Ethylene glycol is found in a wide range of products, from the antifreeze in your garage to the plastic water bottle on your desk. It is most concentrated in automotive and industrial products, but it also shows up in inks, paints, solvents, and de-icing fluids. Because ethylene glycol is toxic when swallowed, knowing where it hides matters, especially in households with children or pets.
Automotive Products
The most familiar source of ethylene glycol is engine antifreeze and coolant. A standard antifreeze product is mixed 50/50 with distilled water, which protects engines from freezing down to -34°F and from boiling up to 265°F. Manufacturers recommend keeping the ethylene glycol concentration between 40% and 60% for proper engine protection. Hydraulic brake fluid is another automotive product that commonly contains it.
These products are the leading cause of accidental ethylene glycol poisoning in both humans and animals. Antifreeze has a bright color (often green or orange) and a sweet taste, which makes it attractive to children and pets. Even a small amount can be dangerous: the estimated lethal dose in humans is roughly 1,400 to 1,600 mg per kilogram of body weight, and for a small dog or cat, far less can be fatal.
Household Items
Ethylene glycol turns up in products you might not suspect. According to the CDC, it can be found in certain stamp pad inks, ballpoint pens, paints, coatings, and general-purpose solvents. The concentrations in these products are much lower than in antifreeze, but they’re worth knowing about if you have young children who might chew on pens or get into craft supplies.
Some household cleaners and degreasers also contain small amounts. If you’re trying to identify whether a specific product in your home contains ethylene glycol, the Safety Data Sheet (SDS) that manufacturers are required to provide will list it as an ingredient.
Plastics and Polyester
Ethylene glycol is a key building block of PET plastic, the material used for water bottles, food containers, and polyester clothing. During manufacturing, ethylene glycol reacts with another chemical to form the polymer chains that make up PET. The ethylene glycol itself is consumed in the reaction and doesn’t remain in the finished product in its original toxic form, so drinking from a PET bottle is not an exposure risk.
This industrial use actually accounts for the largest share of global ethylene glycol production. Billions of pounds are consumed each year to make polyester fibers for textiles and PET resin for packaging.
De-Icing Fluids
Airports use large volumes of ethylene glycol-based fluid to de-ice aircraft and runways. These fluids are typically mixed at about 50% glycol concentration, and the EPA estimates that 21 million gallons of de-icing fluid at that concentration are discharged into surface waters annually from U.S. airport operations alone. The environmental runoff is significant enough that the EPA has issued specific guidance on managing it to protect drinking water sources.
It’s worth noting that some de-icing operations, particularly for aircraft surfaces, have shifted toward propylene glycol, a much less toxic alternative. Propylene glycol is also what you’ll find in many consumer-grade antifreeze products sold at supermarkets. However, ethylene glycol remains common in runway de-icing and in closed industrial systems where human contact is unlikely.
Solar Energy Systems
Solar thermal panels, the kind that heat water rather than generate electricity, often use ethylene glycol as a heat-transfer fluid. It circulates through the panels and transfers captured heat to a water tank. The glycol prevents the system from freezing in cold climates and handles high temperatures better than water alone. These are closed-loop systems, so the fluid doesn’t come into contact with your household water supply under normal conditions.
What About Cosmetics and Personal Care?
You may see ingredients with similar names on cosmetic labels, but ethylene glycol itself is not the same as polyethylene glycol (PEG). PEG is a polymer derived from ethylene glycol, but it behaves very differently in the body. It has low toxicity, dissolves easily in water, and helps skin retain moisture. PEG compounds appear in lotions, creams, and pharmaceuticals and are considered safe for those uses.
Ethylene glycol does appear in some industrial-grade coatings and cosmetic manufacturing processes, but finished consumer skincare products overwhelmingly use PEG instead. If an ingredient list shows “PEG” followed by a number (like PEG 200 or PEG 8000), that’s the safer polymer, not ethylene glycol.
How Ethylene Glycol Causes Harm
Ethylene glycol itself isn’t the most dangerous part. The real damage comes from what your body turns it into. Your liver breaks ethylene glycol down through several steps, eventually producing a compound called oxalate. Oxalate binds to calcium and forms tiny crystals that deposit in the kidneys, which is the hallmark of ethylene glycol poisoning and the reason kidney failure is the most serious outcome.
Ingestion of as little as 150 mL (roughly half a cup) has been associated with fatal outcomes, though reported lethal amounts range up to 1,500 mL depending on the individual and how quickly treatment begins. The initial symptoms, including nausea, confusion, and what looks like drunkenness, can make poisoning easy to miss in the first few hours.
Safer Alternatives
Propylene glycol can replace ethylene glycol in many applications. It offers much lower toxicity, which is why it’s approved for use in food processing, cosmetics, and medications. The tradeoff is performance: ethylene glycol depresses freezing points more effectively and transfers heat better, so you need more propylene glycol to achieve the same protection level. It also has higher viscosity, which makes it slightly less efficient in some systems.
For home use, propylene glycol-based antifreeze is the safer choice if you have pets or children. In closed industrial loops where there’s no risk of contact with food or drinking water, ethylene glycol remains the standard because of its superior thermal properties and lower cost.