Carbon monoxide is odorless, colorless, and lethal. The U.S. Consumer Product Safety Commission reports that an average of about 100 Americans die each year from CO poisoning linked to portable generators, and the largest share of those deaths happens during storm power outages.
At PowerOutage.us, we’ve tracked every major U.S. power outage since 2016, covering 950+ utilities and 200+ million customers. When Hurricane Helene left 4.79 million customers without power (including 1.18 million in North Carolina alone), risks from generator carbon monoxide rose as people turned to generators for power. Let’s talk about how to be safely prepared for that type of situation.
Why is carbon monoxide so dangerous during outages?
Carbon monoxide is produced any time a fuel-burning engine runs, including generators, cars, grills, and camp stoves. The gas displaces oxygen in the bloodstream by binding to hemoglobin far more tightly than oxygen does, forming carboxyhemoglobin.
This prevents your blood from delivering oxygen to your organs. The process is insidious because you can’t smell, taste, or see CO accumulating.
Symptoms progress fast:
- At moderate levels, victims experience headache, dizziness, confusion, and nausea. These symptoms mimic the flu, which is why people sometimes don’t recognize what’s happening.
- At high concentrations in an enclosed room, loss of consciousness and death can follow within minutes. People asleep or impaired by alcohol are at the highest risk because they don’t recognize early symptoms.
According to the CDC, more than 400 Americans die from unintentional CO poisoning not linked to fires each year. The majority of generator-related CO deaths occur during November through February, aligned with winter storms and the outages they cause.
For authoritative guidance on CO poisoning risks, see the CDC generator safety fact sheet and CPSC CO fatality reports.
Safe generator placement rules
The CDC recommends placing portable generators at least 20 feet away from your home, with the exhaust directed away from any doors, windows, or vents. (Note that some permanent generators can be installed closer, but the professional installer follows safety guidelines for exhaust fumes.)
Wind can carry exhaust back toward your home even from a distance if the generator is poorly positioned relative to the structure.
Never put a generator in:
- Attached garages, even with the door open
- Detached garages or sheds with occupants nearby
- Basements or crawlspaces
- Covered porches or decks adjacent to windows
- Carports with one open side
Why at least 20 feet away?
The 20-foot rule isn’t arbitrary. The structure of a home creates pressure differentials that actively pull exhaust in through gaps, vents, and door frames. A generator running in a garage with the door open still produces CO inside the home.
If rain is a concern during outdoor operation, use a generator tent or canopy rated for generator use. Don’t use tarps or makeshift covers that restrict airflow.
CO alarms are a must
Every occupied floor of your home should have a carbon monoxide alarm, and there should be an alarm outside each sleeping area. Battery-operated units or hardwired units with battery backup continue working during a power outage, which is exactly when you need them most.
CO alarms work differently from smoke detectors.
- CO alarms measure CO concentration over time, using an electrochemical sensor that integrates exposure rather than detecting a threshold peak.
- This means a low-level leak that accumulates over hours will still trigger the alarm, even if no single moment reaches an immediately dangerous concentration.
Check your CO alarm’s manufacture date. Most electrochemical sensors have a service life of 5 to 7 years. An alarm that’s past its rated lifespan may not respond accurately. The National Fire Protection Association recommends replacing CO alarms every 5 to 7 years or per the manufacturer’s instructions.
Maintain CO and medical safety
If you use powered medical devices like oxygen concentrators, CPAP machines, or refrigerated medications like insulin, create a backup plan that covers both power continuity and carbon monoxide risk. You might also consider a battery backup instead, which is safe for indoor use.
Either way, register with your local utility as a medical baseline customer to improve your chances of getting power back faster. And keep a written plan that outlines your device type, power requirements in watts, and backup method, whether that is a battery, generator, or relocation.
For detailed medical device considerations during extended outages, including oxygen concentrators and CPAP machines, see the medical device power outage checklist.
Consider generators with CO shut-off technology
Newer portable generators certified under PGMA G300-2018 or UL 2201 safety standards include automatic CO shut-off sensors. When CO builds to dangerous levels near the unit, the generator cuts off automatically. The CPSC estimates these standards reduce CO poisoning deaths by 86% to 100% compared to older generator models.
- These certifications are worth looking for specifically.
- Standard portable generators, even recent ones, don’t include this feature unless they’re specifically marketed as CO-shutoff certified.
- The technology adds some cost, but it’s the most meaningful safety upgrade available on portable generator hardware.
Inverter generators also produce CO and require the same placement rules as conventional generators. They run quieter and more efficiently, but “quieter” doesn’t mean safer. The exhaust volume is lower, but the CO concentration in that exhaust is just as lethal per volume.
For recommendations on specific generator models and features, see the generator buying guide.
How to install a generator to power home circuits safely
Installing a generator to run home circuits requires proper isolation from the grid and code-compliant wiring. Unsafe setups can backfeed electricity, putting utility workers and your home at risk.
