One Monday morning in April 2019, 38-year-old Dustin Patch called in sick to Big City Motors in Sioux Falls, S.D., where he worked as a finance officer. The week before, he'd been complaining of headaches.

Patch, who lived in nearby Hartford, had recently purchased a portable generator so that he could keep a sump pump running in his basement. Severe storms had caused flooding and power outages throughout the spring. He had set up his new generator in the attached garage. 

A divorced father, Dustin shared custody of four young boys, though none were with him the night before he called in sick. That morning his two older sons stopped by to grab their bikes and ride to school, and according to Dustin's mother, Sharon, he told them he didn't feel well.

After school, his eldest son, Gavin, then 12, found his father collapsed on the stairway from the kitchen to the garage. First responders pronounced him dead at the scene, and a death certificate would state that Dustin Patch died of carbon monoxide poisoning due to operating a generator inside. 

"His basement had flooded just a few weeks earlier, and he was probably just working in a hurry because he didn't want it to happen again," Sharon Patch says. "He lived for those four boys, and he was such a good father."

How to Run a Generator Safely

A Silent Killer

Portable generators have long concerned safety advocates because their engines emit carbon monoxide (CO) at a high rate, and people might not be aware of the hazard posed by the deadly gas, which is colorless, odorless, and tasteless. From 2005 to 2017, more than 900 people died of carbon monoxide poisoning while using portable generators, according to the Consumer Product Safety Commission, and about 15,400 people were sickened enough to require treatment at an emergency room. 

More on generators

"Carbon monoxide is called the silent killer not only because it's undetectable by the senses but because of the sequence in which it kills you," says David Farcy, MD, an emergency room physician in hurricane-battered Florida and president of the American Academy of Emergency Medicine. "While lower-level exposure might make you feel sick, at higher levels it can incapacitate you, not unlike excessive drinking. Many people fall asleep completely shortly before dying from the effects of the gas." 

For many people, generators are emergency equipment they use during power outages—desperate circumstances in which they don't always remember to follow safety guidelines. But like any other machine or tool with an engine, a generator should never be operated in an enclosed space.

That goes for 2,000-watt units you might use for a tailgate party to 8,000-watt models on wheels that can power an entire house. (Home standby generators also produce carbon monoxide, but they don't pose the same threat because they're permanently installed outdoors and are typically subject to building codes designed to ensure safety.) 

In about 93 percent of the deaths reported to the CPSC, the generator was inside the victim's living space. And in cases where the agency has data, there was an attempt to vent the exhaust outside about one-third of the time by cracking open a window or opening a garage door, or even with makeshift ductwork.

At one point before he died, Dustin Patch had been running his generator in the garage with the garage door cracked open, according to his mother. That's not even remotely safe. Consumer Reports' tests to re-create this scenario recorded dangerous CO levels.

New Safety Technology

To reduce the risk of carbon monoxide poisoning, some new generators feature a built-in sensor that triggers an automatic shutoff if the gas builds up to dangerous levels in an enclosed space, and some also have engines that emit less CO in the first place.

Recent CR test data show that these safety features are likely to save lives. That's why we've revamped our portable generator ratings to reward models that have new safety features—and penalize those that don't. Consumer Reports no longer recommends any portable generator that doesn't include at least one of these safety features. 

"We believe safety technology is critical for portable generators, and as an organization we can no longer recommend any model that doesn't have some form of it," says Liam McCormack, CR's vice president of research, testing, and insights. "We're incentivizing the industry to move in the right direction, as we have in the past with innovative lifesaving features on cars, such as electronic stability control, which is now standard. The goal is to achieve broad adoption of effective generator safety technology, as we believe every consumer should have access to safe products."

But our findings also revealed potentially life-threatening gaps that an automatic shutoff fails to address. When we ran an experiment simulating someone using a portable generator in the doorway of a garage—with the door open in an attempt at ventilation but with the exhaust directed inward—all five generators failed to shut off as CO quickly built up to unsafe levels. 

"It's foreseeable that a homeowner could end up using a generator in an attached garage with the garage door open," says John Galeotafiore, an associate director for testing at CR. "After all, a generator shouldn't get wet, yet power outages often occur during rain or snowstorms. If a person doesn't have a canopy to protect his generator, we can imagine why he might mistakenly think it's safe to run it near an open garage door." 

It's not. With any generator, you should follow these three rules: Never run it indoors or in an enclosed space, always run it at least 20 feet away from your house, and always direct the exhaust away from any occupied space.

