The new report builds on earlier studies from the same research group. In one study, researchers also detected benzene and other hazardous air pollutants in samples of unburned gas collected from residences in the Boston metropolitan area. In another study conducted in California, Dr. Lebel found that gas stoves leaked significant amounts of methane even when the stoves were turned off.
For the latest study, researchers combined the leakage findings with new measurements of benzene in unburned gas to model potential indoor benzene concentration levels. They found that in some of the worst cases, the concentration coming from the gas hookup was similar to that found in homes with smokers.
There are some factors that influence indoor benzene levels, like the quality of ventilation or the size of the kitchen. But this study found benzene in unburned gas, which suggests that “simply opening the windows or turning on a range hood while the stove is on” will not eliminate the risk, said Kelsey Bilsback, a senior scientist at PSE Healthy Energy.
Increasingly, environmentalists and local officials in states like California and Massachusetts have pushed to phase out gas appliances in favor of electric ones, mostly citing the emissions impact of burning fossil fuels like natural gas. Homes and buildings are directly responsible for about 13 percent of the country’s greenhouse gas emissions, mostly from gas burned in stoves, ovens, hot water heaters and furnaces.
Methane, the main component of natural gas, is a particularly potent greenhouse gas. If released into the atmosphere unburned, it can warm the planet more than 80 times as much as the same amount of carbon dioxide over a 20-year period.
The new research indicates that “health and climate go hand in hand,” said Drew Michanowicz, a senior scientist at PSE Healthy Energy. While it may not be feasible or affordable for some homeowners to make the switch immediately, energy policies that provide tax credits and rebates for electric appliances are a step in the right direction, he said.
Outside of smoking, “most of the major sources of benzene in our lives are associated with fossil fuels,” said Rob Jackson, an earth scientist at Stanford University who did not work on the study. Those sources include motor vehicle exhaust, gasoline, and products made with petrochemicals, like plastics, rubbers and detergents.