The family of DOWFROST heat transfer fluids are made with DOW PuraGuard™ Propylene Glycol USP/EP, a pharmaceutical grade of monopropylene glycol with specified purity greater than 99.8% and can be formulated with food grade corrosion inhibitors, as is the case for regular DOWFROST, to allow the use in applications where contact with food or beverage products could occur. For non-food processing applications, DOWFROST HD which contains supplemental, non-food grade additives can be used and is capable of operating at higher temperature and more stressful conditions. .