Outage Improvisations That Endanger Pets: Unvented Heaters, Candles, and Dry Ice

The power has been out since yesterday evening, the house has been getting colder by the hour, and there is a kerosene heater in the garage that came with the last place you lived. There are candles in the kitchen drawer. There is a bag of dry ice you could go get if the store still has any, because the insulin is in the refrigerator and the refrigerator is a warm box now. Three improvisations, all of them reasonable-sounding, all of them things people actually do in the first day of an outage.

They fail in three different ways, and only one of those ways is the one everybody writes about. This page is about what the fire, product-safety and industrial-gas authorities actually publish about burning fuel indoors, burning a wick indoors, and putting frozen carbon dioxide into a room where something is breathing. It is also about a piece of physics that gets fabricated constantly in pet writing, which is the idea that animals near the floor sit in the worst layer of every bad gas. That is true of one of the gases on this page. It is not true of the other, and merging the two produces advice that would put a carbon monoxide alarm in the wrong place.

If your improvisation is a generator running outside the house, that is a different problem with a different geometry and it lives on our page about what a machine running outdoors can still do to the air inside. Everything here happens indoors, in the room the animals are in.

The Rule That Outranks Everything Else on This Page

Human life comes first. Every source quoted below is written for people, and where any instruction here would have you take on personal risk to reduce an animal’s risk, follow the instruction for people.

The sharpest version of that is what to do when a carbon monoxide alarm sounds. CPSC’s consumer sheet on generators and carbon monoxide, the one marked CPSC468 0322, states: “DON’T ignore a CO alarm when it sounds. Get outside immediately, then call 911.” The same sheet states it a second way in its list of things to do: “DO know the symptoms of CO poisoning: headache, dizziness, weakness, nausea, vomiting, sleepiness, and confusion. If CO poisoning is suspected, get outside immediately, then call 911.”

NFPA’s carbon monoxide guidance gives the same instruction with three extra steps attached: “If the CO alarm sounds, immediately move to a fresh air location outdoors or by an open window or door. Make sure everyone inside the home is accounted for. Call for help from a fresh air location and stay there until emergency personnel.” UL Solutions, writing for code officials, states the same stay-out rule more explicitly: “Do not reenter the premises until the emergency services responders have given their permission.”

There is no version of any of those sentences with a pet clause in it, and this page is not going to write one. Get outside is get outside. If the animals come with you as you go, good. If an animal is in a back bedroom and you are already feeling the symptoms in that list, going deeper into the building is how a one-casualty incident becomes a two-casualty incident, and the responding crew who arrives with breathing apparatus is the resource that can go where you cannot.

What that costs a pet owner is real and worth naming plainly instead of glossing: you may end up standing on the sidewalk waiting while your animal is still inside. The way you make that hour survivable is not by negotiating with the instruction. It is by doing the preparation that keeps the alarm from sounding in the first place, which is the rest of this page, and by having the animals’ locations, crates and a leash by the door already sorted, which is what our drill for getting animals out of a building fast is for.

The Physics Error This Page Exists to Correct

Pet writing loves a single unifying mechanism: animals are low, bad gases are low, therefore animals breathe the worst air. It is a tidy story and it is half wrong.

Carbon monoxide does not reliably pool at pet height. The ASPCA, writing specifically about pets and carbon monoxide, states: “Carbon monoxide is roughly the same density as room air, so animals close to the ground are at no more risk than taller animals.” The very next sentence is the exception that survives, and it survives on different grounds: “However, birds, due to their unique respiratory system are more sensitive to the effects of carbon monoxide than other animals are.” So the bird risk is respiratory, not gravitational.

Carbon dioxide, the gas dry ice turns into, genuinely is heavier and genuinely does accumulate low. The Compressed Gas Association states that carbon dioxide gas is colorless, odorless and “about 1.5 times as heavy as air”. CGA’s dry ice storage instructions are built around that fact, telling users to “Store in cool, well ventilated areas” and that “Ventilation systems should exhaust from lowest level and make up from higher point.” Exhaust from the lowest level is a published instruction that only makes sense for a gas that collects at the bottom of a space.

Why does the difference matter enough to open the article with it? Because it changes where you put a detector. If you believed the merged version, the reasonable-sounding next move would be to mount a carbon monoxide alarm low, near where the dog sleeps. That is a detection failure dressed up as pet care. NFPA’s guidance is to “Follow the manufacturer’s instructions for placement and mounting height”, and that instruction is not overridden by anything you believe about your animal’s height.

Keep the two gases separate for the rest of this page. The unvented heater section is a carbon monoxide section. The dry ice section is a carbon dioxide section. They do not share a mechanism, and the only thing they truly share is that neither one announces itself.

