguishable from water.
  Agency for Toxic Substances and Disease Registry (ATSDR)
• Hydrofluoric acid, solution appears as 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.
  CAMEO Chemicals
• Hydrogen fluoride, anhydrous appears as a colorless fuming liquid boiling at 67 °F. Shipped as a liquid confined under its own vapor pressure. Corrosive to metals and tissue. Very short contact with fumes or small quantities of the liquid can cause severe, painful burns. Vapors are heavier than air. Used as a catalyst and raw material in chemical manufacture. Rate of onset: Immediate & Delayed Persistence: Minutes to hours Odor threshold: 0.4 ppm Source/use/other hazard: Aluminum and other metal industries; insecticide manufacturing-corrosive liq.
  CAMEO Chemicals

2Hazard identification

Signal word

Danger

Pictograms

GHS05, GHS06

Classification source

Regulation (EC) No 1272/2008 of the European Parliament and of the Council

Precautionary statements

Other reported classifications

10 classification records exist across sources. Differences usually reflect purity, physical form or impurities.

Health hazards

• 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)
  CAMEO Chemicals
• Ingestion of an estimated 1.5 grams produced sudden death without gross pathological damage. Repeated ingestion of small amounts resulted in moderately advanced hardening of the bones. Contact of skin with anhydrous liquid produces severe burns. Inhalation of anhydrous hydrogen fluoride or hydrogen fluoride mist or vapors can cause severe respiratory tract irritation that may be fatal. (EPA, 1998)
  CAMEO Chemicals
• · 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.
  Emergency Response Guidebook (ERG)

Fire hazards

• 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)
  CAMEO Chemicals
• When heated, it emits highly corrosive fumes of fluorides. Its corrosive action on metals can result in formation of hydrogen in containers and piping to create fire hazard. Toxic and irritating vapors are generated when heated. Will attack glass, concrete, and certain metals, especially those containing silica, such as cast iron. Will attack natural rubber, leather, and many organic materials. May generate flammable hydrogen gas in contact with some metals. (EPA, 1998)
  CAMEO Chemicals
• · 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 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.
  Emergency Response Guidebook (ERG)

Hazards summary

• Hydrogen fluoride is a colorless, fuming liquid or gas with a strong, irritating odor. It is usually shipped in steel cylinders as a compressed gas. Hydrogen fluoride readily dissolves in water to form colorless hydrofluoric acid solutions; dilute solutions are visibly indistinguishable from water.
  Agency for Toxic Substances and Disease Registry (ATSDR)
• Hydrogen fluoride is used in the production of aluminum and chlorofluorocarbons, and in the glass etching and chemical industries. Acute (short-term) inhalation exposure to gaseous hydrogen fluoride can cause severe respiratory damage in humans, including severe irritation and lung edema. Severe eye irritation and skin burns may occur following eye or skin exposure in humans. Chronic (long-term) exposure in workers has resulted in skeletal fluorosis, a bone disease. Animal studies have reported effects on the lungs, liver, and kidneys from acute and chronic inhalation exposure to hydrogen fluoride. Studies investigating the carcinogenic potential of hydrogen fluoride are inconclusive.
  EPA Hazardous Air Pollutants

3Composition / information on ingredients

This page describes the pure substance. Commercial products may be solutions or mixtures. Check Section 3 of your supplier's SDS for concentrations and other ingredients.

4First-aid measures

• 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)
  CAMEO Chemicals
• Warning: Hydrogen fluoride is highly corrosive. Effects may be delayed from 1 to 24 hours. Caution is advised. Signs and Symptoms of Acute Hydrogen Fluoride Exposure: Acute exposure to hydrogen fluoride will result in irritation, burns, ulcerous lesions, and necrosis of the eyes, skin, and mucous membranes. Total destruction of the eyes is possible. Other effects include nausea, vomiting, diarrhea, pneumonitis (inflammation of the lungs), and circulatory collapse. Emergency Life-Support Procedures: Acute exposure to hydrogen fluoride may require decontamination and life support for the victims.
  CAMEO Chemicals
• General First Aid: · Call 911 or emergency medical service. · Ensure that medical personnel are aware of the material(s) involved, take precautions to protect themselves and avoid contamination. · Move victim to fresh air if it can be done safely. · Administer oxygen if breathing is difficult. · If victim is not breathing: -- DO NOT perform mouth-to-mouth resuscitation; the victim may have ingested or inhaled the substance. -- If equipped and pulse detected, wash face and mouth, then give artificial respiration using a proper respiratory medical device (bag-valve mask, pocket mask equipped with a one-way valve or other device).
  Emergency Response Guidebook (ERG)
• (General first aid procedures) Eye: Irrigate immediately (solution/liquid) Skin: Water flush immediately (solution/liquid) Breathing: Respiratory support Swallow: Medical attention immediately (solution)
  The National Institute for Occupational Safety and Health (NIOSH)

Symptoms of exposure

• Burning sensation. Sore throat. Cough. Laboured breathing. Shortness of breath. Nausea. Vomiting. Symptoms may be delayed.
  ILO-WHO International Chemical Safety Cards (ICSCs)
• MAY BE ABSORBED! Redness. Pain. Serious skin burns. Blisters. See Inhalation.
  ILO-WHO International Chemical Safety Cards (ICSCs)
• Redness. Pain. Severe burns.
  ILO-WHO International Chemical Safety Cards (ICSCs)

5Fire-fighting measures

• Use water spray, alcohol-resistant foam, dry chemical or carbon dioxide. Wear self-contained breathing apparatus for firefighting if necessary.
  Hazardous Substances Data Bank (HSDB)

Hazardous combustion products

• Reacts with water or steam to produce toxic and corrosive fumes.
  Hazardous Substances Data Bank (HSDB)

6Accidental release measures

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)
  CAMEO Chemicals
• Excerpt from ERG Guide 125 [Gases - Toxic and/or Corrosive]: IMMEDIATE PRECAUTIONARY MEASURE: Isolate spill or leak area for at least 100 meters (330 feet) in all directions. SPILL: See ERG Tables 1 and 3 - Initial Isolation and Protective Action Distances on the UN/NA 1052 datasheet. FIRE: If tank, rail tank car or highway tank is involved in a fire, ISOLATE for 1600 meters (1 mile) in all directions; also, consider initial evacuation for 1600 meters (1 mile) in all directions. (ERG, 2024)
  CAMEO Chemicals

Spill cleanup

• Evacuate danger area! Consult an expert! Personal protection: gas-tight chemical protection suit including self-contained breathing apparatus. Do NOT let this chemical enter the environment. Ventilation. Remove vapour with fine water spray.
  ILO-WHO International Chemical Safety Cards (ICSCs)
• ACCIDENTAL RELEASE MEASURES; Personal precautions, protective equipment and emergency procedures: Wear respiratory protection. Avoid breathing vapours, mist or gas. Ensure adequate ventilation. Evacuate personnel to safe areas. Environmental precautions: Prevent further leakage or spillage if safe to do so. Do not let product enter drains. Methods and materials for containment and cleaning up: Soak up with inert absorbent material and dispose of as hazardous waste. Keep in suitable, closed containers for disposal.
  Hazardous Substances Data Bank (HSDB)
• 1. Ventilate area of spill or leak to disperse gas. 2. If in gaseous form, stop flow of gas. If source of leak is cylinder & leak cannot be stopped ... remove ... to safe place in open air, & repair leak or allow cylinder to empty. 3. If in liq form, allow to vaporize & disperse the gas.
  Hazardous Substances Data Bank (HSDB)

7Handling and storage

• Cool. Well closed. Fireproof if in building. Ventilation along the floor. Separated from food and feedstuffs and incompatible materials. Store in an area without drain or sewer access. See Chemical Dangers.
  ILO-WHO International Chemical Safety Cards (ICSCs)
• Hydrogen fluoride should be stored in cool, dry, well ventilated areas out of the direct rays of the sun.
  Hazardous Substances Data Bank (HSDB)
• Keep container tightly closed in a dry and well-ventilated place. Containers which are opened must be carefully resealed and kept upright to prevent leakage. Store in corrosive resistant polyethylene container with a resistant inner liner. Do not store in glass Storage class (TRGS 510): Non-combustible, acute toxic Cat. 1 and 2 / very toxic hazardous materials
  Hazardous Substances Data Bank (HSDB)

8Exposure controls / personal protection

Personal protective equipment

• 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)
  CAMEO Chemicals
• Excerpt from NIOSH Pocket Guide for Hydrogen fluoride: Skin: PREVENT SKIN CONTACT (LIQUID) - If this chemical is in liquid form, wear appropriate personal protective clothing to prevent skin contact. Eyes: PREVENT EYE CONTACT (LIQUID) - If this chemical is in liquid form, wear appropriate eye protection to prevent eye contact. Wash skin: WHEN CONTAMINATED (LIQUID) - If this chemical is in liquid form, the worker should immediately wash the skin when it becomes contaminated. Remove: WHEN WET OR CONTAMINATED (LIQUID) - If this chemical is in liquid form, work clothing that becomes wet or significantly contaminated should be removed and replaced.
  CAMEO Chemicals
• Workers should wear long rubber gauntlets, long rubber aprons, high rubber boots, & wide plastic face shield while handling hydrogen fluoride. Forced-air face masks should be worn if air concn ... is sufficiently high to cause nasal irritation.
  Hazardous Substances Data Bank (HSDB)
• There are some data (usually from immersion tests) suggesting breakthrough times of butyl rubber that are greater than one hour are not likely. There are some data suggesting the breakthrough times of polycarbonate to be approximately an hour or more.
  Hazardous Substances Data Bank (HSDB)

Respirator recommendations

• NIOSH/OSHA Up to 30 ppm: (APF = 10) Any chemical cartridge respirator with cartridge(s) providing protection against the compound of concern* (APF = 25) Any powered, air-purifying respirator with cartridge(s) providing protection against the compound of concern* (APF = 50) Any air-purifying, full-facepiece respirator (gas mask) with a chin-style, front- or back-mounted canister providing protection against the compound of concern (APF = 10) Any supplied-air respirator* (APF = 50) Any self-contained breathing apparatus with a full facepiece Emergency or planned entry into unknown concentrations or IDLH conditions: (APF = 10,000) Any self-contained breathing apparatus that has a full facepiece…
  The National Institute for Occupational Safety and Health (NIOSH)

9Physical and chemical properties

10Stability and reactivity

Reactivity

• 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.
  CAMEO Chemicals
• HYDROGEN FLUORIDE, ANHYDROUS attacks glass and any other silica containing material. May react with common metals (iron, steel) to generate flammable hydrogen gas if diluted below 65% with water. 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.
  CAMEO Chemicals
• 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.
  CAMEO Chemicals

Incompatible materials and hazardous reactions

• Metals, water or steam. [Note: Corrosive to metals. Will attack glass and concrete].
  Hazardous Substances Data Bank (HSDB)
• Interaction of the solid /bismuthic acid/ with 40% hydrofluoric acid is violent, ozonized oxygen being evolved.
  Hazardous Substances Data Bank (HSDB)
• Polymerization of cyanogen fluoride is rapid at ambient temp and explosive in presence of hydrogen fluoride.
  Hazardous Substances Data Bank (HSDB)

Chemical stability

• Stable under recommended storage conditions.
  Hazardous Substances Data Bank (HSDB)

11Toxicological information

Target organs

• Eyes, skin, respiratory system, bones
  The National Institute for Occupational Safety and Health (NIOSH)

Short-term exposure effects

• The substance is very corrosive to the eyes, skin and respiratory tract. Inhalation of the gas or vapour may cause lung oedema. Inhalation may cause asthma-like reactions (RADS). Exposure could cause asphyxiation due to swelling in the throat. Inhalation may cause pneumonitis. Exposure could cause hypocalcemia. The effects may be delayed. Exposure above the OEL could cause death.
  ILO-WHO International Chemical Safety Cards (ICSCs)

Long-term exposure effects

• Fluoride can accumulate in teeth, joints and bones. This may result in stained tooth enamel up to joint and bone disorders (fluorosis).
  ILO-WHO International Chemical Safety Cards (ICSCs)

12Ecological information

Not available in the public sources we compile. Check Section 12 of the supplier's SDS.

