Used antifreeze

Overview

Antifreeze is added to water and other liquids to lower their freezing point. Ethylene glycol is the most common automotive cooling-system antifreeze, although methanol, ethanol, isopropyl alcohol, and propylene glycol are also used. All can be toxic if ingested by animals or humans. Used antifreeze, through contact with a car's cooling system, may contain traces of fuel, oil, and metals (including lead, chromium and cadmium) which make it a potential hazardous waste. Solid and hazardous waste management regulations as well as local municipal wastewater regulations are likely to apply, dependent on how the antifreeze is managed and disposed of. Antifreeze should not be disposed of on the ground or down a storm sewer.

The Wisconsin Department of Natural Resources considers used antifreeze a Wisconsin-specific universal waste if it's recycled. Universal wastes include commonly generated wastes that can be recycled, such as fluorescent lamps, batteries, mercury containing devices and some pesticides.

May used antifreeze be put down drains?

Although it's possible to receive permission from your local publicly owned treatment works (POTW) to dispose used antifreeze to the sanitary sewer, due to the heavy levels of lead and other metals it commonly contains, discharging down drains is NOT recommended as a best management practice.

Other resources

DNR's publication "Managing Used Antifreeze"  (PUB WA-356) summarizes the regulations and requirements that apply to used antifreeze.