Improvisation One: Burning Fuel Indoors for Heat

This is the improvisation that kills people, and it comes in more shapes than owners expect: a kerosene heater, an unvented propane radiant heater, a camping stove or lantern brought inside, a charcoal grill on the kitchen floor, and the oldest one of all, the gas oven with the door open.

What the agencies publish about each shape

The instructions are not ambiguous, and they come from five different bodies that agree with each other.

The gas oven or stovetop. Ready.gov’s power outage page states: “Do not use a gas stove or oven to heat your home. It increases your risk of carbon monoxide poisoning. Using an oven or stovetop can also increase the risk of fires, burns and could damage the appliance.” CDC’s carbon monoxide basics page states “Never heat your house with a gas oven” and, in the sentence immediately after, “Don’t cook or burn anything on a stove or fireplace that isn’t vented.” USFA’s heating page states “Never use an oven to heat your home.” The American Red Cross states “Don’t use a gas stove to heat your home and do not use outdoor stoves indoors for heating or cooking.”

Charcoal. CDC states: “Never burn charcoal indoors. Burning charcoal - red, gray, black, or white - gives off CO.” The color list in that sentence exists because people assume a grill that has stopped flaming has stopped emitting. It has not.

Camp stoves and portable fuel-burning lanterns and heaters. CDC states “Never use a portable gas camp stove indoors. Do not use portable flameless chemical heaters indoors.” Flameless is not the same as combustion-free: a catalytic or chemical heater with no visible flame still produces carbon monoxide, and CDC prohibits it indoors by name in that same sentence. If your outage plan includes one because it was sold as a no-flame option, the absence of a flame is not the test that matters here. CPSC’s carbon monoxide page on portable heaters and camping equipment states: “Never use fuel-burning portable heaters or lanterns while sleeping in enclosed areas such as tents, campers and vehicles.” The longer version on the same page adds a detail worth carrying if your outage plan involves sleeping in a vehicle with an animal: “Do not use portable heaters or lanterns while sleeping in enclosed areas such as tents, campers, and other vehicles. This is especially important at high altitudes, where the risk of carbon monoxide poisoning is increased.”

Portable generators, for completeness and then no further. CPSC468 0322 states: “DON’T operate a portable generator inside a home, garage, basement, crawlspace, shed or on a porch; and never leave a car running in an attached garage.” The rest of that machine’s rules, including the placement distance and the exhaust direction that travels with it, belong to our page on the machine that runs outside the house and are quoted there with their own reference points. Do not carry a number from that page onto this one.

The position the engineers take on unvented heaters as a class

The most current and most direct statement we located is not from a fire agency. It is from ASHRAE, the professional body for heating, ventilating and air conditioning engineers, in its Position Document on Unvented Combustion Devices and Indoor Air Quality, approved by the ASHRAE Board of Directors on June 4, 2026. Its positions include, verbatim:

• “Vented combustion devices result in less exposure to combustion-related pollutants than unvented combustion devices.”
• “Unvented combustion devices should never be used as the primary/sole source of heating.”
• “Consumers who want to reduce the risk of adverse health effects due to exposure to combustion products should not use unvented devices.”
• “Carbon monoxide alarms should be installed in all homes with unvented combustion devices.”
• “Unvented room heaters should not be fueled with fuels that are liquid at atmospheric pressure, e.g., kerosene, alcohol, gasoline, or diesel fuel.”
• “When an unvented combustion device is used, it should be operated according to the manufacturers’ instructions and local codes, and installation should be performed by a qualified installer.”

Under its recommendations, the same document states that “Any existing unvented combustion heating devices that do not meet the positions above be removed from operation.”

Two scope notes, because a quotation that travels without them becomes a different claim. First, this document explicitly excludes candles: it states that “Unvented combustion emissions from candles, incense, and devices that burn solid fuels are excluded from this position document.” Nothing in the ASHRAE list is a statement about a candle, a wood stove or a fireplace. Second, ASHRAE’s positions are written for people and indoor air quality generally. Nothing in the document addresses animals.

What CPSC publishes for people who already own a kerosene heater

CPSC has not written the unvented heater out of existence. Its publication CPSC Stresses Kerosene Heater Safety, Pub. 5052 009403, Revised 4/2011, is written for someone who is going to use one, and it is worth reading in its own words rather than in either direction’s summary of it.

On the pollution question it states: “Reduce your exposure to indoor air pollutants by properly operating and maintaining your kerosene heater. Although kerosene heaters are very efficient while burning fuel to produce heat, low levels of certain pollutants, such as carbon monoxide and nitrogen dioxide, are produced. Exposure to low levels of these pollutants may be harmful, especially to individuals with chronic respiratory or circulatory health problems.”