If you're shopping for a generator, look for marketing terms such as "CO Guard," "CO Protect," "CO Detect," "CO Shield," or "CO Sense." To verify whether a generator meets one of two voluntary standards the industry follows, check the packaging for one of these references:

• ANSI/UL2201 Certified for Carbon Monoxide Safety

• ANSI/PGMA G300 Certified Safety & Performance 

Each standard specifies a peak level and a lower level for sustained exposure to the gas, which relates to the technology and how CO affects human physiology.

Symptoms like headaches and dizziness generally occur at CO levels from 70 to 150 parts per million (ppm), which a typical generator can produce in minutes. You can die from sustained levels above 150 to 200 ppm, according to the CPSC's safety guide on carbon monoxide. Our testing revealed differences in how safety features work based on which standard a generator meets.

Generator Safety Technology at Work
Here's a simulation of CO emissions building up in an enclosed space from two different portable generators. One has an automatic CO shutoff; the other doesn't.
Auto Shutoff
No Shutoff
PPM = Parts per million
By Andy Bergmann

Competing Standards

One standard was created by the Portable Generator Manufacturers' Association (PGMA), a trade group, and approved by the American National Standards Institute (ANSI). For a generator to meet the PGMA standard, it must have a shutoff mechanism that automatically stops the engine before carbon monoxide reaches 800 ppm or the average exceeds 400 ppm over any 10-minute period. "Our standard came about after a review of CPSC data that showed nearly all deaths associated with carbon monoxide from generators occurred in enclosed spaces or indoors," says Joe Harding, technical director at PGMA. "It's been tested in thousands of simulations and is designed to protect consumers and prevent nearly all deaths."

The other safety standard comes from UL. For a generator to meet the UL 2201 carbon monoxide safety standard, in addition to having an automatic shutoff its engine must significantly reduce carbon monoxide emissions. UL's shutoff levels are lower than PGMA's: a 150 ppm average during a 10-minute period or a peak of 400 ppm. It's a belt-and-suspenders approach that so far has been adopted by both Techtronic Industries (TTI), which makes brands including Ryobi, and Echo. 

Michael Gardner, TTI's vice president of new product development, says the company's rationale is based on a broad view of the risk. "Our review of the data led us to believe that after a hurricane, many people are running a generator for 24 hours a day—and often in close proximity to the house to prevent it from being stolen," he says. "That realization led us to conclude we needed to develop generators that addressed the perils of outdoor use, too. And that automatic CO shutoffs alone weren't enough." 

Generator Safety Standards
Under both the PGMA and UL standards, an automatic shutoff kicks in if CO, measured in parts per million, reaches a certain limit, or if the average exceeds a lower limit over any 10-minute period.

The CPSC is reviewing data on both standards to determine whether compliance with either, or some combination of the two, will adequately protect consumers. In the meantime, because the standards are voluntary, it's entirely up to manufacturers to comply with one or the other—or neither. 

Gardner told CR that going forward, all of TTI's new generators will be equipped with one safety feature or more to mitigate the risk of CO poisoning. Generac told CR that it has introduced nine new models with an automatic CO shutoff. "Generac is committed to the safety of all portable generator users," says Ryan Schmitt, its product manager for portable generators and accessories. 

Consumer Reports says that having two separate standards isn't ideal. 

"Manufacturers now have two voluntary safety standards intended to help reduce the CO hazard," says William Wallace, CR's manager of home and safety policy. "Ultimately, to best protect consumers, there should be a single, stronger standard enforced by the Consumer Product Safety Commission."

3 Generators With CO Safety Features

Price: $850

CO safety technology
Power delivery
Power quality

CR's take: This modestly sized generator from Echo weighs in at just 86 pounds but produces 3,400 watts. It delivers reliable power, with a rating of Excellent for power delivery. It has an electric start, and an app lets you monitor the load on the generator from your phone—you even get an estimate of how long the generator will run based on how much fuel is in the tank. It has a CO safety shutoff and is designed to produce less CO. It runs up to 23 hours on a tank of gas. 

Price: $1,150

CO safety technology
Power delivery
Power quality

CR's take: This Lowe's exclusive generator from Cat puts out 8,000 watts of power and runs an impressive number of hours on a single tank of gas—up to 18—helping it earn a rating of Very Good for that test. It provides steady, reliable power, and features an electric start. It has a built-in CO safety shutoff.

Price: $1,050

CO safety technology
Power delivery
Power quality

CR's take: For slightly less money than the Cat above, this competent DeWalt produces an impressive 8,000 watts, with a run time of up to 17 hours on a single tank of gas. It has a built-in CO safety shutoff. And it provides steady, reliable power, earning a rating of Very Good in power quality.