Pets Carbon Monoxide Poisoning is a Thing

Pets carbon monoxide poisoning is an actual thing. Stories of dogs awakening their owners during a fire or gas leak make feel good news stories. However, many people believe that a dog can also detect carbon monoxide and thus act as an alarm system. But just as we humans cannot smell or detect carbon monoxide, dogs and other pets are also unable to detect carbon monoxide. Carbon monoxide is odorless and simply cannot be not detected by any of our pets.

However, that doesn’t mean that pets can’t warn people about carbon monoxide because they can smell things that we can’t, even if it isn’t CO they are smelling. Carbon monoxide forms in a fuel burning appliance because the carbon fuel (natural gas) isn’t completely combusted or burned. This is called incomplete combustion. While pets can’t smell CO, they can smell the other products of incomplete combustion. Another term for the products of incomplete combustion is SMOKE. The pets are smelling smoke, but in quantities too small for human nose to detect to it.

In our experience testing countless furnaces, the human nose will begin to detect smoke when the CO in the exhaust of a furnace gets to levels above 6,000 ppm. A dog can likely smell it when it is a fraction of that level.

Pets Carbon Monoxide Poisoning – An Imperfect Warning

In addition, our pets may act as warning systems due to the fact that they are smaller and have faster respiratory rates than we do. Because of this they may exhibit the symptoms of carbon monoxide poisoning before we do. Some of the symptoms they may exhibit are similar to the symptoms humans display, but there are some symptoms which can point to lethal levels of carbon monoxide in the home.

Pets Carbon Monoxide Poisoning

Pets Carbon Monoxide Poisoning is an actual thing, not a myth. Pets may smell smoke before humans and they are likely to be sick at lower levels.


When we consider size as a factor, smaller animals will react faster and they may perish suddenly with little warning. There are countless stories of the sudden deaths of pet birds alerting families to the presence of carbon monoxide.

Pets Carbon Monoxide Poisoning – A Recurring Story

One such story occurred in Illinois in 2000 right after Christmas. The children were playing while their pet parakeets sang happily nearby.  The family suddenly noticed one bird had died and the other one was struggling and succumbed shortly after. The heartbroken kids were burying their pets when a neighbor suggested that the symptoms sounded very much like carbon monoxide poisoning. The mother called 911 and it was discovered that a slow leak had developed near their furnace blower in the basement and  carbon monoxide has entered the air ducts and filled the dining room near where the children were playing and the birds were located.

In this instance there were carbon monoxide detectors installed in the home which did not alarm. And this suggested that placement of the alarms was an issue in this incident. The mother said that she has since learned that it is a good idea to move alarms around in your home to test carbon monoxide levels in different areas and to also replace older detectors with those with more precise monitors.

Ill Pets Should not be Ignored

The key fact in this case is that multiple healthy pets suddenly perished without explanation. This is common with smaller pets who succumb to carbon monoxide poisoning.

The cliché about the canary in the coal mine meaning the early warning of something, has its origins is that canaries were used in coal mines to warn humans of toxic gases.

Birds have a very unique respiratory system and are highly sensitive to carbon monoxide. Rodents, such as mice, can tolerate twice that amount. Rabbits react very similarly to dogs and cats, sometimes becoming very manic and uncoordinated in the early stages of carbon monoxide poisoning. Reptiles have a very efficient respiratory system, slow metabolic rates and can potentially tolerate periods of time without oxygen. Many exotic pets like spiders have variable needs for oxygen depending on when they ate and their metabolic rate.

What Airs is Your Pet Breathing?

Because carbon monoxide tends to disperse in a room, the location of the pet is not a big factor. The bird hanging in a cage is equally as susceptible as a pet at floor level.

Dogs also can be indicators that there is carbon monoxide present. They may suddenly exhibit anxiety or aggression. They may refuse to enter the house after being outside. They may vomit and appear uncoordinated or become less responsive and appear to have difficulty breathing. Dogs may also have seizures. But a much more alarming symptom is if your dog appears to have bright red lips, gums, ears or skin. This is a sign that your dog is not getting enough oxygen and considered an emergency. This can lead to coma, arrhythmia, dyspnea, acute lung damage and death. Permanent deafness and blindness may occur. The symptoms are very similar in cats. The appearance of a cherry red color in the mucous membranes of dogs and cats should always indicate that there is a lack of oxygen and carbon monoxide needs to be ruled out.

Cats Sleep in Dangerous Places

Cat owners will understand when I say that cats are never happy if they begin to feel ill. And they can be quite vocal about it. In 2019, a cat named Bella saved the lives of a Florida couple who accidentally  forgot to turn off their car after pulling into the attached garage. Bella’s cries from under the bed alerted the couple, who by that point were almost too weak to dial 911 and close to collapse. The husband was close to death by the time firefighters arrived. Bella and her family survived the incident, though all suffered neurological damage. This time, the cat’s unusual behavior is what sounded the alarm.

One point to make about cats as well, is their tendency to curl up next to anything that is warm–putting them in the immediate vicinity of fuel burning devices such as heaters or fireplaces.

Treating Pets with Carbon Monoxide Poisoning

Dogs and cats who have been exposed to carbon monoxide require the same follow up as humans because neurological problems can present later on. Sometimes the prognosis for these delayed neurologic defects results in a very poor prognosis.