The rules it then gives are, verbatim: “Operate your heater in a room with a door open to the rest of the house.” And: “Open an outside window approximately one inch to permit fresh air to effectively dilute the pollutants” if you must operate with the door closed, or if the home is relatively new and tight, or older but winterized to reduce air infiltration. It also states “Always use your heater according to the manufacturer’s instructions” and “Never refuel the heater inside the home.”

Read what that document is and is not doing. The heading over those rules is reduce your exposure. The framing sentence says exposure to low levels of these pollutants may be harmful. At no point does it say the result is safe, and at no point does it mention an animal. A cracked window is a dilution measure that CPSC publishes for humans, and this page will not upgrade it into a permission slip for a room with a parrot, a rabbit or a sleeping dog in it.

The other thing to notice: CPSC’s document is dated 2011 and ASHRAE’s is dated 2026, and they are not actually in conflict. One is instructions for a person who owns the appliance. The other is a recommendation about whether to own it.

The words on the box, and the sensor whose name tells you what it senses

Walk into a hardware store during an outage and the propane heater on the endcap will be marketed as indoor safe. That is not a slur on the manufacturer, it is literally how the category is sold. Mr. Heater’s own product page for its Portable Buddy heater describes it as an “Indoor safe radiant propane heater” and states that “With the Oxygen Depletion Sensor (ODS) and accidental tip-over safety shut-off you can be sure that you will enjoy years of comfortable indoor safe heat.”

Two honest observations about that sentence, neither of which requires calling it wrong.

First, it is a claim about a product category and a set of features. It is not a statement about animals, and no manufacturer marketing we read for any unvented heater addressed animals at all.

Second, look at what the sensor is named after. The fuel gas provisions that govern unvented room heaters describe the required shutoff in oxygen terms. Section G2445, as adopted in the Texas Windstorm Insurance Association Residential Code 2024 and published by UpCodes, states: “Unvented room heaters shall be equipped with an oxygen-depletion-sensitive safety shutoff system. The system shall shut off the gas supply to the main and pilot burners when the oxygen in the surrounding atmosphere is depleted to the percent concentration specified by the manufacturer, but not lower than 18 percent.” The trigger described in that code text is an oxygen concentration. ASHRAE, for its part, takes the position that unvented gas-fired room heaters “should be equipped with oxygen depletion sensors (ODSs)” and, in the same list, that consumers wanting to reduce their exposure risk should not use unvented devices at all. A recommended feature and a recommended avoidance can sit in the same document without contradiction, and both of them survive.

Third, the same code family goes further than a recommendation. Two sections before the oxygen-depletion requirement, the same code text states: “One or more unvented room heaters shall not be used as the sole source of comfort heating in a dwelling unit.” So in at least this jurisdiction, “never the primary or sole source of heating” is not only ASHRAE’s professional position, it is prohibited use under adopted code. Whether your own jurisdiction has adopted the same provision is a question for your local building or fire department, not for this page, but it is worth asking rather than assuming ASHRAE’s position is merely a recommendation everywhere.

None of that tells you the appliance is fine in a closed room with a cat in it. What it tells you is where the answer lives, which is the next section.

Clearances, room size and permitted locations are not ours to publish

You will notice this page has given you no distance for a heater. That is deliberate.

Clearance to combustibles, minimum room volume, permitted rooms and the input rating an appliance may have are set by that appliance’s own manual and by the fire and fuel gas codes your jurisdiction has adopted. Those vary. ASHRAE’s own position is that an unvented combustion device “should be operated according to the manufacturers’ instructions and local codes, and installation should be performed by a qualified installer.” The generic figures the fire agencies publish are for a different question, the fire question, and they are worth having: USFA’s heating page states “Keep anything that can burn at least 3 feet from all heat sources including fireplaces, wood stoves, radiators, space heaters or candles”, and NFPA’s Heating Safety tip sheet, marked ©NFPA 2017, states “Keep anything that can burn at least three-feet (one metre) away from heating equipment, like the furnace, fireplace, wood stove, or portable space heater.” Those are clearances for things that burn. They are not carbon monoxide clearances, and they are not written with an animal’s bed, a bird cage stand or a plastic crate in mind.

So the two calls to make, and neither of them is to us: the appliance manufacturer for anything about that model, and your local building or fire department for what your jurisdiction permits.

One number USFA publishes that changes how you rank the risk

Portable heaters are a small share of heating fires and a large share of the fatal ones. USFA’s heating page states: “Home portable heater fires were only 3% of all home heating fires annually for 2017-2019, but they accounted for 41% of fatal heating fires in homes.”

That is a fire statistic about people, not about pets, and it is worth reading for what it does say. The appliance you drag out of the garage for one cold night is over-represented in the outcomes that end worst. If your winter outage plan currently reads “there is a heater in the garage,” our cold-weather preparation page for pet households covers the non-combustion side of staying warm, and portable power stations that run electric loads without a flame covers the equipment answer.

