Hydrofluoric acid (HF) ­ A clear, corrosive liquid that has an extremely pungent odor and forms dense white vapor clouds if released. Both the liquid and the vapor can cause severe burns to all parts of the body, and medical treatment is required for all exposures. In fact, HF burns covering only 2% of the body can be fatal. If this chemical comes in contact with glass, concrete and other silicon-containing materials, it yields silicon tetrafluoride gas. If it comes into contact with common metals, it will produce hydrogen fluoride, which poses a fire and explosion hazard. In general, this chemical is used to produce environmentally safer fluorocarbon products, chemical derivatives, and fluoropolymers. Environmentally speaking, hydrofluoric acid is much too reactive to ever reach the upper atmosphere, and would not interfere with the ozone layer.
[Chemical Week, v 164(45); 2002; 35] [Chemical Market Reporter, v 262(12); 2002; 31] 
Atmospheric Chemistry Glossary