Mitco’s Propylene Glycol is non-corrosive and safe for closed systems where potable water exists. It is a heat transfer solution for use on hydronic, heat pump and solar heating systems. Product will not separate and leave deposits on heat transfer surfaces. Its lubricating qualities extend component life. Provides burst and freeze protection at temperatures as LOW as -100°F  depending on PG% (see chart on bottom of page). All ingredients used are generally recognized as SAFE (GRAS).