The Alarm Section, Which Applies to Every Improvisation Above

If anything in your house is burning fuel, this part is not optional and it is not pet-specific.

The instruction, verbatim from CPSC468 0322: “DO install battery-operated CO alarms or CO alarms with battery backup outside sleeping areas, and on each floor of your home. Test alarms monthly.” Note the battery clause. During an outage a hardwired-only alarm is a decoration.

The siting guidance, verbatim from NFPA’s carbon monoxide page: CO alarms “should be installed in a central location outside each sleeping area and on every level of the home and in other locations where required by applicable laws, codes or standards.” NFPA adds: “For the best protection, interconnect all CO alarms throughout the home. When one sounds, they all sound.” And then the sentence that settles the pet question: “Follow the manufacturer’s instructions for placement and mounting height.” NFPA also states to “Choose a CO alarm that has the label of a recognized testing laboratory” and “Test CO alarms at least once a month; replace them according to the manufacturer’s instructions.” One more line from the same list is worth doing this week rather than during an outage: “Call your local fire department’s non-emergency number to find out what number to call if the CO alarm sounds.”

The code, cited correctly. Household carbon monoxide alarm requirements are in NFPA 72, National Fire Alarm and Signaling Code, whose current edition is 2025 per NFPA’s own product page. UL Solutions states the lineage plainly: “NFPA 72, the National Fire Alarm and Signaling Code, incorporates the requirements for CO alarms previously covered in NFPA 720. NFPA 72, Sections 17.12 and 29.7 include similar requirements for the installation of CO alarms, along with additional requirements for a distinctive alert tone, power supplies, installation, maintenance and testing.” If you see NFPA 720 cited as the live household CO standard, that citation is stale.

What the alarm is calibrated to, and why that is a pet fact. CO alarms are investigated to UL 2034, the Standard for Single and Multiple Station Carbon Monoxide Alarms. UL Solutions states that “The UL 2034 Sensitivity Test is based on a 10% COHb level, which may be imperceptible or produce only a slight headache.” The sentence that follows it in the same paragraph is the operational one: “Keep this in mind when a CO alarm activation is reported.”

Sit with that for a second, because it is the honest version of a claim this niche usually gets wrong. The alarm on your ceiling is engineered around a human blood measurement. It is not a pet monitor, it was never designed as one, and no source we read describes any consumer alarm as calibrated for animals. That is not an argument for skipping the alarm. It is an argument for treating an alarm activation as a whole-household event and for not reasoning backwards from “the pet seems fine” to “the air is fine.”

Three things not to do with an alarm because of a pet. Do not mount it low so it is near the animal, since the manufacturer’s instructions govern height and the ASPCA’s density statement removes the premise anyway. Do not skip a level of the house on the grounds that only the pets are on it, since CPSC’s instruction is every floor. And do not treat a bird as an early-warning device. That practice belongs to the history of coal mining, and a bird’s greater sensitivity is a reason to protect it, not a reason to assign it a job.

Improvisation Two: Candles

The candle is not a heat improvisation, it is a light improvisation, and the agencies have a shorter answer for it than they do for heaters.

The agencies do not ask you to be careful with candles in an outage

They ask you not to use them.

NFPA’s Candle Safety tip sheet, marked NFPA 2025, lists among its instructions: “Have flashlights and battery-powered lighting ready to use during a power outage. Never use candles.”

USFA’s candle page states: “Use flashlights, not candles, if you have a power outage.” Its severe weather page is blunter: “Never use candles for emergency lighting. Use flashlights and stock up on extra batteries.”

The American Red Cross power outage guidance states: “Use flashlights, not candles.”

Three separate bodies, same instruction, no conditions attached. That is about as close to unanimous as this material gets.

The size of the problem, from NFPA’s own current statistics

NFPA’s candle page publishes the following for the five-year period 2020 to 2024, in its own words:

• “U.S. fire departments responded to an annual estimated average 5,894 home structure fires whose heat source was candles.”
• “These fires cause an annual average of 63 civilian deaths and 532 civilian injuries.”
• “Candles were the heat source for 2% of reported home fires, 2% of home fire deaths, 5% of home fire injuries.”
• “Over Half of all candle fires started when a flammable piece of décor – such as furniture, mattresses, bedding, curtains, home decorations, paper, or clothing – was too close to the lit candle.”
• “In 21% of home structure candle fires, the candle was either left unattended, discarded, or otherwise misused.”
• “Over one-third of candle fires (36%) started in the bedroom. Sleep was a factor in 11% of home structure candle fires, 34% of candle fire deaths, and 17% of candle fire injuries.”

