TL;DR: Ameren Illinois says keep generators outside and never plug them into a wall outlet.

TL;DR: Ameren Illinois held a generator safety demonstration in West Peoria on Sept. 16, 2026, warning homeowners to run generators outside in ventilated areas and never plug them directly into home outlets because of carbon monoxide and backfeed risks, according to 25News Now.

Why Ameren Illinois Issued The Warning Now

Ameren Illinois is reminding homeowners to use backup generators safely following a storm season that brought widespread severe weather and power outages across the state, according to 25News Now.

The utility held a generator safety demonstration Wednesday in West Peoria, focusing on the dangers of improper generator use and electrical backfeed, according to 25News Now.

The demonstration comes after a spring and summer that brought repeated rounds of severe weather across Illinois, resulting in widespread outages and damage to electrical infrastructure, according to 25News Now.

Ameren says homeowners who rely on generators during outages should prepare in advance, understand how their equipment works, and have qualified professionals install their electrical equipment, according to 25News Now.

Portable generators provide options when permanent power is unavailable, including after storms, but they also introduce overlooked hazards, according to Electrical Contractor Magazine.

Federal safety information cited in a HomeGridUp generator safety guide states that most portable generator incidents reported to the U.S. Consumer Product Safety Commission involve carbon monoxide poisoning from generators used indoors or in partly enclosed spaces.

Where To Place A Portable Generator

Jake Dukett, Ameren Illinois's supervisor of public awareness, said one of the first things homeowners should consider is where they place a generator, according to 25News Now.

Generators should be operated outside in a well-ventilated area so exhaust does not enter a home, according to 25News Now.

Dukett said Ameren has heard from first responders about carbon monoxide calls in outage areas, where generator exhaust entered homes, according to 25News Now.

For homeowners using portable generators during an outage, Dukett said the key is to understand the equipment before an emergency happens, according to 25News Now.

He said generators should remain outside and away from areas where exhaust could enter the home, and electrical cords and connections should be used only as recommended by the manufacturer, according to 25News Now.

Proper placement is the single most effective way to prevent carbon monoxide poisoning, according to Electrical Contractor Magazine.

That publication states that generators should always be operated outdoors in open, well-ventilated locations where exhaust cannot migrate into occupied spaces through doors, windows, vents or HVAC intakes.

Wind direction should also be considered, particularly on large commercial projects where exhaust can be carried toward occupied work areas, according to Electrical Contractor Magazine.

If possible, generators should be positioned well away from buildings while still allowing safe cord routing and equipment protection, according to Electrical Contractor Magazine.

Workers should recognize that carbon monoxide can travel farther than expected, and safe placement requires considering where the generator sits and where exhaust gases may ultimately accumulate, according to Electrical Contractor Magazine.

How Far From Doors, Windows And Vents

The HomeGridUp generator safety guide states that the Consumer Product Safety Commission says to put the generator outdoors, far from doors, windows and vents that could let carbon monoxide come inside, and to point the exhaust away from nearby buildings.

The same guide states that the Centers for Disease Control and Prevention advises using generators outside only, more than 20 feet away from any windows, doors and vents.

The guide also states that the National Fire Protection Association advises at least 20 feet from all doors, windows and vent openings, measured from the generator to the building.

The Occupational Safety and Health Administration guidance cited in that guide calls for 3 to 4 feet of clear space on all sides of the generator and above it so it gets enough air.

Distance alone is not the whole rule, because the guide states that OSHA says not to use a generator outdoors if its spot near doors, windows and vents could let carbon monoxide build up inside.

The guide states that NFPA advises people not to stand or sit downwind of the exhaust, explaining that if exhaust can be smelled, it is being breathed.

Why Indoor Or Garage Operation Kills

A big risk associated with portable generators is carbon monoxide, an invisible, odorless and potentially deadly gas produced whenever gasoline, diesel, propane or natural gas engines operate, according to Electrical Contractor Magazine.

That publication describes carbon monoxide as "the silent killer."

