Last November, I wrote a two part post about the danger that ethylene glycol containing antifreeze poses to pets and talked a little about "animal-friendly" antifreezes that contain a bittering agent (denatonium benzoate) to make them taste bad. I’ve got good news! On December 13, the Humane Society Legislative Fund (HSLF) and Consumer Specialty Products Association (CSPA) jointly announced an agreement to voluntarily add a bitter flavoring agent to antifreeze and engine coolant manufactured for sale for the consumer market in all 50 states and the District of Columbia.

Seventeen states (Arizona, California, Georgia, Illinois, Maine, Maryland, Massachusetts, New Jersey, New Mexico, Oregon, Tennessee, Utah, Vermont, Virginia, Washington, West Virginia and Wisconsin) had previously passed laws mandating the inclusion of a bittering agent in antifreeze, but multiple attempts to pass a federal law had failed. The HSLF estimates that between 10,000 and 90,000 animals are poisoned each year after ingesting ethylene glycol in antifreeze and engine coolant.

The CSPA is a trade association that represents the interests of companies that manufacture, formulate, distribute, and/or sell consumer products like disinfectants, air fresheners, cleansers, and of course, antifreeze. In a press release, Phil Klein of the CSPA says, "Partnering with the Humane Society Legislative Fund in passing these laws in 17 states has shown by finding compromise and working together we can develop sound public policy. It is vital that consumers continue to read the labels and follow label instructions on the proper use, storage and disposal of antifreeze. Today, all major marketers are placing the bitterant in antifreeze in all 50 states."

This brings up an important point. The inclusion of denatonium benzoate in antifreeze does not mean it is now safe for pets, wildlife, or children. Denatonium benzoate simple makes the mixture taste bitter instead of sweet. Denatonium benzoate is the same ingredient that is used in products used to deter nail biting and thumb sucking in people and licking and chewing in pets, and those products are hardly 100 percent successful. Veterinarians who practice in states where bittering agents are mandated do still report seeing pets suffering from ethylene glycol poisoning, but it’s difficult to say whether they are getting into local antifreeze or that which is coming in from across state lines.

So if you are aware of an antifreeze spill, you’ll still want to clean it up well: soak up the liquid with kitty litter, safely dispose of the mixture, and rinse the area with copious amounts of water. I suspect the addition of denatonium benzoate will save a lot of lives, even if some individuals (I’m thinking mostly those dogs that will seemingly eat anything) do continue to get sick.

Ultimately, the best way forward is probably for us all to switch to propylene glycol versus ethylene glycol based antifreezes. This option is more expensive though, so I doubt it will happen anytime soon. Just look how long it took to get manufacturers to add three cents worth of denatonium benzoate to conventional antifreeze.

Dr. Jennifer Coates

Image: Valeriy Velikov / via Shutterstock