I'm not sure the colour is as consistent as it should be, so to be sure the old-type stuff is Ethylene Glycol, with no OAT. Ethylene Glycol is normally blue, and on the back of the bottle I've got here it's also labelled "Ethanediol" as an alternative name.
This is the stuff that's pretty toxic and smells yummy to animals, so be careful and don't spill it or leave it out.
It's frequently mixed with Di-Hydrogen Monoxide.