Consumer Product Safety Commission Report: Portable Generator UL Standard Can Reduce Risks of Carbon Monoxide Poisoning

UL Standards & Engagement
  • Media Coverage

February 28, 2022


two men working on a power generator

On Feb. 23, the U.S. Consumer Product Safety Commission (CPSC) announced the publication of a staff report that determined UL 2201, the Standard for Safety for Carbon Monoxide (CO) Emission Rate of Portable Generators, would avert nearly 100% of deaths from carbon monoxide poisoning in testing scenarios that were based on CPSC data of fatal incidents with non-compliant generators in enclosed spaces. 

In 2018, Underwriters Laboratories published the second edition of UL 2201 with updated requirements to help mitigate CO poisoning hazards. In order to comply with the requirements, a generator must produce a low emission rate, and it must also be equipped with a CO sensor that will automatically shut the unit off if certain concentrations of CO are detected. 

In conducting its tests to determine the effectiveness of UL 2201 and other voluntary standards for portable generator safety, the CPSC staff coordinated with the National Institute for Standards and Technology (NIST) to perform approximately 140,000 simulations that replicated 511 fatalities in the CPSC database. Thirty-seven different house models and three detached garage models were used in the simulations, with variations in generator locations, generator sizes, and weather conditions. 

The analysis found that generators compliant with the UL 2201 standard would avert nearly 100% of the deaths that occurred with the current, non-compliant generators... - U.S. Consumer Product Safety Commission (CPSC) 1

The CPSC report notes that even after an automatic shutoff in an enclosed area, a consumer may try to restart the generator without relocating it. For this reason, the generator in each simulation was restarted after shutting off. If it was located indoors and it stopped again, it was restarted a second time outdoors and allowed to run until its full fuel tank was empty. Concentrations of CO in each room were used to calculate carboxyhemoglobin (COHb) levels for the theoretical home occupants. In nearly every case, generators that conformed to UL 2201 prevented COHb levels from reaching a fatal threshold. Of all 140,000 simulations, only three of the theoretical occupants would have required hospitalization and 22 would have required medical treatment with subsequent release.

In addition to analyzing the effectiveness of voluntary standards in addressing CO hazards from portable generators, the CPSC staff also performed a review of compliance for current products in the marketplace. The report concludes that while the Standard is effective at mitigating CO hazards from portable generators, there is not currently a high level of compliance among manufacturers for products available to consumers. The staff report therefore supports a mandatory rulemaking process on portable generators and proposes to include the delivery of a rulemaking briefing package to the CPSC in its Fiscal Year 2023 Operating Plan.