# Carbon monoxide safety when the power is out · Dark Grid Prep > Source: https://darkgridprep.cc/grid-down/carbon-monoxide-safety-during-power-outage Grid-down living ## Carbon monoxide in a blackout Keep every engine, grill and camp stove outside and at least 20 feet from the house, and put a carbon monoxide alarm with a working battery on every level. Those two rules stop the poisonings that follow almost every long outage. The house is cold, the kids are miserable, and you have a generator, a charcoal grill and a car with a full tank. Every one of them can keep your family warm or fed, and every one of them can fill the house with a gas you will never smell. This page covers where each one is allowed to run, how to keep your alarms alive with the grid down, and what to do in the first minute if one goes off. [Plan the rest of your outage, hour by hour](/grid-down/long-term-power-outage-survival) ### Why blackouts poison so many families Carbon monoxide comes from fuel that burns incompletely: gasoline, propane, natural gas, wood, charcoal, oil. The National Fire Protection Association calls it odorless and colorless, and lists heating and cooking equipment, vehicles and generators in an attached garage as the usual sources inside a home ([NFPA, carbon monoxide safety](https://www.nfpa.org/education-and-research/home-fire-safety/carbon-monoxide)). A normal day keeps most of those outside or vented. A blackout drags them indoors, because people are cold and the electric heat is gone. The February 2021 Texas freeze showed how fast that goes wrong. A Texas Tribune, ProPublica and NBC News investigation counted at least 11 confirmed deaths and more than 1,400 people treated at emergency rooms and urgent care clinics for carbon monoxide during the weeklong outage, with children making up 42 percent of the cases ([Texas Tribune, April 2021](https://www.texastribune.org/2021/04/29/texas-carbon-monoxide-poisoning)). The families in that report ran a car inside an attached garage, brought a charcoal grill into an apartment, and cooked on a portable gas stove indoors. Most had no alarm to warn them. Outside a disaster, the NFPA cites CDC figures of at least 430 deaths and roughly 100,000 emergency department visits a year from unintentional carbon monoxide poisoning that has nothing to do with fire. Storms and outages push those numbers up in a hurry, because one decision made in the cold affects everyone asleep in the house. ### Every fuel burner in a dark house Walk through your plan and put each heat or power source in one of two columns: runs outside only, or allowed inside with conditions. Most of the list belongs in the first column. * **Portable generator.** Outdoors only. Ready.gov sets the minimum at 20 feet from windows, doors and attached garages, and says the fuel stays outside too ([Ready.gov, power outages](https://www.ready.gov/power-outages)). * **Charcoal grill.** Outdoors only, including after you finish cooking. The coals keep giving off fumes after the flames die down, which is exactly how one Texas family ended up in the hospital after carrying a grill inside to heat their apartment. * **Camp stove.** Outdoors, on the same 20-foot rule as the generator, unless the manufacturer rates that specific model for indoor use and you open a window while it burns. * **Gas range or oven.** Cooking a meal on it is ordinary. Leaving it on to warm the kitchen is what Ready.gov tells you never to do, because it raises the risk of poisoning, fire and burns. * **The family car.** NFPA says no vehicle runs indoors, even with the garage door open. If you start the car to warm it up, pull it out of the garage right after it starts, and clear any snow off the tailpipe. * **Fuel-burning space heater.** Only a model rated for indoor use, with the ventilation its manual asks for, and with an alarm in the same room. * **Furnace, fireplace, wood stove and dryer vents.** These are built to vent outside, but a blizzard can block them. NFPA advises clearing snow from the dryer, furnace, stove and fireplace vents during and after a storm. If an item on your list cannot meet its condition, take it off the plan now, while you are warm and thinking clearly. ### Where the generator goes Twenty feet is the floor, and the number most people get wrong is where they measure from. Measure from the nearest opening: a bedroom window, the back door, a crawlspace vent, the attached garage. A generator on the patio under the kitchen window is inside the danger zone even though it is technically outdoors. The generator sits out in the open yard, its exhaust aimed away from the house, with an alarm near the sleeping rooms inside. Point the exhaust away from the house and away from your neighbor's house too, since their windows count as much as yours. A garage with the big door rolled up, a carport with walls on three sides and an enclosed porch all trap exhaust, and the gas then drifts through whatever door connects them to the living space. The rest of Ready.gov's generator list is about shock and fire: keep the unit dry and out of standing water, connect appliances with heavy-duty extension cords, and let the engine cool before refueling, since fuel spilled on a hot engine can ignite. Rain is the usual excuse for moving a generator into the garage. A purpose-made generator cover or a canopy staked well clear of the house solves that without bringing the exhaust closer. If 20 feet of cord feels like a burden, that is a shopping problem to solve before the storm. Buy the longer outdoor-rated cord now, while stores are open and you can pick the gauge your manual calls for. ### Alarms that keep working with the grid down Many newer homes have hard-wired carbon monoxide alarms. When the power fails, the ones without a backup battery go silent at the exact moment the household starts using generators and heaters. Ready.gov's wording is specific for this reason: detectors _with battery backup_, in central locations, on every level of the home. NFPA's placement advice goes a step further: * a central spot outside each sleeping area, plus one on every level, plus anywhere your local code requires * interconnected units where you can, so an alarm in the basement wakes the bedrooms upstairs * the mounting height the manufacturer gives, since models differ * a label from a recognized testing laboratory on the unit * a test once a month, and replacement on the schedule in the manual A chirp that is not the full alarm usually means a low battery. NFPA says to replace the battery and, if the trouble signal keeps sounding, call the fire