Many moons ago, when I was a spry young apprentice, I worked for this old German Master in a steel fab shop. The building was a steel structure, with tin walls. No insulation, pidgeons were constantly flying inside, etc. Might as well have been working outside, except that you didn't get rained on as there was a roof over your head.
Well winter would come and although it rarely froze in the Burnaby / Vancouver area, once in a while it would. So as the temperatures dropped, even though it did not freeze, it still got mighty cold, the occasional time the temp would plumment and the bandsaw and cold cut saw coolant, basicaly water soluble cutting oil, or milk as it was commonly called would start to freeze up. So we added a bit of antifreeze to the cutting fluid to keep it liquid and then if it got really cold and water stopped running from frozen pipes, out would come an old blast furnace, hook that up to natural gas and light it up. That took the chill off the air, sort of. Then Walter had to play plumber and repair any cracked water pipes that had split from the freezing.
So yes, I have used antifreeeze in water soluble cutting fluid.
Walter