I worked at GE Evendale, one of two or three GE plants that built jet engines. There were dozens, if not 100s of de-greaser pits in the factory where a chain hoist was located over a big hole in the floor. If I remember, the opening was about 5' by 5' (with safety railing all around) and perhaps 50 feet deep. And, somewhere in the depths below, there was TCE. You chained a piece of oily/greasy/dirty metal to the hoist, lowered it into the hole, waited a few minutes, and then brought up a nice shiny clean metal part.
You could look down the hole and see a mist swirling below. Evidently TCE vapors are sufficiently heavy that they don't climb out of the pit. Almost like magic. I say almost, since there are all sorts of environmental problems with facilities that used this chemical for de-greasing. I think another one of my employers abandoned use of a pretty large building due to similar soil contamination.
When I added a mister to my PrintNC mill to blow air with a bit of liquid for cutter cooling and lubrication (Minimum Quantity Lubrication or MQL), I was warned to use Ethanol rather than IPA. The rationale is that IPA fumes, if you ingest enough can potentially poison you (like drinking wood alcohol). Ethanol, on the other hand, is denatured Ethyl alcohol. Typically, an added bitterant keeps people from drinking it. However, the bitterant won't harm you and the worst case from breathing the mist in high concentration would be inebriation. I don't know how much of risk there is either way, but I don't use IPA in the mister. But I do use it for cleaning.
You could look down the hole and see a mist swirling below. Evidently TCE vapors are sufficiently heavy that they don't climb out of the pit. Almost like magic. I say almost, since there are all sorts of environmental problems with facilities that used this chemical for de-greasing. I think another one of my employers abandoned use of a pretty large building due to similar soil contamination.
When I added a mister to my PrintNC mill to blow air with a bit of liquid for cutter cooling and lubrication (Minimum Quantity Lubrication or MQL), I was warned to use Ethanol rather than IPA. The rationale is that IPA fumes, if you ingest enough can potentially poison you (like drinking wood alcohol). Ethanol, on the other hand, is denatured Ethyl alcohol. Typically, an added bitterant keeps people from drinking it. However, the bitterant won't harm you and the worst case from breathing the mist in high concentration would be inebriation. I don't know how much of risk there is either way, but I don't use IPA in the mister. But I do use it for cleaning.
