Gas stoves can produce more benzene than passive smoking

Cooking on a gas stove could produce higher amounts of a cancer-causing chemical than passive smoking, a new study suggests.

Researchers from Stanford University and PSE Healthy Energy, a nonprofit research institute, tested gas and propane stoves in 87 homes in California and Colorado. The study is believed to be the first to quantify the levels of indoor benzene produced by gas-fired stoves.

The scientists found that the devices emitted “detectable and repeatable levels of benzene,” a known carcinogen, which increased indoor concentration levels above health benchmarks in some homes.

The new findings, published June 15 in the journal Environmental Science & Technologycome amid a culture war in the US over the device, which multiple studies have suggested could be linked to negative health outcomes, sparking speculation that new gas stoves could be banned in the country.

Gas stoves can increase indoor benzene levels

Through their research, the scientists concluded that a gas or propane burner on high or an oven set to 350 F for 45 minutes increased kitchen benzene concentrations above baseline levels in every kitchen tested. In nearly a third of those cases, indoor benzene concentrations exceeded levels attributed to secondary tobacco smoke.

Benzene, which is produced by both human activities and natural processes, has been linked to cancers such as leukemia. According to the World Health Organization and the European Commission, indoor benzene levels should be “minimized as much as possible”.

“Benzene is a carcinogen and that worries us,” points out Jeffrey Siegel, a professor of civil engineering at the University of Toronto, whose research focuses on indoor air quality and ventilation. Siegel, who is not involved in the study, added that no amount of benzene is good for health.

Indoor air quality is also a matter of equity

The scientists also found that the air pollutant can spread from the kitchen and into the bedrooms. Researchers measured benzene concentrations in the bedrooms of six homes with open kitchens after turning the oven on at 475 F for an hour and a half.

With interior doors open, but without using fans to mix the air, bedroom benzene levels peaked at five to 70 times above baseline levels, the researchers found.

The scientists suggested that low-income families, particularly those living in smaller homes where bedrooms are closer to the kitchen, are at greater risk of exposure to elevated benzene levels.

“Indoor air is essentially an equity issue, and we’ve seen that with COVID,” said Siegel, who also holds joint appointments at the University of Toronto’s Dalla Lana School of Public Health and the Department of Physical & Environmental Sciences. “I do a lot of research on social housing in Toronto, where we see much higher concentrations of almost everything in social housing compared to single-family housing.”

Installing an extractor hood can have more of an impact than removing a gas stove

The new study comes amid more research on gas-powered stoves, as other research has suggested the popular device may be linked to negative health outcomes, including childhood asthma.

While removing a gas stove would reduce the amount of contaminants released from the stovetop, installing a high-quality range hood could have a greater overall impact on indoor air quality, Siegel said.

“The right thing to do when cooking, however you cook, is to have a good range and use it,” he said, pointing out that if installing an extractor hood isn’t possible, opening a window can help reduce air pollution, albeit less effectively.

Siegel explained that even if you replace a gas stove with a different type of cooktop, the cooking itself still produces harmful pollutants, depending on the foods you cook, the types of oil you use, and the heat at which you cook the food.

“If you ventilate the cooking space, you remove the pollution at the source,” says Siegel, however it originates. “In my ideal world, every house in Toronto would have an extractor hood — a good, quiet (one) that actually works.”

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