department. Keep a spare set of the right batteries in your outage kit, separate from the flashlight batteries, so nobody borrows them. The objection here is cost. The Texas Tribune report notes that basic alarms cost as little as $15, which is less than a tank of generator fuel. A house with one on each level and one in the room where people sleep during the outage is covered for the scenarios on this page. ### Symptoms that pass for the flu NFPA lists headache, nausea, dizziness, light-headedness and shortness of breath, and warns that carbon monoxide poisoning is easily mistaken for flu or food poisoning. In the Texas report, a father whose family had collapsed in their garage first wondered whether the eggs he had cooked for breakfast had made them sick. Three patterns should make you suspect carbon monoxide during an outage rather than a bug: 1. Several people in the house feel sick at the same time, and pets seem off too. 2. People feel better after time outside or away from the house, and worse when they come back. 3. It started after a generator, heater, grill or car began running nearby. Some people are hit harder and sooner. NFPA names infants, pregnant women and anyone with a condition that limits how the body uses oxygen, such as emphysema, asthma or heart disease. Poisoning can come from a little gas over many hours or a lot of it in minutes, and someone asleep has no chance to notice either one. That is why the alarm matters more than anyone's judgment at 3 a.m. ### The first minute after an alarm sounds Treat every alarm as real until a responder tells you otherwise. NFPA's sequence is short: 1. Get everyone into fresh air at once, outdoors or at an open window or door. 2. Count heads, and include the pets. 3. Call for help from that fresh-air spot, and stay there until emergency personnel arrive. Call 911 straight away if anyone has symptoms, is confused, or will not wake up. Leave the source alone. Going back in to shut off the generator or carry out the grill puts one more person in the same air. NFPA also suggests finding out ahead of time which number your fire department wants you to call for an alarm with nobody sick. Look it up tonight and write it into your [family emergency plan](/family-plan), because during an outage the phone may be at 10 percent and the internet may be gone. ### Staying warm without making carbon monoxide Most outage poisonings start with someone trying to get warm, so the real fix is a warmth plan that needs no flame indoors. Pick one interior room, hang blankets over the doorways, and put the whole family in it with layers, hats and sleeping bags. Our [long outage guide](/grid-down/long-term-power-outage-survival) walks through setting up that room. When the cold gets beyond what blankets can handle, Ready.gov says to go to a community location with power. Local officials announce warming centers by radio, which is one more reason to keep a battery or crank radio in the kit. Older relatives and anyone with a heart or lung condition should go sooner than they want to. If you use the car as a heater or a phone charger, park it in open air, with the garage door closed behind it and the tailpipe clear of snow and ice. Run it in short sessions and crack a window. A car buried in a drift with the engine running is one of the oldest ways people die in winter storms, power or no power. For a fuel-burning heater indoors, buy one built and labeled for indoor use before the season starts, read its ventilation instructions, and set an alarm in the same room. Our guide to [safe indoor heaters for a blackout](/grid-down/safe-indoor-heaters-for-power-outages) goes through electric, propane, kerosene and wood heat one by one. If you are improvising with whatever is in the garage, the answer is to go to a warming center instead. ### What I would do tonight I'd start with the alarms, before spending a dollar on a bigger generator or a heater. Press the test button on every carbon monoxide alarm in the house, then flip the breaker that feeds them and press it again. Any unit that goes quiet with the breaker off has no working battery, and it would be useless in the one situation this page is about. That ten-minute check tells you more than any spec sheet. Next I'd walk the yard with a tape measure, find a generator spot at least 20 feet from every opening with the exhaust pointing toward open ground, and mark it with a stake. People who settle that spot in daylight are far less likely to run the generator in the garage at midnight in the rain. I'd skip buying an indoor propane heater unless the household already knows how to vent one, and plan on the warming center instead. Then write the fire department number into the family plan and move on to food, water and light. [Plan the rest of your outage, hour by hour](/grid-down/long-term-power-outage-survival) ### Frequently asked questions How far from the house should a generator be? Twenty feet is the federal minimum, measured from any window, door or attached garage. More is better, and the exhaust should point away from the house. Will a hard-wired CO alarm work during a blackout? Only if it has a backup battery in it. Press the test button after the power drops: silence means the unit is dead until the grid returns. Is it safe to sit in a running car to get warm? Only with the car parked in open air, never in a garage, and with snow cleared away from the tailpipe. A warming center is the safer choice when one is open. Can a gas stove heat a room in an emergency? Federal guidance says never. A range left burning for warmth adds carbon monoxide to the air and raises the risk of fire and burns. Written by Walt Brenner Grid-down threats, home security and family plans Walt Brenner is the pen name of the writer who covers grid-down threats, home security and family emergency plans for Dark Grid Prep. He writes from FEMA and Ready.gov guidance, utility and government reports, manufacturer manuals and long-running prepper forums, and he says plainly where those sources disagree. His beat is the household: what a family of four in a suburb or on a rural lot should have, know and do before the lights go out. [waltb@darkgridprep.cc](mailto:waltb@darkgridprep.cc) Last checked 2026-11-10 --- [ ](/) Dark Grid Prep is a survival magazine for American families who want to be ready when the grid, the economy or the supply chain fails: the threats (EMP, long blackouts, collapse, civil unrest), and how a household plans, stockpiles, communicates and secures its home through them. 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