Three numbers matter most for a household with animals: the too close number and the unattended number, because those are the two failure modes a pet actively creates, and the sleep number, because sleep was a factor in 11 percent of candle fires but 34 percent of candle fire deaths, and separately over a third of candle fires (36%) started in the bedroom. An animal moves the things that can burn, and an animal is in the room during the hours you are not, which is also frequently the room you are asleep in. That asymmetry between the fire share and the death share, not a single blended figure, is the statistic behind the instruction later on this page to blow out every candle before bed.

The geometry problem, which is the part pet owners have to solve

Here is where a general candle-safety page stops being enough.

USFA’s instruction is: “If you do use lit candles, make sure they are in stable holders and place them where they cannot be knocked down easily.” NFPA’s tip sheet says the same thing from the holder’s side: “Use candle holders that are sturdy, and won’t tip over easily.” NFPA’s tip sheet also publishes a clearance: “Keep candles at least 1 foot (30 centimeters) away from anything that can burn.”

Now read “where they cannot be knocked down easily” as a cat owner. The places a person instinctively picks as out of reach are counters, mantels, bookshelf tops and the back of a toilet tank. Those are exactly the surfaces a cat treats as a route. A dog’s version is different and just as real: a wagging tail at coffee-table height, a startled scramble when the transformer bangs outside, a nose that investigates anything new at floor level. A candle placed for a household with a toddler in it has been placed against a small child’s reach. A cat does not have that ceiling.

There is no published figure for how far a cat can jump that belongs in a safety instruction, so this page will not manufacture one. The usable version of the rule is a question rather than a number: is there any surface in this room the animal cannot get onto, and is that where the flame is? For most households with a cat, the honest answer is no, and that answer is the argument for the swap rather than for a better shelf.

The clearance numbers do not agree, so use the larger one

This is a small thing that a careful reader will catch, so here it is out loud.

NFPA’s Candle Safety tip sheet publishes “at least 1 foot (30 centimeters) away from anything that can burn.” USFA’s candle page publishes “Keep candles at least 12 inches away from anything that burns.” Those two agree. But USFA’s heating page groups candles into a different rule entirely: “Keep anything that can burn at least 3 feet from all heat sources including fireplaces, wood stoves, radiators, space heaters or candles.”

So the same federal agency publishes twelve inches on the page about candles and three feet on the page that lists candles among heat sources. We are not going to reconcile that on their behalf or split the difference into a number nobody published. The larger figure satisfies both, and if the candle is anywhere near a pet bed, a blanket, a cardboard scratcher or a pile of paper, the larger figure is the one to work to.

Two more published candle lines that matter in an outage house

NFPA’s tip sheet includes: “Never use a candle if oxygen is used in the home.” If anyone in the household is on home oxygen, that sentence is a hard stop and it outranks every convenience argument on this page.

And: “Blow out all candles when you leave the room or go to bed. Avoid the use of candles in the bedroom and other areas where people may fall asleep.” During a long outage, the room where people fall asleep and the room where the animals sleep are usually the same room, and it is usually the one room the household has decided to keep warm.

Birds and the second candle hazard, which is not fire

A candle in a room with a bird is two hazards, and the second one does not need to tip over.

The Merck Veterinary Manual chapter on toxicoses of pet birds, authored by Sharman M. Hoppes, DVM, DABVP (Avian), fully reviewed September 2021 and last updated May 2026, closes its section on inhaled hazards this way: “Other aerosols, including some carpet fresheners, plastics either melted or burned in a microwave oven, perfumes, deodorizers, votive candles, and new heating duct systems may also be irritating or toxic to caged birds.”

The Association of Avian Veterinarians, in its client handout Protecting Your Pet Birds from Household Dangers, copyright 2022, opens the same topic with the mechanism: “The avian respiratory tract is extremely sensitive to inhaled chemicals. Products that do not cause problems in people or other mammals can be highly toxic to birds. Below is a list of some common products that are not safe to use around birds. If your bird breathes in these chemicals it can result in symptoms ranging from mild illness to sudden death.” That range runs to death, not only irritation, which is the weight to put on the word “toxic” the rest of this section uses. Its list of other airborne toxins includes “air fresheners, hair products, nail polish, scented candles, aerosols, gasoline fumes, paints, polyurethane, mothballs, fumigants, drain cleaners, aerosol insecticides, and cleaning products such as ammonia and bleach.” The same handout’s instruction, in AAV’s own words, is written for a specific trigger: “If painting or other home repairs are being done in your home, your birds need to be moved far away from any fumes, preferably to another location altogether.” AAV does not extend that sentence to candles by name. This page’s own reasoning, not AAV’s, is that the same logic applies to any indoor fume source with a bird in the house, candle smoke and scent included: move the bird far away, and preferably to another location altogether, rather than trusting the far side of the room.

