Econo Plumbing Antifreeze provides burst protection down to -50 degrees C when used neat. It has been specially formulated to protect and prevent damage caused by freezing in drains and fresh water lines in septic systems, boats, recreational vehicles, seasonal homes, as well as filtration and heating systems of swimming pools. It is safe for plastic pipes only. Plumbing antifreeze is a mixture of propylene glycol, alcohols and water. It is completely non-toxic and, if used as directed, is not harmful to the environment.