If I had to choose splashing my arm with a concentrated acid, I would choose sulfuric or nitric acid over HF.
Unlike the other acids that just burn the surface of the skin, HF rapidly penetrated the skin and can mess up your potassium levels. Plus tissue destruction is much deeper.
There are some idiots that use open air HF for etching. That is a very bad idea.
I should clarify by open in the description I meant valve open. The system was still closed.
How is that safer than neutral-pressure, aqueous HF? I'm perfectly comfortable with bottled HF, to the point that I literally handled it in the dark (light-sensitive samples), but I'd never set foot in the same room as a pressurized HF gas canister. A spilled HF bottle is a major incident, but ultimately straight forward to contain, whereas an HF canister leak would kill off an entire lab.
I've done enough manifold setups and worked with enough gas cylinders to understand that they can leak in all kinds of ways, even with a wealth of experience. As I said initially: you are definitely not paranoid enough about this setup.
>It’s sold compressed in metal cylinders, like other gases, but it needs some care in packaging. The stuff is so corrosive that special alloys need to be used, usually ones high in nickel. If you stick an ordinary gas regulator on top of an HF cylinder, you’re in for trouble, and the complete destruction of the regulator is the least of your worries.
>HF has actually been used right out of the cylinder for a long time in Merrifield peptide synthesizers.
[1]: https://blogs.sciencemag.org/pipeline/archives/2004/03/03/th...
I was speaking more generally. It’s not uncommon for labs to handle concentrated HF in a similar manner as other acids - I.e. pouring it into a beaker in a fume hood
And I was clear that setup matters in my gp.