There is an article on HF hazard potential which I could not believe about its extent. What I know is that, if HF comes in contact with skin, it can cause burns, nasal rupture if inhaled, punctures and penetrates through the bone. But, the article mentions about its distance of impact of 2 miles from the source when travels as a cloud.
HF is used a catalyst in refineries to make high octane gasoline, as mentioned in the article. The IDLH is 30 ppm and it was found at 2 miles distance when 1000 gal was released from tanker containing 5000 gal at a pressure and temperature as used in refineries. The HF travelled as vapour and mist and needed 40 parts of water for every part of HF to dilute it, though the officials doing the experiment thought that it will remain as a liquid and can be contained. The article also mentioned about use of an additive to make HF less dangerous by way reducing its ability to form vapour cloud.
Few years ago, I read an article in the internet, in which a college girl died because of HF. When she was doing experiment, few HF drops splashed on her lab coat. She washed it with water for sometime and continued her lab work. She was found dead by her neighbours, the next day. The reason mentioned is that the vapour from lab coat was inhaled by the girl and this lead to oedema.
In a book on Bhopal accident, I read that few years before, in the same plant a similar death occurred from phosgene splash on the body. Here, the lesson is that we should not be complacent and assume that by washing for a minutes, the chemical can be cleaned. Once some chemical splashes, we should takeout the clothing. This should be followed with water wash.
Normally, as a safety precaution, one should wash for at least 15 minutes once any chemical splashes/falls on the body. Even then, studies show that only about 95% of the chemical on the skin can be washed off. During my safety lectures, I tell my audience that during the beginning of every shift, atleast once, they should check for availability of water in emergency shower/eye wash fountain and allow the water to run for few minutes so that any dirt/rust collected can run off. Else, the damage from this dirty water may be more than that from the chemical splash.