When inhaled, carbon monoxide prevents the blood from carrying enough oxygen throughout the body, according to Electrical Contractor Magazine.

Early symptoms of carbon monoxide poisoning can include headache, dizziness, fatigue, nausea and confusion, according to Electrical Contractor Magazine.

Those indicators often get confused with heat stress, dehydration or general fatigue, according to Electrical Contractor Magazine.

Prolonged exposure can quickly lead to unconsciousness and death, according to Electrical Contractor Magazine.

It takes four to six hours to exhale about half of the inhaled carbon monoxide in the blood, and giving the person 100% oxygen can speed this up some, according to Electrical Contractor Magazine.

A common misconception is that opening doors or windows provides adequate ventilation, according to Electrical Contractor Magazine.

OSHA specifically warns that generators should never be operated inside buildings, garages or partially enclosed areas because dangerous concentrations of carbon monoxide can accumulate rapidly, according to Electrical Contractor Magazine.

The HomeGridUp guide states that CPSC says never to use a generator inside a home, garage, basement, crawlspace, shed or similar area, even when using fans or opening doors and windows for ventilation.

That guide states that CPSC says deadly carbon monoxide levels can build up quickly in these spaces and can linger for hours, even after the generator shuts off.

The guide states that OSHA gives the same list of prohibited indoor locations and says open windows and doors may not prevent carbon monoxide from building up when a generator is in an enclosed space.

The guide states that NFPA says never to use one in an attached garage, even with the door open.

What Backfeed Is And Why It Endangers Line Workers

Another major concern highlighted by Ameren Illinois is electrical backfeed, according to 25News Now.

Dukett said backfeed can occur when a generator is improperly connected to a home's electrical system, including when someone plugs a generator directly into an outlet, according to 25News Now.

Electricity can then travel from the home back toward the utility system, according to 25News Now.

Dukett explained that the electricity can reach a transformer, which can increase the voltage and send power back onto utility lines, according to 25News Now.

Those lines may appear to be de-energized to crews working to restore power, according to 25News Now.

"If we don't install those generators correctly, then it can come through the house system back into the service line," Dukett said, according to 25News Now.

He said that current can hit a transformer and kick the voltage back up to line voltage on the power lines, according to 25News Now.

He said that creates a danger for utility workers, contractors and members of the public, and in some cases could cause serious injury or death, according to 25News Now.

Dukett said one of the most common mistakes Ameren sees is homeowners plugging generators directly into an electrical outlet, believing that will safely power the home, according to 25News Now.

He said that type of connection can instead create the conditions for backfeed, according to 25News Now.

Backfeeding is another critical concern because connecting generators directly into building wiring without an approved transfer switch can energize utility lines, placing workers and emergency responders at risk of electrocution, according to Electrical Contractor Magazine.

Proper transfer equipment and lockout/tagout procedures are critical whenever temporary generators are connected to existing electrical systems, according to Electrical Contractor Magazine.

The HomeGridUp guide states that CPSC says never to try to power house wiring by plugging the generator into a wall outlet.

That practice is called backfeeding, and CPSC calls it extremely dangerous, according to that guide.

The guide states that backfeeding can electrocute utility workers and neighbors served by the same transformer, and it bypasses some of the home's circuit protection.

How To Connect Power Without Backfeeding

Ameren recommends having a qualified professional install generators whenever possible, according to 25News Now.

Dukett said homeowners should use proper isolation equipment, ensure the home is separated from the utility system, and understand how the generator is designed to operate, according to 25News Now.

Ameren also emphasized disconnecting the home from the utility system to help prevent backfeed, according to 25News Now.

OSHA says never to attach a generator to a building's wiring unless a qualified electrician has installed it with a transfer switch, according to the HomeGridUp guide.

That guide states that NFPA says that switch must be properly rated and installed to the National Electrical Code and local codes.

OSHA recommends plugging equipment directly into generator-mounted receptacles whenever practical or using heavy-duty extension cords rated for the intended load and outdoor use, according to Electrical Contractor Magazine.

As always, cords should be inspected before each use and removed from service if damaged, according to Electrical Contractor Magazine.

