Portable Generator Safety: The Rules and the CPSC Data Behind Them

Portable generator safety comes down to one rule above all others: run the generator outdoors only, at least 20 feet from the house, with the exhaust pointed away from windows, doors and vents, and keep battery-powered carbon monoxide (CO) alarms on every level of the home. Never run it in a house, garage, basement, crawlspace, shed or on a porch, even with the doors open.^3,6 After that come three other hazards: shock (keep it dry and never connect it to house wiring yourself), fire (refuel only when the engine is off and cool) and overloading.

Every safety sheet repeats those rules. What they rarely show is why they are written that way. Below we pull the numbers out of CPSC’s records of 789 generator-related CO deaths from 2012 to 2022: where the generator was running, whether a window was open, whether a CO alarm was on the wall and what month it was.¹

Where generator CO deaths happen: what CPSC’s records show

Generators are the single product under CPSC’s jurisdiction linked to the most carbon monoxide deaths. CPSC estimates that generators alone were involved in 892 deaths from 2012 to 2022, or 41% of all non-fire CO deaths from consumer products it oversees.² Its CO center puts the number above 100 a year.³

Carbon monoxide is a colorless, odorless gas that can kill within minutes

CPSC staff complete an in-depth investigation for most of these deaths. Its latest generator report covers 553 deaths in houses, mobile homes and apartments. In 73% of them the generator was running inside the home itself, and in another 18% it was in an attached garage, an enclosed carport or an attached barn.¹

Rows are as CPSC published them in its Table 13; they add to 555 against a stated total of 553, a small discrepancy in the source. All counts are deaths reported to CPSC, which the agency calls a minimum, and 2021–2022 were still incomplete when the report was written.¹

Two details in the same report matter for anyone who thinks “just for a few minutes, in the next room” is safe. Of 440 home deaths where CPSC knew where the victim was, only 24% happened in the same room as the generator; the rest died elsewhere in the home. And the homes were small: the median was about 1,290 square feet, and 64% of the incidents were in homes under 1,500. CPSC says it is unclear whether that reflects income, faster CO buildup in a smaller space, or both.¹

Open doors, fans and venting the exhaust don’t make it safe

Opening the garage door or a window feels like ventilation. CPSC’s records show it isn’t. In 303 home deaths where investigators could tell whether anyone had tried to ventilate, 102 people (34%) died even though something had been done: windows or doors open (62 deaths), the generator set outside next to a window, door or air conditioner (25), or a fan or exhaust aimed out a window or door (15).¹

That answers a question people ask search engines every storm: running a generator in a garage with the door open, or trying to vent its exhaust out a window or door, is in the data as a way people died. The American Red Cross, which wrote its guidance with technical advice from CDC, NFPA and CPSC, says opening doors and windows or using fans will not prevent CO buildup.¹⁰

Where to put a portable generator

The 20-foot figure is the one the federal agencies agree on, and it is a minimum, not a target. Here is what each source actually says:

Sources: CPSC,⁶ CDC,⁷ Ready.gov,⁸ NFPA,¹¹ OSHA¹⁵ and Honda’s EG5000X owner’s manual.⁹

Twenty feet is not a guarantee. In 28 of the home deaths in Table 1, the generator was outdoors, usually near an open window or vent. In 2021, three people died with a generator that had a CO shut-off feature and was advertised as meeting the industry safety standard. It sat outside, under eaves with soffit vents into the attic, its exhaust pointed at a closed door; it did not shut off, and it ran until the tank was empty.¹ So keep it in the open, away from eaves, soffit vents and window air conditioners as well as doors and windows. A porch, covered patio or carport is a partly enclosed space, which Honda’s manual rules out.⁹

Do not enclose the generator in any structure.

CO alarms: the backup that was usually missing

A working CO alarm is the only thing in the house that can warn you, since you can’t see or smell the gas. In the generator deaths where CPSC could establish whether an alarm was present (159 of 789), 83% had no CO alarm at all. Of the 27 deaths where one was present, it was known to have sounded in only 8; in 14, its batteries were missing, dead or put in wrong.¹

What CPSC and CDC recommend:^5,7

• Type: battery-operated, or plug-in with battery backup, so the alarm still works when the power is out. A plug-in alarm with no battery is useless in an outage.
• Where: on every level of the home and outside sleeping areas. Not in attics or basements unless someone sleeps there. Interconnected alarms are best: when one sounds, they all sound.
• Upkeep: test monthly and replace the batteries every year (CPSC). Replace the alarm itself when the maker says, or every 5 years (CDC).

