The bit about buying propylene glycol rather than ethylene glycol antifreeze is good advice, but it's still toxic, just not as bad. I mention this because propylene glycol is present in many homes in another form.
It is the base for most e-liquids used in electronic cigarettes, and the nicotine is also bad for cats. I have several bottles of the stuff, which I've had to put away, as they make good cat toys. A loose lid, or a vigorous playtime with sharp teeth could result in a very unhealthy drink for the cat.
