That might be true of the older solvent-based PCB cleaners, but the
stuff we've been given for use with this one is water based and
basically just a really strong detergent. You should certainly not be
drinking it and it's important to avoid prolonged contact with the
concentrate or getting it in your eyes, but the made-up solution is not
much worse than strong washing up liquid.
You'll certainly want to keep it out of your eyes so goggles never hurt,
and prolonged skin contact is likely to result in irritation but so long
as it's promptly washed off you shouldn't expect any problems, it's not
a known carcinogen. I'll get hold of the MSDS for it and shove it up on
the wiki later.
Steve