AAV’s smoke paragraph adds a detail that changes how you interpret a bird that looks fine: “All smoke, whether from cigarettes, marijuana, engine exhaust, burning food, self-cleaning ovens, or malfunctioning furnaces, can hurt your pet. Carbon monoxide, hydrogen cyanide, acidic fumes, and particulate matter in smoke cause symptoms similar to PTFE.” The sentence immediately after that one is the one people skip: “Symptoms may take several hours to appear.”

No source we read names any wax, fragrance or product as safe around birds. There is no bird-safe candle on this page because we could not source one, and the search for one is not a search you want to be running by flashlight in the dark. The full picture of what a bird’s airway does and does not tolerate is on our page about the airway that fails first in a fume event.

Improvisation Three: Dry Ice

Dry ice enters an outage for a specific reason: a refrigerator full of insulin, a freezer full of food, a reptile that needs the opposite of what dry ice does. It is a real tool, sold to consumers, and this page is not going to tell you never to buy it. It is going to tell you what it turns into and where that goes.

What CGA publishes

The Compressed Gas Association describes dry ice as the solid form of carbon dioxide, extremely cold, that “rapidly sublimates, or converts, into carbon dioxide gas at room temperature.” It names the hazards as “the extremely cold temperature, potential to create an oxygen-deficient atmosphere, and rapid conversion from a solid to gas”, and states that “It is critical that users read and follow the instructions and safety precautions provided by their dry ice supplier.”

Its storage instructions, verbatim: “Store in cool, well ventilated areas.” “Ventilation systems should exhaust from lowest level and make up from higher point.” “Install carbon dioxide monitors.” “Check carbon dioxide concentration before entering storage area.” “NEVER store in airtight containers.”

Its transport instructions, verbatim: “NEVER transport in airtight containers.” “Open windows or ensure constant supply of fresh air in vehicles.” And in the longer product information section: “If transporting in the passenger compartment or trunk of a vehicle, limit dry ice to small quantities and open all windows or ensure constant supply of fresh air for the duration of the trip.”

On leaks and accumulation: “Because dry ice rapidly sublimates, or converts, into carbon dioxide gas ventilate adjacent enclosed areas to prevent the formation of dangerous concentrations of carbon dioxide. A concentration of 3% of carbon dioxide can be dangerous while higher concentrations can be lethal.” The sentence directly after that one is the part that tells you how seriously CGA means it: “Persons including rescue workers should not enter areas in which the carbon dioxide content exceeds 3% unless wearing an SCBA or supplied-air respirators.”

On disposal: “The best method for disposal is to allow the dry ice to sublime or evaporate to the atmosphere in a well-ventilated area where no buildup of carbon dioxide vapor can occur.”

Reading those instructions as a pet owner

Three of those sentences change shape when there is an animal in the house.

The car. CGA’s vehicle instruction is written for a person driving with dry ice. If the animal is in that car, the instruction gets stricter rather than looser, because a crated animal cannot move to the window that is open. Open windows, keep the quantity small in the way CGA describes, and do not put a cooler of dry ice in a sealed trunk or cargo area that shares air with a carrier.

The floor. This is the one place on this page where the low-animal intuition is correct. Carbon dioxide is about 1.5 times as heavy as air, and CGA’s own ventilation design instruction is to exhaust from the lowest level. A crate on the floor, a rabbit in a hutch at ankle height, a tortoise table, a cat under a bed: those are all in the layer CGA designs exhaust for. CGA does not publish a room-by-room judgment call for that layer. It publishes a condition and an instrument: dry ice belongs in a non-airtight container in a cool, well-ventilated area, and the way CGA says to know whether a space qualifies is a carbon dioxide monitor, installed and checked before entering, not a visual read of whether the room feels open. It is a reason never to put dry ice in a closed room, a closet, a bathroom, a garage or a vehicle where an animal is confined, and never to use it in a small enclosed space at all.

The container. The airtight rule exists because the gas needs somewhere to go. The improvised version of that mistake in a pet household is putting dry ice inside a sealed cooler and then putting the cooler inside a closed vehicle or a closed room, which converts one enclosure into two.