It is of primary importance to remove your pet and family away from the suspected source of carbon monoxide and not return until professionals have investigated. Treatment for dogs and cats is very similar to that of humans entering an emergency room. The vet will do a blood count to determine the levels in the blood and additional tests of bodily fluids to determine the impact on other organs.  An ECG may be administered to check heart function. It is highly recommended that dogs recovering from carbon monoxide exposure stay on limited activity for at least six weeks with short walks and limited playtime. Cats should also follow a limited activity regimen. Neurological symptoms can surface many weeks after the initial exposure so follow ups are a part of post exposure protocols.

Several studies have been done to follow up the long term effects of carbon monoxide exposure in pets. Seizures, sometimes fatal, can be the ultimate result of carbon monoxide poisoning. Seizures occurred after pets showed immediate initial improvement so it it vital to observe a pet who has been successfully treated and report changes to their vet.

In one such study, three chihuahuas who initially survived a house fire, recovered well initially and later succumbed to seizures, were examined. Lesions were found on necropsy compatible with carbon monoxide poisoning.

A survey by an energy company for carbon monoxide awareness month asked 2000 dog and cat owners if they owned a carbon monoxide detector. A third of those polled said that they didn’t. One in ten didn’t know carbon monoxide was dangerous. And a quarter believed that you could see, smell or taste a leak.  Yet a third of dog and cat owners believe their pets have alerted them to dangers in the home and one in ten credits their pet with saving their lives. I count myself in the last  group as a family dog alerted my family to a chimney fire when I was young. This may be true in the case of house fires or gas leaks, but our pets do not have the special ability to detect carbon monoxide–only the smoke of incomplete combustion gets to what is likely a toxic level of CO. Only carbon monoxide detectors are sensitive enough to alarm before and warn at the same time. And they help keep family pets safe as well.

In fact, a certain scenario comes to mind when discussing pets and the placement of detectors. Many working families crate or limit the access of family dogs while they are away for the day. This is often for the safety and wellbeing of the pet in addition to protecting property. Just be aware of where the pet is spending those hours. It is not uncommon for the utility room to be the area chosen and that is an area that should also be checked for carbon monoxide levels and fitted with a detector. There are not just a few people who leave the dog in the garage. Starting the car remotely or not having adequate venting for any appliances located in the garage could be deadly for your pet. Think about the areas your pets are in while you are gone and remember that they are even more susceptible to poisoning than you are.

We still have to wonder about pets carbon monoxide poisoning when we see news stories of heroics by family pets. Take, for instance, the 2008 story about the Graziani’s who were awakened at 2 am by their husky mix, Molly. Once awakened they realized something was very wrong and they were all in danger of collapse. They had removed the batteries from their carbon monoxide detector earlier because it kept alarming while they were cooking. Once awakened they replaced the batteries and it immediately sounded, so they knew it was carbon monoxide. When firefighters arrived, the carbon monoxide levels in the home were so high the firefighters had to wear self-contained breathing equipment and the carbon monoxide levels were 30 times the limit. Although neurological problems ensued, there were no fatalities.

How did Molly know something was wrong? Was Molly merely in distress because she was feeling the effects of carbon monoxide poisoning, or was it that intangible sixth sense pet owners swear by? We may ponder that question in the face of the science behind it, but there is no doubt that carbon monoxide detectors that are properly positioned and maintained save lives. Including the lives of our pets.

If carbon monoxide is suspected, vacate the home immediately. Wait for firefighters to arrive rather than returning to the home to search for pets. Carbon monoxide can act quickly to incapacitate you and ultimately become fatal. You are more likely to save your pet by being conscious when help arrives with the proper equipment.

It is also important to be aware of wildfire dangers for animals. When air quality is compromised and/or haze is present,  pets should be kept indoors with windows closed, outside activities kept to a minimum and they should be monitored carefully for signs of distress. This is especially important for animals with respiratory conditions.

The Merck Veterinary Manual also warns that facilities heated by combustion sources be tested for carbon monoxide levels with carbon monoxide monitors and/or testing the air with a Drager Tube.  This includes barns, stables, facilities for poultry or any area heated in the winter where animals are housed. Larger animals may not exhibit the severity of symptoms as a human might upon entering that environment.

For horse owners, care should be taken when sleeping inside the sleeping quarters of a horse trailer during horse shows. In 2007, two children and their grandparents were killed while sleeping in a horse trailer during the World Clydesdale show in Madison, Wisconsin. Their trailer was not manufacturer equipped with a heater so they were using a propane heater to warm the sleeping quarters. While an open roof vent was observed at the scene, this was not enough to prevent a build-up of carbon monoxide.

Remember that air even if air can escape through vents in upper levels that lack of oxygen flowing to the flame can lead to the build up of carbon monoxide in lower levels of a structure. Carbon monoxide happens when the fire doesn’t have enough oxygen, even if there is a path for the smoke or exhaust. Click here for more. 

In 2015, another couple attending the Midwest Horse fair in Madison, Wisconsin were successfully saved when a first responder attending the Fair noticed they had not shown up to feed their horse. They were found unconscious due to carbon monoxide poisoning, but alive due to the first responder’s actions.

It should be noted that heating systems included in horse trailers need to be inspected and maintained according to manufacturer specifications.

Don’t let pets carbon monoxide poisoning impact your family. While pets may not be super heroes in carbon monoxide detection, they can be indicators of the presence of carbon monoxide. They may also present unique challenges for carbon monoxide safety which we must be mindful of due to their unique responses to exposure and our exposure when indulging in pet hobbies. As always, education is a key element to insure the safety of human and pets.

Rebecca Martin authored this blog.

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