Where
On every level of the home and outside sleeping areas, per CPSC. The CDC asks for one near every sleeping area.
CPSC: CO center
Power, heat and light
Portable generator safety and carbon monoxide
Run a portable generator outdoors only, at least 20 feet from the house with the exhaust pointed away, and never inside a home, garage, basement or shed, even with the doors open. Put battery-powered CO alarms on every level, and if one sounds or anyone feels dizzy or sick, get outside and call 911.
Why generators and carbon monoxide go together
Every portable generator makes carbon monoxide (CO), a colorless, odorless gas. You can't see it or smell it, which is why the placement rules and alarms below matter so much.
CPSC reports that an average of about 100 people in the U.S. die each year from CO poisoning linked to portable generators. Across all non-fire sources, the CDC counts more than 400 deaths, more than 100,000 emergency department visits and more than 14,000 hospital stays a year.
Where the generator goes
Four agencies use the same 20-foot figure, measured from slightly different points.
| Agency | How far | From what |
|---|---|---|
| CPSC | At least 20 feet | The house and other buildings, with exhaust directed away from windows, doors and vents |
| CDC | More than 20 feet | Windows, doors and vents |
| Ready.gov | At least 20 feet | Windows, doors and attached garages (generator and fuel) |
| NFPA | At least 20 feet (7 metres) | All doors, windows and vent openings, measured from the generator to the building |
Sources: CPSC news releases of 12 Dec 2025 and 27 May 2026, CDC Carbon Monoxide Poisoning Basics, Ready.gov Power Outages, NFPA Generator Safety tip sheet.
A few more placement rules from NFPA, Ready.gov and the U.S. Fire Administration:
- Point the exhaust away from the building so fumes can't drift in through windows, doors or other openings.
- Don't stand or sit downwind of the exhaust. NFPA's line: if you can smell exhaust, you are inhaling it.
- Keep the generator dry and out of rain and flooding. Running one in a wet area can cause shock or electrocution.
- Plug appliances straight into the generator or into a heavy-duty, outdoor-rated extension cord with no cuts or tears and all three prongs.
- To connect a generator to the house wiring, have a qualified electrician install a properly rated transfer switch.
CO alarms: where and how many
An alarm is the only warning you get from a gas you can't sense.
What kind
Battery-operated, or plug-in with battery backup, so it keeps working in an outage. CPSC says interconnected alarms are best: when one sounds, they all sound.
CPSC: winter tips
Upkeep
Test monthly (CPSC). Check batteries when the clocks change in spring and fall, and replace the alarm per the maker's instructions or every 5 years (CDC).
CDC: CO basics
Symptoms of carbon monoxide poisoning
The CDC lists the most common symptoms. People often describe them as flu-like.
- Headache
- Dizziness
- Weakness
- Upset stomach
- Vomiting
- Chest pain
- Confusion
Infants, older adults and people with chronic heart disease, anemia or breathing problems are more likely to get ill. The CDC warns that people who are asleep, drunk or under the influence can die before they show any symptoms, which is one more reason to keep an alarm near the bedrooms.
Animals are affected too: Ready.gov notes carbon monoxide can kill you, your family and your pets.
Refuelling and storing gasoline
Gasoline brings a fire risk on top of the CO risk, so it gets its own routine.
01Refuel a cold engine
- Turn the generator off.
- Let it cool down before refuelling. NFPA: never refuel a generator while it is hot.
- The U.S. Fire Administration warns that gas spilled on a hot engine can cause a fire.
Source: NFPA Generator Safety tip sheet
02Use the right container
- Store fuel only in a container intended for it and labeled as such (NFPA).
- Never use plastic bags or other makeshift containers (CPSC).
- Put the cap back on after every use.
- At the gas station, set the can on the ground to fill it.
Source: CPSC Fuel Container Safety
03Store it away from the house
- Keep containers outside living areas (NFPA) in a cool, well-ventilated place (CPSC).
- Never store them inside the house or basement, or near fuel-burning appliances, open flames, pilot lights, stoves, heaters or electric mowers.
- Keep them out of reach of children.
- Never use gasoline to start or restart a fire.
Source: CPSC Fuel Container Safety
Questions people ask
How far from the house should a generator be?
At least 20 feet, with the exhaust pointed away from windows, doors and vents. CPSC, Ready.gov, the CDC and NFPA all use 20 feet.
Can I run a generator in the garage with the door open?
No. CPSC and the CDC both say never to use one in a garage, even with doors and windows open.
What are the first signs of carbon monoxide poisoning?
Headache, dizziness, weakness, upset stomach, vomiting, chest pain and confusion, per the CDC. Get outside and call 911.
Where should CO alarms go?
On every level of the home and outside sleeping areas, battery-powered or with battery backup.
Can I refuel a generator while it's running?
No. Turn it off and let it cool first. Spilled fuel on a hot engine can start a fire.
Can I store gasoline in the garage?
CPSC says never inside the house or basement or near ignition sources such as fuel-burning appliances, pilot lights and mowers. NFPA says outside living areas, in a labeled fuel container.
Read next
Sources
- CDC: Carbon Monoxide Poisoning Basics Symptoms, risk groups, yearly figures, generator distance, detectors.
- CPSC: Carbon Monoxide Information Center Get outside, then call 911. Alarm placement.
- CPSC: winter storm safety tips (12 Dec 2025) About 100 deaths a year, 20 feet, enclosed spaces, interconnected alarms, monthly tests.
- CPSC: hurricane season generator warning (27 May 2026) Exhaust away from windows, doors and vents.
- CPSC: Fuel Container, Gasoline and Other Liquid Fuel Safety Storing and handling gasoline.
- Ready.gov: Power Outages 20 feet from windows, doors and attached garages. Cool before refuelling.
- Ready.gov: Winter Weather Keep it dry, heavy-duty cords.
- NFPA: Generator Safety tip sheet (PDF) Distance measured to the building, exhaust, refuelling, fuel storage, transfer switch.
- U.S. Fire Administration: 5 Steps to Portable Generator Safety (PDF) Wet areas, spilled fuel on a hot engine.
- Poison Control (poison.org) 1-800-222-1222.