Antifreeze containing propylene glycol is far less toxic than ethylene glycol antifreeze, so it is less likely to cause fatal poisoning of pets or people.
Vehicles require antifreeze to prevent engines from freezing during winter and over-heating in the summertime. Unfortunately, the commonly used ethylene glycol antifreeze products are extremely toxic to pets, but their sweet taste encourages pets (and in some cases, children) to ingest them voluntarily. Pets may also ingest antifreeze that they have stepped in while grooming their feet.
A cat may die after ingesting a single teaspoon of antifreeze, and a 10-pound dog can be killed by as little as a tablespoon of the substance. Up to 88% of all animals that ingest antifreeze die.
Ethylene Glycol Antifreeze Kills Thousands of Pets Each Year
Each year, an estimated 10,000 companion animals die as a result of antifreeze poisoning, and this number does not include wildlife or human poisonings (accidents, suicides, and murders).
Pets and wildlife often die due to accidental antifreeze poisoning when antifreeze containers are left open or when antifreeze leaks from vehicles or is spilled during careless fluid changes. Also, there have been cases of pets deliberately poisoned by sadistic individuals.
Propylene Glycol Antifreeze Is Far Less Toxic (and Less Tasty)
Ideally, consumers should purchase the far less toxic propylene glycol antifreeze products. Propylene glycol products are biodegradable, anti-corrosive, and recyclable.
Propylene glycol antifreeze products are more environmentally friendly, and in addition to being less likely to cause fatal poisoning, they don’t taste like candy the way ethylene glycol products do, so pets and children are far less likely to consume them.
In April 1, 2009, a new British Columbia regulation, the first of its kind in Canada, required that ethylene glycol antifreeze products contain a bittering agent, denatonium benzoate, to make them less appealing to children and animals. The new regulation was scheduled to take effect in 2011. Similar regulations have been put in place in a number of U.S. states.
However, given that ethylene-glycol-based antifreeze is the more toxic product, many feel that adding a bittering agent is not sufficient. Critics of the measure would like to see ethylene glycol products banned altogether so that only the less toxic (and less tasty) propylene glycol products are available.
Concerns that have been raised regarding the use of the bittering agent with ethylene glycol antifreeze include the following:
- It may not deter animals from consuming antifreeze.
- Even if animals are deterred from voluntary ingestion, they may still lick it off their paws.
- The bittering agent may get into drinking waters supplies – just a tiny amount would make drinking water unpalatable.
- Denatonium benzoate is not easily biodegradable, and its potential long-term environmental impacts are unknown.
- Adding denatonium benzoate may shield antifreeze makers from liability for environmental toxicity and damage.
- Allowing the use of a bittering agent reduces the likelihood of making the switch to a less-toxic, more environmentally friendly alternative.
How to Prevent Antifreeze Poisoning
Antifreeze takes weeks or even months to biodegrade on its own and if poured out on the ground, can contaminate both earth and water. To reduce the risk of antifreeze poisoning:
- Store antifreeze out of reach in tightly sealed containers – never transfer it to food or drink containers, as people have been poisoned this way.
- Repair leaks and mop up antifreeze spills immediately – use absorbent material such as rags or kitty litter rather than water, as hosing the area down will create contaminated wastewater. The area can be scrubbed with a little soap and water afterward if necessary, though all this fluid should be soaked up with absorbent material as well.
- Dispose of antifreeze properly at an auto center that recycles it – never pour it down storm drains, toilets, sinks, etc.
- Supervise pets in garages and other areas where there may be antifreeze spills or open or leaky containers.
- Never leave open containers of antifreeze unattended.
- Keep cats indoors, and make sure outdoor pets have sufficient drinking water – free-roaming pets, and particularly thirsty pets seeking sources of fluid, are particularly vulnerable to poisoning.
- Avoid keeping decorative snow globes within reach of pets or unsupervised children – their liquid contains antifreeze, so if the glass breaks, pets and children could be exposed to the toxin.
Symptoms of Antifreeze Poisoning in Pets
The initial symptoms of antifreeze poisoning, which appear 30 minutes to an hour after ingestion and may last for a number of hours, include:
- Lack of coordination
Animals may appear to be drunk during the first phase of the poisoning. The second phase of poisoning, lasting up to several days, has symptoms that include:
- Oral and gastric ulcers
- Kidney failure
Anyone who suspects that a pet has ingested antifreeze should seek emergency veterinary care immediately. The faster care is received, the greater the chances of survival.
- British Columbia SPCA. (n.d.). “A Bitter Pill: Antifreeze Update” and “Antifreeze Is Deadly to Pets and Wild Animals.” SPCA.bc.ca.
- Emerson Animal Hospital. (n.d.). “Antifreeze Poisoning.” EmersonAnimalHospital.com.
- Hogue, C. (31 July, 2006). “Safer Antifreeze Bill Is Moving Fast.” Chemical and Engineering News, 84(31), pp. 39-41, pubs.acs.org.
- National Capital Poison Center. (Winter 2007). “Antifreeze: Good for Your Car, Bad for Your Kids and Pets.” The Poison Post, Poison.org.
- Simmons, R., New Brunswick SPCA. (2007). “Fatal Attraction: Antifreeze Is a Sweet but Deadly Poison for Pets.” SPCA-nb.ca.