Generator carbon monoxide safety: where to put it and why

A portable generator is a small gasoline engine. Its exhaust contains carbon monoxide (CO), a gas you cannot see or smell. Federal safety agencies are blunt about the risk: the U.S. Consumer Product Safety Commission warns that the CO from a portable generator can kill you in minutes. Most generator deaths happen during and right after storms, when people run generators in garages, basements, or too close to the house.

The placement rules

Outside only. Never run a generator inside a home, garage, basement, crawl space, shed, or enclosed porch, even with doors and windows open. Fans and open garage doors do not clear CO fast enough.

Far from openings. The CDC advises keeping a generator more than 20 feet from any window, door, or vent. NFPA says to place it outdoors well away from doors, windows, and vents that could let CO come indoors. Farther is better. Point the exhaust away from the house and from neighbors’ homes.

Watch the wind. A generator placed upwind of an open window can still push exhaust inside. Close windows on the side of the house nearest the generator.

Keep it dry, but not enclosed. Rain can damage a generator and create a shock hazard. Use an open canopy-style cover designed for generators rather than moving it into a garage or under a closed porch.

CO alarms are not optional

Install battery-operated CO alarms, or plug-in alarms with battery backup, on every level of the home and outside sleeping areas. Test them before storm season. An alarm is the only warning you will get, because CO has no smell. Ready.gov lists CO alarms as a core part of outage preparation.

Know the symptoms

CDC lists the common symptoms of CO poisoning as headache, dizziness, weakness, upset stomach, vomiting, chest pain, and confusion. People who are asleep or have been drinking can die before they notice anything. If the alarm sounds or anyone feels these symptoms, get everyone outside to fresh air immediately and call 911. Do not go back in to turn off the generator.

CO shutoff features

Many newer portable generators include a sensor that shuts the engine off when CO builds up around it, designed to voluntary safety standards. Some also have lower-emission engines. These features help, but they are not a license to run a generator in a garage. Follow the placement rules no matter what the generator has.

Other generator hazards

• Backfeeding. Never plug a generator into a household outlet. Power can flow back into utility lines and injure line workers or neighbors. Use a transfer switch or interlock installed to code. See transfer switch vs interlock.
• Refueling. Turn the generator off and let it cool before adding fuel; spilled gasoline on a hot engine can ignite.
• Shock. Keep hands dry, do not run a generator in standing water, and use outdoor-rated cords in good condition.

A one-minute checklist

1. Generator outside, more than 20 feet from openings, exhaust pointed away.
2. CO alarms working on every level.
3. Cords outdoor-rated, no outlet backfeeding.
4. Engine off and cool before refueling.

Print the full outage prep checklist and keep it with the generator.