In the US, 38% of homes depend on gas stoves. The gas-fired appliance has a devoted following, with chefs and serious cooks long testifying to its perceived superiority over electric stoves.

But the safety of gas stoves is being questioned. The device emits pollutants that are harmful to human health and the environment. The more scientists understand these pollutants, the more concerning gas stoves become.

“You would never stand over the exhaust of a car and just breathe in the exhaust fumes, and yet that’s the same thing we do every day (with gas heaters),” says Rob Jackson, professor of earth system sciences at Stanford University.

The combustion of natural gas or propane, which provides the gas stove with its heat, produces a variety of pollutants, including nitrogen dioxide, carbon monoxide, formaldehyde and benzene, among others. Not only do gas stoves emit these chemicals when they are on, but research has shown that they also leak pollutants when they are off.

A health risk

Nitrogen dioxide is a particularly harmful substance emitted from gas stoves, but its effects have only come to light in the past decade. The gas irritates the respiratory tract and worsens lung diseases such as asthma. A World Health Organization analysis reported that children in households with gas stoves had a 13% increased risk of asthma, while other analyzes found the risk was as high as 42%.

Based on a better understanding of the health effects of nitrogen dioxide, the WHO has reduced recommended exposure by 75% in 2021. And both the American Public Health Association and the American Medical Association have stated that gas stoves increase air pollution and are linked to asthma in children.

Benzene, another substance emitted from gas stoves, is a known carcinogen also found in second-hand smoke. A 2022 study found that gas stoves emit benzene even when not in use. While there is no data measuring cancer rates among people with gas stoves, the WHO stated in 2019 that there were no safe levels of benzene exposure.

Carbon monoxide also poses a risk to gas stove users. Carbon monoxide poisoning is the better known risk, but usually only occurs when a gas stove malfunctions. Low levels of carbon monoxide emitted by a properly functioning gas stove can also have health consequences. The EPA reported that homes with a properly functioning gas stove have 3 to 10 times more carbon monoxide in the air. And in houses where the stove is poorly ventilated, this can be much more.

There is research showing that these low doses of carbon monoxide – levels that are elevated but not enough to trigger a carbon monoxide alarm or cause carbon monoxide poisoning – can worsen cardiovascular disease in vulnerable populations.

Environmental consequences

However, gas stoves pose not only a risk to human health. “Methane is leaking from gas heaters into people’s homes even when (the heater) is off,” said Eric Lebel, Ph.D., senior scientist at PSE Health Energy, a science nonprofit specializing in energy policy, citing his research from 2022 to measuring methane leakage from gas stoves. Methane “is a strong greenhouse gas, more than 80 times stronger than carbon dioxide,” he said.

“Because methane is so strong, those small leaks matter,” says Lebel. “And it’s not just about the gas appliance, but about the transport of that gas to your home. That is also part of the climate impact of burning that gas in your home.”

Gas stoves have higher emissions than electric stoves, especially when you take leaks into account, Jackson said. In some states where the electricity grid runs on coal, an electric stove will not be much more environmentally friendly. But as energy gets cleaner — and in states where they already prioritize clean energy — electric heaters will become much better for the environment, he said.

How to reduce your risks

Although the health and environmental risks of a gas stove are serious, gas stove users have options to lower their risk. Which one suits you best depends on your budget.

“If you’re lucky enough to have the money,” Jackson said, replacing your gas stove is the best option, even if the stove isn’t at the end of its life. The problem is that it is an expensive transition. But research shows that it can have a major impact.

Between 2015 and 2021, a national program in Ecuador helped replace gas stoves with induction stoves in 10% of Ecuadorian households. In a 2023 analysis, researchers reported that the large-scale exchange increased electricity use by 5% but reduced greenhouse gases because the national grid is 80% hydroelectric. Interestingly, the researchers also found that the total number of hospital admissions and respiratory-related hospitalizations decreased as the number of induction cooktops increased.

If replacing your heater is not an option, make sure your heater is properly ventilated. “Every time your oven is on, your ventilation is on, even if you’re just boiling water,” Lebel said.

Although a hood vent won’t eliminate contaminants, an exterior vent can remove 30% to 50% of contaminants, Jackson said. However, many cheaper vents are not actually connected to the outside air. These vents recirculate or dilute pollutants. That may be safer for the person cooking immediately, but those contaminants are pushed throughout the house, Jackson said.

Switching to outdoor ventilation is ideal, but also expensive. If you don’t have the money for this renovation, you can start by improving ventilation by simply opening a window while you cook, Lebel said. This sends some of the pollutants recirculated through the vents outside. You can also reduce the pollutants in your gas stove using an air purifier. Make sure you choose one that absorbs particulate matter. And finally, prioritize other cooking methods, such as microwaves, air fryers, electric kettles and induction cooktops, to reduce indoor pollution.

Gas stoves pose real health and environmental risks. But the good news is that “there are things that can be done to reduce health exposure and climate impacts,” Lebel said.