Portable generators kill people every winter and after every hurricane, and the cause is almost always the same. It is not electrocution and it is not fire. It is carbon monoxide, produced by an engine that someone put too close to the house because it was raining.
Why CO is so dangerous here
Carbon monoxide is colourless, odourless and slightly lighter than air. It binds to haemoglobin with roughly 200 times the affinity of oxygen, so it displaces the oxygen your blood is carrying rather than merely diluting it. The early symptoms of carbon monoxide poisoning are headache, dizziness, nausea and confusion, which read as flu, or as ordinary exhaustion during a storm cleanup. Confusion is the cruel part: by the time it sets in, the judgment needed to walk outside is already impaired.
A single portable generator can produce as much carbon monoxide as hundreds of idling cars. That is the number worth remembering when you are deciding whether the covered porch is close enough.
The placement rules
The U.S. Consumer Product Safety Commission's guidance is short and specific: run portable generators outdoors only, at least 20 feet from the house, with the exhaust pointed away from doors, windows and vents. Their consumer sheet, What to Know About Generators and Carbon Monoxide, is one page and worth printing for the garage wall.
Places that are never acceptable, no matter the weather:
- Inside a garage, attached or detached, with the door open or closed
- On a porch, in a carport, under a deck or in a breezeway
- In a basement, crawlspace, shed or any partially enclosed space
- Under an open window, next to a dryer vent, or beside a fresh air intake
- In a window well or a stairwell where exhaust can pool
Opening a door or a window does not fix any of these. The CPSC is explicit that ventilation of that kind does not prevent lethal buildup, because engine exhaust is produced far faster than passive airflow can clear it.
What about rain?
This is the real question, because "keep it outside" collides with "do not run it wet" during exactly the weather that caused the outage. The answer is a purpose-built generator tent or an open-sided canopy that keeps rain off the unit while leaving all four sides open to the air. These cost a fraction of the generator and remove the temptation that kills people. A tarp draped over the machine is not the same thing and can trap both heat and exhaust.
CO shutoff sensors: useful, not a licence
Newer portable generators sold in the United States increasingly include a CO sensor that shuts the engine down when concentrations climb, built to voluntary standards developed after the CPSC documented the death toll. If you are buying a portable, buy one with this feature. It has measurably saved lives.
It is still a backstop, not a permission slip. The sensor protects against the scenario where you did everything right and the wind changed. It does not make a garage safe. Treat it the way you treat a seatbelt: it improves the odds in an accident, it does not make the accident acceptable.
Alarms inside the house
Working CO alarms are the second line of defence and the cheapest safety equipment you will ever buy. Install battery-powered or battery-backed alarms on every level of the home and outside every sleeping area, test them at the start of storm season, and replace the whole unit at the end of its stated service life, which is typically five to ten years. The sensing element degrades whether or not the alarm has ever sounded. The U.S. Fire Administration's carbon monoxide prevention guidance covers placement in detail.
If an alarm sounds during an outage: get everyone outside into fresh air first, then call the fire department from outside. Do not open windows and go back to sleep, and do not spend time trying to identify the source.
Refuelling, which is the other way generators hurt people
Shut the engine off and let it cool before adding fuel. Gasoline spilled onto a hot muffler or cylinder head ignites, and the fire starts at the fuel can in your hands. Store fuel in approved containers, outside living space, away from any appliance with a pilot light, and never in the same enclosed space as the running generator.
The one-minute pre-start check
- At least 20 feet from the house, exhaust pointed away from every opening.
- Not in or under anything with more than a roof; four sides open.
- Dry footing, or a canopy rated for the job. Dry hands.
- Oil level checked. Fuel added with the engine off and cool.
- CO alarms inside tested and working.
- Cords rated for the load, undamaged, uncoiled and not run under a door.
Six checks, one minute, every single time. The households that get hurt are not the ones that never knew the rules. They are the ones that followed them for three days and then made an exception on night four.