Keep Pets Safe When Preparing Household for Colder Weather

[dog in the snow]

A typical garage holds many hazards

Cold weather is here. It’s time to winterize the car, pull out the space heaters, and thwart invading rodents. For pet owners, however, these common seasonal activities should be approached with caution because of the potential for hazardous outcomes for pets.

Dr. Michael Biehl, a veterinary toxicologist at the University of Illinois College of Veterinary Medicine in Urbana, offers advice on how to keep pets safe.

Dogs that spend the summer months outside may be moved to the garage when temperatures drop. Dr. Biehl points out that there are many hazards in a typical garage that will require “pet proofing” before it is ready for Fido.


Antifreeze has a sweet taste that attracts pets (and children), but its main component is ethylene glycol, which is highly toxic and potentially fatal. According to Dr. Biehl, any amount of exposure should be considered serious.

“Primary signs associated with ethylene glycol toxicity include loss of coordination, lethargy, vomiting, and an increase in urination and heart rate. The last stage of this toxicity is kidney failure and death,” says Dr. Biehl.

If an animal may have ingested antifreeze, it is important to seek veterinary care as soon as possible so the proper course of treatment can be administered. Also note that alternative “safe” antifreeze products are now on the market that contain propylene glycol instead of ethylene glycol.

For questions regarding how to properly dispose of antifreeze, call your local sewage treatment plant to determine local regulations regarding disposal in the sewage system. Another option is to take antifreeze to an automotive shop for disposal, as they collect large amounts they have specific disposal regulations and practices, although they may charge a disposal fee.

Carbon Monoxide

Propane or kerosene space heaters can also pose a threat to animals that are confined to a garage. If these heaters are not working properly, or are placed too close to a wall such that they do not have proper ventilation, they may release carbon monoxide, a deadly gas that is colorless and odorless. They should be used only in a room that is well ventilated, never in a closed garage.

An animal exposed to carbon monoxide in a confined space will exhibit drowsiness, weakness, and a lack of coordination. Treatment includes getting the animal to a well-ventilated area and providing oxygen. If treatment is not administered quickly, the animal will fall into a coma and eventually die.

Pets and people are not the only creatures that want to come indoors when it gets cold. Mice and other rodents are also seeking a warm shelter, which leads some homeowners to put out poisons.


Unfortunately, dogs and cats regularly find the rodent bait, which typically contains bromethalin (a neurotoxin), cholecalciferol, or various types of anticoagulants. Anticoagulant rodenticides work by inhibiting the blood clotting mechanism so animals eventually die of internal bleeding. Cholecalciferol ingestion results in elevated concentrations of calcium in the blood, which causes many problems. And as little as two teaspoons of bromethalin is toxic to a 25-pound dog, while the fatal dose for cats is half of that for dogs.

“Acute signs of bromethalin toxicity include agitation, uncoordination or paralysis, tremors, seizures, and death,” says Dr. Biehl. “An animal that survives the first 24 hours may linger up to five more days in the chronic phase with flexed forelimbs, rigid hind limbs, and terminal seizures.”

“The bottom line is, an animal that may have gotten into rodent bait should immediately be taken to see a veterinarian,” says Dr. Biehl. “It’s extremely important to bring the packaging of the rodenticide and to note the approximate time and amount that the pet has eaten. This information will help the veterinarian determine the rodenticide involved and appropriate course of treatment.”

Luckily, avoiding these potential hazards can be as simple as keeping the antifreeze and rodenticide on a top shelf or in a closed cabinet and avoiding animal exposures when using it, using properly working propane/kerosene heaters only in well-ventilated areas, and using humane mouse traps instead of rodenticides.

For more information about animal toxicants, or if you think your pet may have ingested something toxic, contact your veterinarian or the ASPCA Animal Poison Control Center at 888-426-4435.

By Sarah Netherton