June 16, 2023 – Gas stoves emit the cancer-causing chemical benzene at levels higher than those found in secondhand tobacco smoke, according to a new study. Benzene, which is linked to an increased risk for leukemia and other cancers, can linger in homes at dangerous levels for hours, even with exhaust fans above stoves that vent outdoors.
The study, from Stanford University researchers, adds to the growing body of evidence that natural gas cooking stoves may pose health risks. Study results from evaluating benzene levels while gas and propane stoves were in use were published Thursday in the journal Environmental Science and Technology.
Researchers evaluated benzene levels in 87 homes in California and Colorado while the stoves had burners turned to high or when the oven was heated to 350 degrees Fahrenheit. They found that the levels of benzene emitted were 10 to 25 times higher than electric stoves, and they confirmed that none of the benzene emissions were coming from food being cooked. Benzene levels in this latest study were hundreds of times higher than levels previously determined to result from unburned gas leaking into homes.
“Benzene forms in flames and other high-temperature environments, such as the flares found in oil fields and refineries. We now know that benzene also forms in the flames of gas stoves in our homes,” said researcher Rob Jackson, PhD, a professor of Earth system science at the Stanford Doerr School of Sustainability, in a statement. “Good ventilation helps reduce pollutant concentrations, but we found that exhaust fans were often ineffective at eliminating benzene exposure.”
Researchers found that high levels of benzene could travel beyond the kitchen and stay inside long after cooking was finished.
“Benzene produced by gas and propane stoves also migrated throughout homes, in some cases elevating bedroom benzene concentrations above chronic health benchmarks for hours after the stove was turned off,” the authors wrote. “Combustion of gas and propane from stoves may be a substantial benzene exposure pathway and can reduce indoor air quality.”