Contact and ingestion, which is a different hazard from the gas and gets no separate warning on this page until now. CGA’s own safety reminders, in the section headed “Handling Dry Ice”, list two instructions: “Use protective gloves or tongs” and “NEVER handle with bare hands or place in mouth”. Its product information section states the mechanism in full: “Dry ice is extremely cold and can freeze human tissue on contact. Never place dry ice in your mouth. If swallowed, the dry ice will rapidly expand and can cause serious injury or death.” Those sentences are written for a person who can read the label, put on gloves and choose not to put a block of dry ice in their own mouth. CGA never addresses an animal anywhere in this material, so what follows is this page’s own reasoning, not CGA’s: an animal cannot read that warning and cannot choose not to mouth a dropped chunk. A dog that mouths one, or a cat that lies against an unlidded cooler, is walking into the same tissue-freezing contact and the same swallowing hazard CGA describes for a person, with none of the judgment CGA is assuming when it writes the warning. Dry ice must be behind a closed, non-airtight lid an animal cannot open, and out of an animal’s reach at all times, not only while it is subliming in the open. If a pet has touched dry ice or is suspected to have swallowed any, that is an emergency veterinary call, not a wait-and-watch.

The occupational limit is not a pet number

You will see 5,000 parts per million quoted around carbon dioxide, and it deserves to be labeled precisely.

That figure comes from OSHA’s Table Z-1 in 29 CFR 1910.1000, which lists carbon dioxide at 5000 ppm. The rule attached to it, in the regulation’s own words at paragraph (a)(2), is: “An employee’s exposure to any substance in Table Z-1, the exposure limit of which is not preceded by a “C”, shall not exceed the 8-hour Time Weighted Average given for that substance in any 8-hour work shift of a 40-hour work week.” The same table lists carbon monoxide at 50 ppm.

Read the subject of that sentence. An employee. It is an eight-hour time-weighted average built around a forty-hour work week for adult human workers, and it is a limit on employer-controlled exposure rather than a line below which any individual is fine. It is not a pediatric limit, it is not a limit for a person with heart or lung disease, and it is emphatically not a threshold for a dog, a cat, a bird, a rabbit or a reptile. A parrot’s respiratory anatomy is not a mammal’s, and a small mammal in a hutch at floor level is not a standing adult in a ventilated workplace. Do not use that number to decide whether a room is acceptable for an animal.

What is not published, said out loud

We looked for a carbon dioxide exposure threshold specific to companion animals, in veterinary and agency sources, and did not locate one. The searches behind that sentence covered the veterinary references, the ASPCA’s toxicology material, CGA’s own dry ice and carbon dioxide guidance, and OSHA’s air contaminant tables, and what they returned were human occupational values and human physiological effects. That is a statement about what we could find and what those bodies publish for people, not a claim that no such figure exists anywhere in the literature.

It also means an empty cell is the correct output here. This page publishes no pounds-per-cooler figure, no sublimation rate, no room ventilation rate and no minimum room size for dry ice, because the sources that publish those numbers publish them for storage facilities and shippers, and because a wrong number here would be worse than no number. Two humans can close that gap for you: the dry ice supplier, who CGA says is the source of the handling instructions you should be following, and your veterinarian, for anything about the animal.

If your reason for wanting dry ice is refrigerated medication, that decision has its own page: what the package inserts actually say about a warm refrigerator works the drug-stability question rather than the cooling-method question.

The Three Improvisations Side by Side

Every cell below is what the named source publishes, in summary form, with the verbatim wording quoted in the sections above. Where a source does not publish something, the cell says so rather than borrowing from a neighbor.

Improvisation	The hazard it creates	What the named sources publish	The substitute those same sources name
Unvented heater, gas oven, camp stove, charcoal indoors	Carbon monoxide, plus nitrogen dioxide from kerosene per CPSC	ASHRAE: never the sole heat source, and consumers reducing exposure risk should not use unvented devices. CDC: never a gas oven for heat, never charcoal indoors, never a portable gas camp stove or portable flameless chemical heater indoors. CPSC: never fuel-burning heaters or lanterns while sleeping in enclosed areas	No source we read names a combustion substitute. Electric loads on stored power, added insulation and layered bedding are the non-combustion route, and going somewhere with heat is the one Red Cross names
Candles for light	Fire ignition, plus airway irritation for birds	NFPA and USFA: never use candles for outage lighting. NFPA 2020 to 2024 data: an annual average of 5,894 home structure fires with candles as the heat source, over half from something flammable too close, and sleep a factor in 34% of candle fire deaths. Merck and AAV: votive and scented candles are on the list of airborne hazards for caged birds	Flashlights and battery-powered lighting, named explicitly by NFPA, USFA and the American Red Cross. NFPA also names flameless candles
Dry ice for cooling	Carbon dioxide accumulation, which CGA states is about 1.5 times as heavy as air, plus contact injury from freezing tissue and injury from ingestion	CGA: store in cool well ventilated areas, never in airtight containers, never transport in airtight containers, open vehicle windows, ventilate adjacent enclosed areas, use protective gloves or tongs, never handle with bare hands or place in mouth, and follow the supplier’s instructions	CGA names no substitute. It names conditions of use and a person to ask, which is the supplier

Notice what the third row does not contain. There is no swap for dry ice the way flashlights are a swap for candles, because dry ice is doing a job nothing else in the house can do. That is precisely why its rules are conditions rather than a replacement.

