Carbon monoxide has no color, no smell, and it works fast. A portable generator can put out as much CO as hundreds of idling cars. Every year in the U.S., generator-related CO poisoning sends thousands of people to the emergency room and kills dozens, mostly in the days right after a storm.

Almost all of those deaths are preventable.

The rules that matter

  1. Never run a generator indoors. That includes the garage, the basement, a crawl space, a shed or an enclosed porch, even with doors and windows open.
  2. Keep it at least 20 feet from the house.
  3. Point the exhaust away from your home and your neighbors’ homes.
  4. Put battery-powered (or battery-backup) CO alarms on every floor and outside the bedrooms.
  5. Don’t sleep with a generator running nearby unless those alarms are working.

Where to put it

Outside, on flat dry ground, at least 20 feet from doors, windows and air intakes, and downwind of the house if you can manage it. Keep it away from your neighbors’ windows as well. If it’s raining, use a generator tent or canopy made for the purpose, which keeps it dry while letting air through.

Buy heavy-gauge, outdoor-rated extension cords that are long enough. Setting the generator close to the house because the cord is too short is one of the most common deadly mistakes.

Know the symptoms

CO poisoning is easy to mistake for the flu:

  • Headache
  • Dizziness
  • Weakness or tiredness
  • Nausea or vomiting
  • Shortness of breath
  • Confusion
  • Blurred vision

If several people in the house, or the pets, feel sick at the same time, think CO. Get everyone outside into fresh air straight away and call 911.

Picking a safer generator

Many newer portable generators have a CO sensor that shuts the engine off if gas builds up around it. Some are also designed to put out much less CO in the first place. Both are worth having, but they’re a backup, not a replacement for the rules above. And quieter inverter generators still produce deadly CO.

The indoor-safe option

Battery power stations don’t produce any exhaust, so they’re safe in bedrooms and apartments. A lot of households keep one for overnight and indoor needs, like the fridge, a CPAP and the internet, and only run a generator outside during the day. See power station vs. generator.

Other generator basics

  • Let the engine cool down before refueling. Gas spilled on a hot engine can catch fire.
  • Store fuel in approved containers, away from living areas.
  • Never backfeed the house through an outlet. Use a transfer switch installed by a licensed electrician.
  • Keep it dry, and don’t handle it with wet hands.

If a CO alarm goes off, don’t go looking for the source. Get everyone outside and call 911 or the fire department.