A formulation of 94.0 percent propylene glycol and a specially designed package of industrial corrosion inhibitors. The fluid is dyed fluorescent yellow-green for leak detection purposes. Solutions of this in water provide freeze protection to below -50°C (-60°F) and burst protection to below -73°C (-100°F). It is widely used within the HVAC industry or wherever low toxicity, environmentally heat transfer fluids are needed.