What This Page Does Not Know, and Who to Ask

Stating the gaps is not a disclaimer, it is the part that keeps you from filling them with something invented.

No animal threshold for either gas appears here. We publish no parts-per-million figure at which a dog, cat, bird, rabbit, reptile or small mammal is harmed by carbon monoxide or carbon dioxide. Numbers for animals do circulate in veterinary references, and a household has no way to act on one without a calibrated instrument. Ask your veterinarian about your specific animal, especially for birds and for any animal with existing respiratory or cardiac disease. If you suspect an exposure, the ASPCA’s instruction is unambiguous: take the animal to a local emergency veterinarian immediately.

No clearance, room size or permitted location for any appliance appears here in our own voice. Those belong to the appliance and the jurisdiction. Ask the manufacturer for that model, and ask your local building or fire department for what your jurisdiction has adopted.

No wattage or runtime appears here. If your plan is to replace a flame with an electric load on stored power, the arithmetic belongs to the device’s own label and the power station manufacturer’s own published capacity, not to us.

No dry ice quantity appears here. Ask the dry ice supplier, whose instructions CGA names as the ones to follow.

Retrieval note, so you can judge the sourcing. CPSC’s carbon monoxide information center page on portable heaters and camping equipment and CDC’s carbon monoxide basics page both returned HTTP 403 to a direct request on August 11, 2026, and both were read instead through the Internet Archive, at captures dated April 19, 2026 and August 7, 2026 respectively, with the archive URLs and dates listed in the sources. A failed request is a retrieval problem, never evidence that an agency is silent, and both agencies publish the documents quoted here.

Your Outage Improvisation Checklist

• Put battery-operated CO alarms, or CO alarms with battery backup, outside sleeping areas and on each floor, and test them monthly. That is CPSC’s instruction, and the battery clause is the part that matters in an outage.
• Read the alarm’s own installation instructions for mounting height and follow them. Do not mount an alarm low because an animal is low.
• Buy the flashlights and battery lanterns before the season, because the swap the agencies name only works if the batteries are already in the drawer.
• Decide now whether any unvented combustion appliance is going to be part of your plan at all, and read ASHRAE’s positions before you decide rather than in the middle of a cold night.
• If you own one, find its manual today and read the clearance, room and ventilation requirements while the lights are on. Call the manufacturer if the manual is gone.
• Call your local fire department’s non-emergency line once and ask what your jurisdiction permits for unvented room heaters, and what number to call if a CO alarm sounds. NFPA names that second question specifically.
• Walk the room your household will actually occupy during an outage and identify every surface a cat can reach. If a flame would have to sit on one of them, the flame does not go in that room.
• If there is a bird in the house, plan its location away from any room where anything will be burned, scented or vaporized, and remember AAV’s instruction is another location, not the far corner.
• If anyone in the household uses home oxygen, no candle enters the building. NFPA states it as an absolute.
• If dry ice is in your plan, ask the supplier for handling instructions, and rule out in advance any closed room, closet, bathroom, garage or vehicle where an animal would be confined with it.
• Keep dry ice behind a closed, non-airtight lid an animal cannot open and out of reach at all times. CGA’s own warning against bare-hand and mouth contact is written for a person who can read it; an animal cannot, and contact or suspected ingestion is an emergency veterinary call.
• Write down where each animal sleeps and where the crates and leashes are, so that leaving fast does not require a search.
• Agree the human rule with everyone in the house before you need it: if a CO alarm sounds, everyone goes outside and then calls 911, and nobody goes back in.

Where to Go Next

This page is the improvisation spoke of our outage playbook for pet households. The rest of the outage problem splits three ways.

If the improvisation is outdoors. The twenty-foot rule and the exhaust direction that travels with it covers the machine that runs outside the house, including the alarm rules for the household it powers and the veterinary signs of exposure. Do not mix its placement figures with anything on this page.

If the animals are the constraint. The airway that fails first in a fume event covers the bird-specific side in full. Tanks and terrariums, which need heat you cannot improvise with a flame covers the animals whose environment is the equipment. Getting animals out of a building quickly covers the exit the alarm section above assumes you can make.

If the season is the constraint. Cold-weather preparation for a pet household covers the non-combustion route to a warm room, and stored power sized to real loads covers the equipment that replaces a flame with a plug.

Then do the one thing on the checklist that has to happen on a quiet afternoon rather than during an outage: put fresh batteries in the CO alarms, put a flashlight in the room each animal sleeps in, and find the manual for whatever is in your garage. The improvisation you will reach for deep into a cold night is the one that is already within arm’s reach, so change what is within arm’s reach.