- Chemical name
- Ethylene glycol / ethane-1,2-diol
- CAS number
- 107-21-1
- Formula
- C2H6O2
- Also known as
- Monoethylene glycol, MEG
Ethylene glycol, coolant and antifreeze
Ethylene glycol is used in antifreeze and cooling applications and as a chemical feedstock. Commercial coolant can also contain water, corrosion inhibitors, dyes and other ingredients. Once used, it may contain further contamination from the engine, circuit or industrial system in which it circulated.
Coolant colour is not a reliable way to identify glycol type. Ethylene glycol and propylene glycol are different substances, so the product label, safety data sheet or maintenance record is a better basis for identification than colour alone.
Used coolant and contamination
Waste from an engine, heating circuit, cooling system, surplus product store or industrial process can have different contamination profiles. Oil, metals, cleaning additives or mixing with another coolant can affect classification and the available recovery or treatment route.
Known unused stock should be kept distinct in the waste description from recovered or mixed coolant. Analysis may be needed when the formulation or later contamination is uncertain. Appearance alone does not show that used coolant is suitable for reuse, recovery or discharge.
Recovery, treatment and disposal
Suitable glycol-bearing liquids may be assessed for recovery or treatment. Glycol concentration, additives and contaminants affect facility acceptance. The description “antifreeze” does not establish a waste code or receiving route without the waste source and underlying composition.
Used coolant requires an authorised waste route unless a separate lawful discharge route applies to that specific liquid. Correct identification and sound containers remain important because ethylene glycol is harmful if swallowed, and mixing it with unrelated workshop wastes can make classification and treatment more difficult.
Describing used glycol and coolant
The assessment should identify the coolant brand, glycol type, approximate concentration, system use and known contamination. Quantity and whether the liquid is contained or remains in equipment also affect removal and assessment alongside any oily residues or contaminated packaging.