To the question about RV antifreeze, that is 50% propylene glycol, 50% water. BTW POLYpropylene glycol would be a solid as the poly means it has polymerized. SIERRA antifreeze which is supposed to safe for dogs to drink is propylene glycol, plus rust inhibitors and seal lubricant. Here is its SDS. https://www.peakhd.com/wp-content/upload...lant.pdf?x38462
