Portable Generator Safety: The Carbon Monoxide Rules That Save Lives

Direct answer: Carbon monoxide is a colorless, odorless gas that can kill within minutes — and portable generators are one of its deadliest sources. The rule from the CDC and the U.S. Consumer Product Safety Commission is simple: never run a generator inside your home, garage, basement, carport, or near doors, windows, or vents. Generators belong outdoors only, more than 20 feet from the house, with the exhaust pointed away.

Why generators are so dangerous

The CPSC warns that carbon monoxide is "a colorless, odorless gas that can kill within minutes, often before victims recognize symptoms." A generator's danger is not obvious: the CO emission rates of almost all engine-driven portable generators are "extremely high, on the order of hundreds or greater times the CO emission rates of cars," according to the CPSC. The CDC notes that carbon monoxide "kills more than 500 Americans each year."

The death toll from generators alone is staggering. The CPSC had reports of at least 1,332 carbon monoxide poisoning deaths linked to portable generators from 2004 through 2021 — and staff estimated 77,658 medically attended nonfatal CO injuries in the same period. Generator deaths in 2020 were likely to exceed the highest annual total previously reported (103 in 2005). Where were those generators? In 70 percent of the deaths in fixed-structure homes, the generator was used inside the home's living area; in 25 percent, it was inside the garage.

The 20-foot rule

The CDC's exact instruction: "Only use generators outside, more than 20 feet away from any windows, doors, and vents." The CPSC says the same: "Operate generators outdoors only, at least 20 feet from homes and buildings, with exhaust directed away from windows, doors and vents." Two things people get wrong:

Opening doors or windows does not make it safe. The CDC says never use a generator inside your home or garage, "even if doors and windows are open." The CPSC agrees: opening doors or windows "does not provide enough ventilation to prevent the buildup of lethal levels of CO." Generators produce lethal levels of carbon monoxide even with the garage door up — and the CPSC adds that an outside porch or carport is too close to the home. Never run your car or truck inside a garage attached to a house, even with the garage door open.

Never burn fuel indoors

The rules extend beyond generators. The CDC says never use a generator, charcoal grill, camp stove, or other gasoline- or charcoal-burning device inside your home, basement, or garage — or outside less than 20 feet from a window, door, or vent. "Never burn charcoal indoors." "Never use a portable gas camp stove indoors." And do not heat your house with a gas oven.

Detectors and what to do when one sounds

Install a battery-operated or battery backup carbon monoxide detector in your home — the CPSC recommends battery-operated smoke and CO alarms, or alarms with battery backup, on each level of the home and outside separate sleeping areas. The CDC says to check or replace the battery when you change your clocks each spring and fall. If the detector sounds, leave your home immediately and call 911.

Know the warning signs. The CDC says to seek prompt medical attention if you feel dizzy, light-headed, or nauseated and suspect CO poisoning. Because the gas is invisible and has no smell, you cannot rely on sensing it — rely on distance, detectors, and the rule: outside, 20 feet, exhaust away.

Related pages on this site: the Hurricane Safety Guide (storms cause the outages that cause the poisoning), US weather alerts by state, and the history of major storms.

Frequently asked questions

How far should a portable generator be from the house?

More than 20 feet from any windows, doors, and vents, outdoors only, with the exhaust directed away from the home and any building someone could enter. (CDC and CPSC)

Can I run a generator in the garage if the door is open?

No. The CDC says never use a generator inside your home or garage, even with doors and windows open. In 25% of generator deaths in fixed-structure homes, the generator was inside the garage; in 70%, it was inside the living area. (CPSC)

What are the symptoms of carbon monoxide poisoning?

The CDC says to seek prompt medical attention if you feel dizzy, light-headed, or nauseated and suspect CO poisoning. CO is colorless and odorless and can kill within minutes, often before victims recognize symptoms. (CPSC)

What should I do if my CO detector alarm sounds?

Leave your home immediately and call 911. Install battery-operated or battery-backup CO detectors on each level of your home and outside separate sleeping areas, and check the batteries when you change your clocks in spring and fall. (CDC, CPSC)

Sources

• CDC - Carbon Monoxide Poisoning Basics
• CDC Media Statement - Carbon Monoxide Poisoning, Jan 5 2018
• CPSC - Generator, Carbon Monoxide and Fire Hazards Warning 2026
• CPSC - Hurricane Milton Warning: Protect Your Family from CO Poisoning
• CPSC - Draft Supplemental Notice of Proposed Rulemaking, Portable Generator Safety Standard
• CDC - Natural Disasters PSA Toolkit: Avoiding Carbon Monoxide Poisoning

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