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.

How serious the risk is

The CDC calls carbon monoxide an odorless, colorless gas that "kills without warning." It reports that each year more than 400 Americans die from unintentional CO poisoning not linked to fires, more than 100,000 visit an emergency department, and more than 14,000 are hospitalized. Portable generators are one of the household sources the CDC specifically names. Many generator-related poisonings happen during and after storms, when people are tired, stressed, and running equipment in unfamiliar ways.

Who is most at risk

The CDC says everyone is at risk, but infants, older adults, and people with chronic heart disease, anemia, or breathing problems are more likely to get sick. People who are asleep or intoxicated can die before they notice any symptoms. That's why a CO alarm, not your senses, is the real safeguard.

Where to put the generator, specifically

The CDC's guidance is to use generators only outside, more than 20 feet from any windows, doors, and vents. Ready.gov gives the same distance and adds attached garages. Practical points:

• Never in a garage, even with the door open. CO can build up quickly and seep into the house.
• Never on a porch or under a carport against the house, and never in a crawl space or basement.
• Point the exhaust away from the house and from neighbors' homes.
• Check the wind. Exhaust can drift toward windows on the downwind side.
• Mind your neighbors. In dense neighborhoods, your generator's exhaust can reach the house next door. Talk with neighbors about placement.

CO alarms: placement and maintenance

The CDC recommends battery-operated or battery-backup CO detectors near every sleeping area. Ready.gov recommends them on every level of the home. Additional CDC advice:

• Check the batteries twice a year, for example when the clocks change.
• Replace the detector according to the manufacturer's instructions, or every five years.
• Consider a model with a digital readout, which can show the highest CO level recorded.

During an outage, plug-in alarms without battery backup won't work, so make sure yours have batteries.

Know the symptoms and act fast

The CDC lists headache, dizziness, weakness, upset stomach, vomiting, chest pain, and confusion as the most common symptoms. They're often described as "flu-like." If several people or pets in the home feel sick at the same time, especially when a generator or other fuel-burning device is running, suspect CO.

If you suspect CO poisoning or your alarm sounds:

1. Get everyone, including pets, outside into fresh air immediately.
2. Call 911 or your local emergency number.
3. Don't go back inside until emergency responders say it's safe.
4. Turn off the generator only if you can do so without re-entering a contaminated area.

Report generator poisonings

The CDC encourages people who've had a poisoning incident related to any generator to report it to the U.S. Consumer Product Safety Commission. Reports help regulators track dangerous products and patterns.

Weather-protecting a generator safely

Rain is a common reason people move generators into garages. Instead, use a generator tent or cover designed for operating units, which keeps rain off while allowing airflow around the engine and exhaust. Never fully enclose a running generator. Keep it on a dry, level surface, as Ready.gov notes, because a wet generator can also cause electric shock.