EPA Extremely Hazardous Substances List. Community Right-To-Know List. EPA Genetic Toxicology Program. Reported in EPA TSCA Inventory.

OSHA PEL: TWA 3 ppm; STEL 6 ppm (F)
ACGIH TLV: CL 3 ppm (F); BEI: 3 mg/g creatinine of fluorides in urine prior to shift; 10 mg/g creatinine of fluorides in urine at end of shift.
DFG MAK: 3 ppm (2.5 mg/m³); BAT 7.0 mg/g creatinine in urine at end of shift
NIOSH REL: (HF) TWA 2.5 mg(F)/m³; CL 5.0 mg(F)/m³/15M
DOT Classification:  8; Label: Corrosive, Poison

For occupational chemical analysis use NIOSH: Fluorides, 7902; Acids, Inorganic, 7903.

Hydrofluoric acid (CAS NO.7664-39-3) is a chemical compound with the formula HF. It is the principal industrial source of fluorine, often in the aqueous form as hydrofluoric acid. The hot, gaseous it is either absorbed in water or liquefied; refrigeration is employed to obtain the anhydrous product needed for fluorocarbon manufacture and other uses. Although it is corrosive, concentrations of 60% and above can be handled in steel at lower temperatures; load, carbon and special alloys are also used in the process equipment.It is A solution of hydrogen fluoride in water. It is a colorless fuming liquid which can cause painful burns.

Physical properties about Hydrofluoric acid are: 
(1)mp: -35°C; (2)bp: 105°C; (3)density: 1.15 g/mL at 25 °C(lit.); (4)vapor density: 1.27 (vs air); (5)vapor pressure: 25 mm Hg ( 20 °C); (6)Fp: 112°C; (7)Water Solubility: soluble; (8)Sensitive:Hygroscopic; (9)Merck:14,479

Preparation of Hydrofluoric acid: 
Hydrofluoric acid is produced by treatment of the mineral fluorite (CaF₂) with concentrated sulfuric acid. When combined at 265 °C, these two substances react to produce hydrogen fluoride and calcium sulfate according to the following chemical equation:
CaF₂ + H₂SO₄ → 2 HF + CaSO₄

Uses of Hydrofluoric acid: 
Hydrofluoric acid is the precursor to many important compounds including pharmaceuticals and polymers (e.g. Teflon). HF is widely used in the petrochemical industry and a component of many superacids. HF boils just below room temperature whereas the other hydrogen halides condense at much lower temperatures. Unlike the other hydrogen halides, HF is lighter than air and its odour is particularly penetrating, which can damage the lungs. Hydrofluoric acid is used to prepare fluorocarbons and one:third of the total goes to the aluminum industry, where synthetic cryolite, sodium aluminum fluoride, is a major constituent of the electrolyte. It is also consumed in the melting and refining of secondary aluminum. Other uses of hydrofluoric acid are found in the metals and petroleum industries.

When you are using Hydrofluoric acid, please be cautious about it as the following:
1.In case of contact with eyes, rinse immediately with plenty of water and seek medical advice;
2.Wear suitable protective clothing, gloves and eye/face protection;
3.In case of accident or if you feel unwell, seek medical advice immediately (show label where possible);

You can still convert the following datas into molecular structure:
(1)InChI=1S/FH/h1H;
(2)InChIKey=KRHYYFGTRYWZRS-UHFFFAOYSA-N;
(3)SmilesF;

The toxicity data of Hydrofluoric acid is as follows: