Agent Name

Hydrogen fluoride

Alternative Name

Hydrofluoric acid

CAS Number

7664-39-3

Formula

F-H

Major Category

Toxic Gases & Vapors

Synonyms

Anhydrous hydrogen fluoride; Aqueous hydrogen fluoride; Hydrofluoric acid; HF-A; [NIOSH] Rubigine; Hydrofluoride; Fluorhydric acid; Antisal 2B; [ChemIDplus] UN1052

Category

Acids, Inorganic

Description

Colorless gas or fuming liquid (below 67 degrees F) with a strong, irritating odor; Note: Shipped in cylinders; [NIOSH]

Sources/Uses

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]

Comments

Aqueous hydrogen fluoride = hydrofluoric acid; [NIOSH] Industrial solutions of 45% and 53% are sold commercially. [ACGIH] Over-the-counter solutions usually contain 6-12%. Adverse effects caused by different concentrations of solutions include immediate burns after contact with 50% and greater, delayed pain and swelling up to 8 hours after contact with 20-50%, and injury delayed by 12-24 hours after contact with 20% or less. [ATSDR Medical Management] Solutions 30-70% are highly corrosive to skin; [Quick CPC] Listed as one of the "major irritant airborne toxicants"; [LaDou, p. 523] The following chemicals can release HF when spilled in water: Fluorosulfonic acid, Antimony pentafluoride, Iodine pentafluoride, Uranium hexafluoride, Bromine trifluoride, and Bromine pentafluoride. [ERG 2016] See the Process, "Toxic Gas from Spilling Chemical in Water." See the Disease, "Hydrofluoric acid, toxic effect." Hydrogen fluoride is fibrogenic to the lungs in the context of an acute inhalation exposure complicated by bronchiolitis obliterans.

Reference Link

ATSDR Medical Management - Hydrogen fluoride

Exposure Assessment
Skin Designation (ACGIH)

Yes

TIH

Yes

TLV (ACGIH)

0.5 ppm, as F

Ceiling (ACGIH)

2 ppm, as F

PEL (OSHA)

3 ppm, as F

MAK

1 ppm, as F

IDLH (NIOSH)

30 ppm, as F

Excerpts from Documentation for IDLHs

It has been stated that 50 ppm may be fatal when inhaled for 30 to 60 minutes [Deichmann and Gerarde 1969]. Volunteers tolerated concentrations as high as 4.7 ppm for 6 hours per day for 10 to 50 days without severe adverse effects [Largent 1961]

Vapor Pressure

783 mm Hg

Odor Threshold Low

0.04 ppm

Lethal Concentration

LC50 (rat) = 1,276 ppm/1 hr

Explanatory Notes

Odor threshold from AIHA; The Guide from the Emergency Response Guidebook is for " Hydrogen fluoride, anhydrous." The 10-minute ERPGs for HF are: 1: 2 ppm; 2: 50 ppm; and 3: 170 ppm; [AIHA]

Reference Link

ICSC: Hydrogen fluoride

Adverse Effects
Toxic Pneumonitis

Yes

Fibrogenic

Yes

Dermatotoxin

Skin Burns

Links to Other NLM Databases
Health Studies

Human Health Effects from Hazardous Substances Data Bank:

Toxicity Information

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Chemical Information

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Biomedical References

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Related Information in HazMap
Diseases

Occupational diseases associated with exposure to this agent:

Processes

Industrial Processes with risk of exposure:

Activities

Activities with risk of exposure: