The liquid, which the Palo Alto Fire Department has deemed to be a nonhazardous mixture of borax, lye (also called sodium hydroxide) and green dye, spilled out of the Tesla office at 1501 Page Mill Road onto Hanover Street.
You don't want concentrated lye, but diluted lye is safe enough to make soap. My question, and I'm not the only one asking in this thread, is- is a mixture of borax and lye a good coolant for a supercomputer?
I guess you could argue that the green is so they would recognize a coolant leak...
Borax is used for flushing large coolant systems. The green dye is probably to find leaks or identify when the flush has cleared out any residual coolant.
The lye concentration used to make soap is rather nasty if it gets on your skin and you don't deal with it immediately.
Source: I've made a lot of soap from scratch.