13Disposal considerations

• Generators of waste (equal to or greater than 100 kg/mo) containing this contaminant, EPA hazardous waste number D002 and U134, must conform with USEPA regulations in storage, transportation, treatment and disposal of waste.
  Hazardous Substances Data Bank (HSDB)
• SRP: Wastewater from contaminant suppression, cleaning of protective clothing/equipment, or contaminated sites should be contained and evaluated for subject chemical or decomposition product concentrations. Concentrations shall be lower than applicable environmental discharge or disposal criteria. Alternatively, pretreatment and/or discharge to a permitted wastewater treatment facility is acceptable only after review by the governing authority and assurance that "pass through" violations will not occur. Due consideration shall be given to remediation worker exposure (inhalation, dermal and ingestion) as well as fate during treatment, transfer and disposal.
  Hazardous Substances Data Bank (HSDB)
• Product: Offer surplus and non-recyclable solutions to a licensed disposal company. Contact a licensed professional waste disposal service to dispose of this material. Dissolve or mix the material with a combustible solvent and burn in a chemical incinerator equipped with an afterburner and scrubber. Contaminated packaging: Dispose of as unused product.
  Hazardous Substances Data Bank (HSDB)

14Transport information

UN numbers: UN 1052, UN 1790, UN 1005

Shipping name

• UN 1052; Hydrogen fluoride, anhydrous.
  Hazardous Substances Data Bank (HSDB)
• UN 1790; Hydrofluoric acid, with more than 60% strength; Hydrofluoric acid, with not more than 60% strength
  Hazardous Substances Data Bank (HSDB)

DOT hazard class

• Hydrofluoric acid, with more than 60 percent strength
  US Code of Federal Regulations, Hazardous Materials, 49 CFR Part 172
• UN1790
  US Code of Federal Regulations, Hazardous Materials, 49 CFR Part 172
• Class 8 Corrosive material (49 eCFR § 173.136)
  US Code of Federal Regulations, Hazardous Materials, 49 CFR Part 172

DOT label

• Corrosive Poison
  CAMEO Chemicals

UN classification

• UN Hazard Class: 8; UN Subsidiary Risks: 6.1; UN Pack Group: I
  ILO-WHO International Chemical Safety Cards (ICSCs)

Emergency Response Guidebook

• 1790 157
  Emergency Response Guidebook (ERG)
• 1052 125
  Emergency Response Guidebook (ERG)

How DOT hazard classes work →

15Regulatory information

• Listed as a hazardous air pollutant (HAP) generally known or suspected to cause serious health problems. The Clean Air Act, as amended in 1990, directs EPA to set standards requiring major sources to sharply reduce routine emissions of toxic pollutants. EPA is required to establish and phase in specific performance based standards for all air emission sources that emit one or more of the listed pollutants. Hydrofluoric acid is included on this list.
  Hazardous Substances Data Bank (HSDB)
• Hydrofluoric acid is designated as a hazardous substance under section 311(b)(2)(A) of the Federal Water Pollution Control Act and further regulated by the Clean Water Act Amendments of 1977 and 1978. These regulations apply to discharges of this substance. This designation includes any isomers and hydrates, as well as any solutions and mixtures containing this substance.
  Hazardous Substances Data Bank (HSDB)
• Persons in charge of vessels or facilities are required to notify the National Response Center (NRC) immediately, when there is a release of this designated hazardous substance, in an amount equal to or greater than its reportable quantity of 100 lb or 45.4 kg. The toll free number of the NRC is (800) 424-8802. The rule for determining when notification is required is stated in 40 CFR 302.4 (section IV. D.3.b).
  Hazardous Substances Data Bank (HSDB)
• D002; A solid waste containing hydrofluoric acid may become characterized as a hazardous waste when subjected to testing for corrosivity as stipulated in 40 CFR 261.21, and if so characterized, must be managed as a hazardous waste.
  Hazardous Substances Data Bank (HSDB)
• Hydrofluoric acid is an indirect food additive for use only as a component of adhesives.
  Hazardous Substances Data Bank (HSDB)

Overview of SDS regulations (OSHA HazCom, WHMIS, REACH/CLP) →

16Other information

Compiled from PubChem CID 14917 and the sources it aggregates (attributed inline). Data retrieved 2026-10-12. This summary describes the pure substance and is not a supplier SDS.