Antifreeze: What Makes It Unsafe for Animals?

Antifreeze is necessary for the safe and proper operation of your vehicle, but even a teaspoon of the toxic chemical can prove fatal for your pets. Antifreeze is used in the radiators of cars, trucks, tractors, and other motor vehicles to prevent overheating in the summer and freezing over in the winter.

Ethylene glycol is the ingredient used in antifreeze that makes the product deadly to both humans and animals. Ingestion of even a small amount is enough to cause severe medical distress, and even death, in the average sized cat, small dogs, and other wildlife. American figures estimate that between 10,000 and 90,000 animals are poisoned each year. Nearly 88% of animals that come in contact with antifreeze do not survive.

If you suspect that your pet has been poisoned by antifreeze, it is important to take the animal to a veterinarian immediately. Any delay in medical attention greatly diminishes your pet’s chance of survival. “Vomiting typically develops rapidly after ingestion and at this point the animal may also show signs of depression, incoordination, weakness, and faster than normal breathing; as well, they may be drinking a lot, and urinating more than usual,” explains Dr. Sandra Neumann president of the Saskatchewan SPCA Board of Directors. “The animal may seem better for a couple of hours before there is a swift decline in health, six to 12 hours post-ingestion. It can cause kidney failure in cats as soon as 12 hours after exposure,” advises Neumann.

Although some antifreeze is made with propylene glycol, it is not safe for animals either. “It is about three times less toxic in dogs than ethylene glycol, but can also cause signs of toxicity like depression, weakness, incoordination, and seizures if ingested in larger quantities. It can also cause liver failure and kidney insufficiency,” warns Dr. Neumann.

In an attempt to make the antifreeze less palatable, the addition of a bittering agent, such as denatonium benzoate, to the antifreeze may deter animals from consuming the noxious substance. However, even with the bittering agent, the toxicity of the antifreeze is unchanged. According to Dr. Neumann, “There is no real safe antifreeze out there,” recommending it’s best to avoid all types of antifreeze. Dr. Neumann concludes the addition of the bittering agent may be “the best way to go.”

Steps are being taken by governments and manufacturers to insure animal safety. In 2009, the Government of British Columbia passed a regulation requiring the addition of a bittering agent to all antifreeze sold to B.C. consumers. Although it is a movement in the right direction, this regulation does not require service stations and automotive repair businesses to use the embittered antifreeze. Since the auto service industry is the largest user of antifreeze, the majority of antifreeze used in the province’s vehicles does not contain the bittering agent. In the United States, all antifreeze manufacturers have voluntarily agreed to add the bittering agent to their antifreeze products.

Options are available for those in need of antifreeze disposal services. The Saskatchewan Association for Resource Recovery Corporation (SARRC) has a network of 200 collection facilities and eco-centres throughout the province that operate year-round. SARRC collects old antifreeze, used oil, filters, and oil, antifreeze, and diesel exhaust containers. Information on SARRC’s collection facilities and guidelines can be found at

The prevention of antifreeze poisoning begins at home. Be diligent in the proper disposal of old antifreeze products, including empty containers. Clean up any antifreeze spills using the appropriate equipment and materials. Avoid pouring old antifreeze down storm drains, sinks, toilets, or on the ground. Educate your family and friends on the dangers of antifreeze. Following these suggestions will help safeguard your pets from the disastrous effects of antifreeze poisoning while sparing your family from mourning the loss of a beloved companion.

Note: Image above is simulated.