Hydrogen fluoride is an inorganic compound with the formula HF and is a colorless gas at temperatures above 67°F / 19°C or liquid at colder temperatures, both with a pungent odor. Even in liquid form, it fumes creating a very dangerous breathing hazard. When this compound is dissolved in water it's known as hydrofluoric acid. Hydrogen fluoride can be released when other compounds, such as ammonium fluoride (NH4F), are combined with water.
HF is used as a precursor to creating other chemical compounds from polymers and pharmaceuticals such as Prozac. Another common use for it is in the petrochemical industry as a component of superacids.
One of the common dangers to industrial workers is that it's extremely corrosive to a wide range of materials. HF can cause painful burns on the skin and severe eye damage.
Type: Electrochemical
Range: 0-10 ppm (0.1ppm resolution)
Low Alarm: 2.5 ppm
High Alarm: 5 ppm
STEL — 15 minutes — Short-Term Exposure Limit: 2.5 ppm
TWA — 8-hour time-weighted average: 2.5 ppm