A cat walks through winter snow

Antifreeze is very toxic for your pet

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The danger of antifreeze on pets

By Nick Whittle Author

Updated on the

Winter is approaching and like many, you will probably prepare your car to this cold season, this includes adding antifreeze in your car. Be extra vigilant, keep this product out of reach of pets as it is very toxic for them.

Ethylene Glycol is the main component of most antifreeze. It accounts for at least 95% of the product’s active ingredients. EG is a clear and sweet liquid. It is used in other products besides antifreeze, but here we are concerned about its use as antifreeze, and about what danger (if any) it poses to cats and dogs. 

On account of its sweet taste, antifreeze is something a cat may be drawn to, but dogs too have been known to drink it. Due to this product being an alcohol, EG has an endothermic effect on the drinker, which tempts animals to drink it on very cold days. Cats are more likely than dogs to come across antifreeze because they are allowed to wander by themselves outdoors.

The minimum lethal dose of antifreeze for a cat is about 3mls per pound body weight. That equates to a very small amount: about half the contents of a normal-sized syringe. Fast treatment is essential in order to save a pet from serious ethylene glycol poisoning.

Is RV antifreeze harmful to pets?

RV antifreeze is, according to its manufacturers, ‘non-toxic’. But that is not to say that it won’t cause your pet harm.

It is thought to be harmless because it contains three substances in different non-lethal measures. 

  • Ethanol 
  • Ethanol and Propylene 
  • Propylene Glycol

Ethanol, Propylene and Propylene Glycol

Ethanol and a blend of Ethanol and Propylene are exceptionally toxic to humans and animals, but Propylene Glycol is less so. PG is considered non-toxic to humans (it is a primary ingredient of vape liquid).

It is also considered less toxic to animals, but that is not to say that it may not kill an animal if present in a big enough quantity.

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If a cat (or dog) drank enough RV antifreeze they would certainly be poorly, and would require urgent veterinary treatment. However, if they were to drink just a small amount they may not be as poorly as they gulped traditional antifreeze.

Is modern antifreeze toxic?

Modern antifreeze has as its primary ingredient Ethylene Glycol. That makes it a deadly liquid if ingested. EG antifreeze is the most common type of antifreeze sold. 

According to Dr Sarah Steinbach of Purdue University College of Veterinary Medicine, the majority of antifreeze poisonings occur in the winter. 

She told, “As it gets colder and colder, we will see more and more cases of ethylene glycol poisoning, unfortunately.

“Pets who have ingested the liquid may present as if they were intoxicated because ethylene glycol is an alcohol.”

However, it is not the EG itself that is the culprit in cases of animal poisoning. According to Dr Steinbach, it is the metabolizing of the alcohol within the body that causes toxicosis, and leads rapidly to severe kidney damage.

Within 8-12 hours of ingestion a dog or cat may appear “hyperactive or lethargic, nauseous and wobbly,” says Dr Steinbach, and such signs of poisoning must not be ignored.

Is antifreeze harmful to skin?

Antifreeze is not especially harmful when it contacts skin. To wash the affected area with soap and water should alleviate any reaction to the alcohol.

What happens if you sniff antifreeze?

Ethylene Glycol vaporises very easily. It is harmful to humans and other animals if inhaled, and long-term exposure should be avoided. Our use of antifreeze must be restricted to the outdoors. Excessive inhaling of antifreeze causes us and our pets to experience breathing difficulties.

If inhaled in sufficient qualities EG may even cause brain damage.

How long does antifreeze stay in the ground?

Ethylene Glycol on the ground and in the open air will stay viable for around 10 days. But in water and soil it may still be present after several weeks.

Antifreeze containing EG should be disposed of according to the directions shown on the label.

Is it safe to taste antifreeze?

To drink even a small amount of antifreeze is highly dangerous. Furthermore, the initial effects of ingestion are only the beginning of a very painful experience that could result in death.

Some manufactures in the United States have started to add a bittering agent to their antifreeze products in order to deter people and animals. However, recent research has proved bittering agents to be unsuccessful in the prevention of most cat and dog poisonings.

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What antifreeze is safe for pets?

In short there is no such thing as antifreeze that is safe for pets. Even small amounts of antifreeze ingested can be fatal to small animals. As an example, if a cat licks its paws after walking through a puddle of antifreeze it will become poorly.

According to some scientists, around five tablespoons of EG antifreeze can kill a cat or medium-sized dog within 12 hours.

The signs of antifreeze poisoning take some time to become apparent. In the first few hours of ingestion your pet may appear listless and dizzy; they may also drink lots of water. The true signs of toxicosis may not show until one or two days after ingestion, by which point kidney failure has set in and the prognosis is poor.

What can be used in place of antifreeze?

You may use tap water as a temporary coolant but such use is not recommended due to the fact that it does not prevent mechanical rusting and corrosion. There are unfortunately very few products that can beat EG antifreeze for its positive effects and prevention of engine problems in cold weather.

With EG antifreeze more-or-less the sole marketed antifreeze, alternatives are slow to come forward, and current alternatives appear less effective at protecting vehicle engines and other machinery from frost damage. Thus, the onus is on the owner to ensure their pet does not come to harm.

The risk of a cat’s poisoning far outweighs that of a dog, and so it is imperative that owners of cats take responsible steps to ensure their pets cannot come into contact with noxious substances. Allowing a cat out on its own will always carry associated risks, but these can be mitigated to an extent by monitoring the animal closely on its return. 

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