Improper grounding, damaged cords, wet conditions or incorrect connection methods can expose workers to serious electrical hazards, according to Electrical Contractor Magazine.

Fuel, Fire And Wet-Weather Precautions

He also recommended having permanent backup generators inspected and maintained regularly by a qualified technician, according to 25News Now.

Portable generators also present fire hazards because they combine hot engine components with flammable fuels, according to Electrical Contractor Magazine.

Generators should always be shut down and allowed to cool before refueling, according to Electrical Contractor Magazine.

Spilled gasoline contacting hot engine components can ignite almost instantly, according to Electrical Contractor Magazine.

Fuel should be stored only in approved containers and away from ignition sources, according to Electrical Contractor Magazine.

Contractors should also avoid overloading generators, which can lead to overheating and equipment damage, according to Electrical Contractor Magazine.

Routine maintenance, including checking fuel lines, exhaust systems and the engine condition, should also be done because it reduces fire and carbon monoxide hazards, according to Electrical Contractor Magazine.

The HomeGridUp guide states that CPSC says to turn the generator off and let it cool down before refueling, because gasoline spilled on hot engine parts could ignite.

That guide states that OSHA notes generators stay hot for long periods after they stop.

The guide states that CPSC says never to store generator fuel in the home.

The guide states that gasoline, propane and kerosene should be kept outside living areas in properly labeled, non-glass safety containers, and not near a fuel-burning appliance such as a gas water heater in a garage.

CPSC warns that generators can shock or electrocute people, especially in wet conditions, according to that guide.

If a generator must run when it is wet outside, CPSC says to operate it under an open, canopy-like structure on a dry surface where water cannot reach it or puddle or drain under it, according to that guide.

That guide states that hands should be dried before touching a generator, and the generator should be protected from moisture without running it indoors or near openings to the house.

Alarms, Symptoms And Emergency Response

In recent years, many employers have begun incorporating portable carbon monoxide monitors into their safety programs because they provide continuous air monitoring and audible alarms when concentrations begin to rise, according to Electrical Contractor Magazine.

OSHA recommends carbon monoxide detectors or monitors wherever exposure hazards may exist, especially in enclosed or partially enclosed work environments, according to Electrical Contractor Magazine.

Workers should never ignore monitor alarms or assume symptoms are unrelated to carbon monoxide exposure, according to Electrical Contractor Magazine.

If elevated levels are detected, work should stop immediately, affected personnel should move to fresh air and the source of exposure should be identified before operations resume, according to Electrical Contractor Magazine.

The HomeGridUp guide states that CPSC says to install battery-operated carbon monoxide alarms, or plug-in alarms with battery backup, following the maker's instructions, and to test the batteries monthly.

That guide states that CDC says anyone using a generator should have a battery-powered or battery-backup carbon monoxide detector in the home.

That guide states that CPSC calls for alarms on every level of the home and outside sleeping areas, and that alarms should be certified to a current safety standard such as UL 2034.

CDC lists the most common symptoms as headache, dizziness, weakness, upset stomach, vomiting, chest pain and confusion, according to that guide.

That guide states that CDC says infants, older adults and people with chronic heart disease, anemia or breathing problems are more likely to get sick from carbon monoxide.

If someone starts to feel sick, dizzy or weak while a generator is running, CPSC says to get to fresh air right away without delay, according to that guide.

If the carbon monoxide alarm sounds or poisoning is suspected, that guide states that people should get outside immediately, then call 911, with CDC also listing Poison Control at 1-800-222-1222.

That guide states that OSHA says not to go back inside until trained, properly equipped responders say it is safe.

Electrical workers should also receive training that includes safe generator placement, carbon monoxide hazard recognition, proper grounding and bonding requirements, transfer switch operation and fuel handling procedures, according to Electrical Contractor Magazine.

They should be educated on electrical load management and emergency response procedures and understand that symptoms of carbon monoxide poisoning can affect judgment, making self-recognition difficult, according to Electrical Contractor Magazine.

Sources referenced