CO poisoning symptoms, and what to do

CPSC lists the symptoms as headache, dizziness, weakness, nausea, vomiting, sleepiness and confusion; CDC adds chest pain and notes they are often described as flu-like.^3,7 The danger is that people who are asleep or drunk may never notice them:

can die from CO poisoning before they have symptoms

If an alarm sounds or anyone feels sick while a generator is running, don’t look for the cause. Get everyone outside to fresh air immediately, then call 911.³

Generators with a CO shut-off

Some newer portable generators shut themselves off when CO builds up nearby. CPSC says models certified to the PGMA G300-2023 and UL 2201-2023 standards include CO safety technology, and that UL 2201 models also have reduced CO emissions.⁴ It is worth asking for when you buy. But the 2021 case above shows the limit: the feature is a backstop, not a reason to run the generator closer to the house.

Electrical hazards: shock, backfeed and cords

Plug appliances straight into the generator, or use a heavy-duty, outdoor-rated extension cord rated (in watts or amps) for at least the total of everything on it. Check the whole cord for cuts and make sure the plug has all three prongs, including the grounding pin.^10,11 Even a properly connected generator can overheat or fail when overloaded, the Red Cross warns, so stagger big loads,¹⁰ and check the size you need with our generator size calculator.

Never plug a generator into a wall outlet to power the house. The Red Cross calls this backfeeding: it can electrocute utility workers, your neighbors and your own household.¹⁰ Honda’s manual adds that the generator itself may explode, burn or start a fire when utility power comes back.⁹

Rain, snow and flooding

Water turns a generator into a shock hazard. Honda’s manual says not to expose it to rain or snow and not to operate it with wet hands.⁹ Ready.gov says to keep it dry and protected from rain or flooding, since touching a wet generator or anything connected to it can shock you.⁸ The Red Cross suggests a dry surface under an open, canopy-like structure, such as a tarp held up on poles.¹⁰

What you must not do is move the generator into the garage, onto the porch or under the eaves to keep it dry. That trades a shock risk for the CO pattern in Table 1. CPSC tells owners to follow the manufacturer’s instructions for wet weather,⁴ so check your manual before using any cover sold for running generators.

Refueling and storing fuel

Fuel spilled on hot engine parts can ignite, which is why Ready.gov, NFPA, OSHA and the Red Cross all say to turn the generator off and let it cool before refueling.^8,10,11,15 Honda’s manual adds the rest of the routine:⁹

• Stop the engine before you refuel.
• Handle fuel only outdoors, in a well-ventilated area, away from pilot lights, barbecues, sparks and flame.
• Wipe up any spilled fuel before you restart the engine.

None of the sources we checked gives a cooling time in minutes. Google’s AI Overview for “portable generator safety” credited OSHA with “at least 15 to 20 minutes” when we searched in October 2026, but OSHA’s fact sheet says only to shut the generator down “and allow it to cool.”¹⁵ Treat any specific number you see online as a rule of thumb, not official guidance.

Store gasoline in a container made and labeled for fuel, outside living areas, and not near a fuel-burning appliance such as a gas water heater in a garage. Local rules may limit how much you can keep; your fire department can tell you.^10,11 Honda also warns that gasoline can deteriorate within a few months, which causes hard starting, so keep only fresh fuel for the generator.⁹

Storm season: when the risk peaks

Generator CO deaths cluster in winter. CPSC counted 44% of them from November through February, often during ice and snow storms, and another 32% in March, April, September and October, when hurricanes and tropical storms drive many of the deaths.¹ Among outages with a known weather cause, hurricanes and tropical storms were linked to 55 deaths and ice or snow storms to 38.

Storms are not the whole story, though. CPSC also tracked why the generator was running:¹

The rules don’t change with the reason: a generator used every night in a home without power, or in a hunting cabin, is just as deadly indoors as one used during a hurricane. Before each storm season, run through this list:

1. 1

   Test every CO alarm

   Press the test button and put in fresh batteries if needed. CPSC asks for monthly tests and a yearly battery change.⁵

2. 2

   Read the manual again

   Check the generator, review its safety instructions and do the maintenance the manual asks for, as CPSC advises before hurricane season.⁴

3. 3

   Get fresh fuel

   Old gasoline causes hard starting. Honda says to drain the tank and refill with fresh gasoline if the generator has been stored for a year or more.⁹

4. 4

   Pick the spot and the cord

   Choose a dry, open spot at least 20 feet from doors, windows and vents, and an outdoor-rated cord long enough to reach it.^6,10

5. 5

   Plan your loads

   Decide what you will run at the same time, and confirm the generator can carry it. Our appliance wattage table lists running and starting watts.

6. 6

   Check on neighbors

   CPSC asks people to be a good neighbor and check on the people next door during extended power outages.⁶

In a winter outage, the furnace or heat pump blower needs power too; our guide to heat pump vs furnace running costs covers both systems. If you would rather not set up a portable unit in a storm at all, our calculator page compares portable and standby generators. For the rest of our backup-power guides, see the generators section and the wider home energy section. Our editorial policy explains how we choose sources, and our estimates and safety disclaimer sets the limits of pages like this one.