I was a master optician for the first half of my work life and we used HF to etch glass. One woman I worked with was soaking some lenses in it and had a hole in her protective apron and it soaked her belly. She was out for weeks and retired later that year due to on-going pain in her bones(I caught her cleaning our trichloroethane degreaser once while smoking a cigarette so not the sharpest glass shard in the pile). When I moved into field service, our systems used lasers that used florine gas. One day some idiot in facilities broke one of the lines feeding a laser and Florine gas flowed into the subfab. When the gas gets into your lungs where it is nice and moist, it forms hydrofloric acid. Several people had to go to the ER for that. That being said, I was joking about using it in my home much less my grow...