Minnesota Attorney General Keith Ellison is urging the federal government to investigate the health risks of gas kitchen stoves, which have been linked to indoor air pollution and childhood asthma by peer-reviewed academic research and environmental groups.

Ellison and a handful of other states' top lawyers asked the Consumer Product Safety Commission (CPSC) this month to "take action that would reduce the health hazards posed by these appliances," including public education efforts and better ventilation requirements in homes where the stoves are installed.

A long-simmering discussion on the risks of cooking with gas burst into public view earlier this year. In January, Richard Trumka Jr., a CPSC commissioner, told Bloomberg News that the agency was considering several regulations for the appliances, including banning the sale of new stoves. Trumka walked back his remarks in subsequent interviews, but the CPSC did solicit comments on how it should regulate gas cooktops in the future.

In Minnesota, 29% of the stoves in full-time homes are fueled with natural gas, according to 2020 data from the Energy Information Administration, while the national average is 38%.

In an emailed statement, Ellison noted that federal agencies have long known gas stoves could create indoor pollution that would be considered hazardous if it occurred outside. The U.S. does not regulate indoor air pollution. Other gas appliances, like water and air heaters, are required to vent outside.

"Since then, even more research has shown that gas stoves pose risks to indoor air quality and public health — particularly in low-income communities and communities of color, where they're more commonly found in housing," Ellison wrote.

Ellison signed a letter to the CPSC along with others including the attorneys general of the District of Columbia, Delaware, Maryland, Massachusetts, New York, Rhode Island, Oregon, Vermont and Washington.

The American Gas Association, an industry group, argued in a statement that scientific research "does not provide sufficient or consistent evidence demonstrating that there are chronic hazards from gas ranges," and cited a review of studies the association funded.

Burning methane on a cook stove, the planet-warming compound that makes up natural gas, has been shown to create nitrogen dioxide, or NO2, in several studies including one 2022 paper in Environmental Science and Technology. A 2020 report by several nonprofit environmental groups, including the Rocky Mountain Institute, found the same — and that using the oven of a gas appliance also emitted the pollutant.

"We've known for a very long time about the impact of NO2 on respiratory health, especially with outdoor pollution we've had data on for decades," said Dr. Laalitha Surapaneni, an assistant professor at the University of Minnesota and a clinician at M Health Fairview.

The compound is linked to the development of asthma — but recent research has highlighted this effect from stoves in particular. A 2022 study published in the journal Environmental Research and Public Health found that almost 13% of childhood asthma cases across the country could be attributed to gas stoves used at home.

Part of the problem is that many homes don't adequately vent the cooktops.

"Studies have found in smaller homes when there's poor ventilation, when you start cooking, within minutes the levels [of pollutants] can get very high," Surapaneni said.

Ventilation is one of the major concerns outlined in the letter Ellison joined — he and the other signers asked CPSC to consider new standards for stoves to ensure anything they emit would be flushed out of a home.

In its statement, the American Gas Association said it has been working already with the CPSC on safety guidelines, and that it was at the "forefront of the development of safety standards and installation codes."

While the agency mulls how to regulate the products across the country, some states are stepping in to limit natural gas, which is also a potent greenhouse gas. New York State recently moved to ban natural gas hookups in most new buildings, Reuters reported.

In Illinois, there was also an effort this year to mandate warning labels on new gas stoves, pushed by the state's Public Interest Research Group, a nonprofit that works in consumer protection. The bill made it out of an Illinois House committee, but did not pass out of the chamber.

Abe Scarr, the director of Illinois PIRG, said he originally saw the proposal as a way to start a discussion about the health effects of cooking with gas, but he was eventually convinced that warning labels would be effective on their own. A study by PIRG and the Sierra Club showed that sales associates in big-box stores were mostly unaware of the potential health impacts of burning methane.

"The vast majority of the time, we got incomplete or bad information," he said. "That's one reason to think, 'Oh, this would actually be useful.' "