Use a transfer switch (required)
A manual transfer switch or interlock kit isolates your home from utility power. This is the only safe way to connect a portable generator to household circuits.
- Prevents dangerous backfeeding into the grid
- Lets you select specific circuits (fridge, furnace, medical devices)
- Required by electrical codes in most areas
Install a dedicated inlet box
A licensed electrician installs an outdoor power inlet box connected to your electrical panel. This is what accepts the physical connection from the generator with a 30A or 50A connection. It also keeps cords away from your living spaces.
Connect with a proper generator cord
Use a heavy-duty, outdoor-rated generator cord that matches your generator’s output and inlet box.
- Never use standard extension cords for panel connection
- Match voltage and amperage ratings exactly
- Keep connections dry and elevated
Battery backup as a CO-safe alternative
Portable power stations and whole-home battery backup systems produce zero emissions. They’re the only backup power option that can safely operate indoors without any ventilation requirement. For people who need to power devices inside their home, especially medical equipment, CPAP machines, or lighting for small children or elderly family members, a battery system eliminates CO risk entirely.
The tradeoff is runtime. A 2,000Wh portable power station running a refrigerator and some lighting will typically last 12 to 24 hours before needing a recharge.
During Winter Storm Fern, the hardest-hit customers went over days without grid power. A battery system alone isn’t enough for that duration unless it can be recharged through solar panels (with off-grid generation capabilities) or a generator while still keeping the generator outside.
Store fuel safely during power outages
Store generator fuel in approved containers labeled for gasoline or propane and keep them in a cool, well-ventilated area away from living spaces. Fuel vapors are flammable and can accumulate in enclosed areas, increasing fire and explosion risk. Never store fuel near ignition sources like water heaters, furnaces, or electrical panels.
Rotate stored gasoline every 6 to 12 months and use a fuel stabilizer to prevent degradation. Old fuel breaks down and can clog carburetors, causing generator failure when you need it most. Keep containers sealed tightly and clearly labeled to prevent accidental misuse.
Limit storage quantities based on local fire codes and keep fuel out of reach of children. During outages, refuel generators only when they are turned off and cooled down to prevent ignition from hot engine parts.
Other CO sources to watch out for during power outages
Generators get most of the attention, but other fuel-burning devices used indoors during outages also cause CO poisoning. Other sources to be mindful of include:
- Charcoal grills and camp stoves: Many people try to cook or heat spaces with outdoor grills or stoves. Charcoal produces very high CO concentrations even in large, semi-open spaces. Never use charcoal indoors.
- Propane heaters not rated for indoor use: Some propane heaters are designed and tested for indoor use with controlled emission levels. Many are not. Check the product label before using any propane heater inside.
- Gas ranges used for heating: Leaving a gas oven or range burner on for warmth produces CO and also creates a fire risk. This is one of the more common causes of CO poisoning during winter outages.
- Running a car in an attached garage: Starting a vehicle in an attached garage, even with the door open, can push CO through shared walls into living spaces. This is a consistently documented cause of fatalities during winter storm events.
Outage events where CO risk spiked
Winter Storm Fern (January 2026) hit the Southeast with a 2,000-mile ice damage corridor. CPSC issued immediate warnings as power went out for 1,005,641 customers at peak. Nashville’s Nashville Electric Service tracked extended restoration timelines, and cold temperatures in the region pushed many households to improvise heat sources. CPSC’s winter storm guidance specifically cited CO risk from generators, heating equipment, and vehicles.
Winter Storm Uri (February 2021) created the most significant documented CO risk environment in recent memory. With 4.4 million Texas customers without power during the extreme cold, demand for portable heating and generators overwhelmed supply. CO poisoning incidents spiked across the state during the multi-day event. The cascading grid failure created a public health emergency on top of the infrastructure crisis.
Finally, Hurricane Ida (August 2021) left more than 1 million Louisiana customers without power, including all of New Orleans. Heat advisories compounded the risk as residents ran generators to power air conditioning.
Pre-storm generator safety checklist
Before a storm comes, confirm each of these before you need to use your generator:
- CO alarms tested and batteries fresh
- Generator placement site identified and at least 20 feet from home with a clear exhaust path
- Extension cords rated for the generator’s wattage and outdoor use (not indoor extension cords)
- Transfer switch or interlock kit installed if the generator will connect to home circuits (prevents back-feed onto utility lines, which can electrocute lineworkers)
- Fuel stored in approved containers, away from ignition sources
- Generator’s last service date checked (stale fuel and clogged carburetors are common failure points after months of storage)
For a full power outage preparation checklist, including food, water, and medical supplies, see the power outage emergency kit guide.
Quick recap
Carbon monoxide from generators causes a deadly, invisible risk during outages, especially in storms like Hurricane Helene. Follow CDC guidance to keep generators 20 feet away and install CO alarms. Use PowerOutage.us to monitor outages and prepare safely.