HF is highly corrosive to metals, glass, skin, tissues and bones.
Any HF work must be performed within a chemical fume hood.
HF is one of the most corrosive inorganic acids. Per GHS classification of chemicals, HF is both a physical hazard (corrosive to metal, glass, enamel, etc) and a health hazard (acute poison and corrosive to skin, eyes, respiratory system, bones, etc.) as shown in the pictograms below.
- HF is acutely toxic and extremely destructive to the body tissue and respiratory tract.
- Exposures to HF will result in skin burns. Dermal exposure will cause sever and painful burns.
- HF in any concentration and quantity is highly hazardous to the human body system.
Below are example pictograms, hazard statements, signal words, and risk statements for different HF concentrations in water or other formulations.
Hazards and Signals
HF conc. ≥ 3M ( ≥ 6%)
Danger - Corosive to respiratory and body systems, eye, and bones.
Ingesting ~1.5 ml of 40% HF is fatal.
Acutely toxic if inhaled, in contact skin, and if swallowed.
|Warning - Corrosive to respiratory and body systems eyes, bones.|
(Conc. HF is typically used for stripping industrial parts made of stainless steel.
HF conc. 0.05 M to 0.5 M
Danger - Corrosive to respiratory and body systems, eyes, and bones.
|Toxic if inhaled, in contact with skin, and if swallowed.|
|Warning - Corrosive to metals||Corrosive to metals|
|HF conc. 0.05 M to 0.5 M|
(0.1 to 1%)
|Danger - Corrosive to respiratory and body systems eyes and bones|
Harmful if inhaled, in contact with skin, and if swallowed.
Irritant for the eye, the respiratory track and the skin.
Risk Reduction Assessment
Whenever possible, researchers should consider elimination or substitution of HF with less dangerous reagents, changing procedures to minimize the amount of HF used, or alternate processes. A basic risk assessment for various activities including risk minimization recommendations for safe handling of HF is summarized below.
HF Storage or Process Application
Recommendations For Risk Reduction
Typical Storage, Usage Quantity and Frequency of Use.
Storage or Process Risks
|Storage (concentrated acid)||More than two 500 ml bottles (40% higher concentration)|
|Two 500 ml HF bottles (40% or higher concentration)|
|One 500 ml HF bottle (40% or higher concentration)|
|Storage (concentrated acid)||Diluted HF solutions and synthetic reagents|
|Aliquoting, pouring or dispensing HF to reaction vessels|
Pouring or dispensing to reaction vessels per event, twice monthly.
|Digestion of geologic rocks or clay materials||2 to 20 ml per sample and no more than 10 samples per event, twice monthly.|
(Digestion is performed with sash closed and therefore risk is lower than the dynamic pouring/ dispensation activity.)
< 2 ml per sample and no more than 5 samples, twice monthly
|Cleaning/etching of silicon wafer, metal, or glass surface||2-10 ml per sample and no more than 10 samples, twice monthly.|
< 2 ml per sample, no more than 5 samples, twice monthly
|Pyridinium hydrofluoride (synthetic reagent)||<5 ml per sample per event.|
|Dilute trifluoroacetic acid (TFA) in water||Typically used as 0.1% TFA in water as HPLC mobile phase|
|Spill cleanup (HF spill outside of fume hood)||Any quantity and any concentration outside of the fume hood.|
(within a fume hood)
|5 to 20 ml|
(Both concentrated and dilute HF)
(Both concentrated and dilute HF)
|Waste Disposal: Transport of either unused HF or diluted HF soln.|
Concentrated HF soln: