In Europe, gas cookers and ovens can slowly leak dangerous chemicals, posing health risks to inhabitants. Almost 10% of homes inspected across the UK, Netherlands, and Italy had leaks exceeding exposure limits for the carcinogenic chemical benzene.

“Living with a gas burner is akin to living with a smoker,” asserts Drew Michanowitz from PSE Health Energy in Oakland, California. “Sidestream smoke produces similar benzene levels indoors.”

Naturally, methane and natural gas can harbor several volatile organic compounds (VOCs), some of which are known to be harmful, such as benzene, toluene, ethylbenzene, xylene, and hexane. Benzene is particularly concerning due to its links to serious health issues, including cancer (especially leukemia), immune suppression, anemia, and excessive bleeding.

Previous research has identified high benzene concentrations in natural gas sourced from the North Sea and the Netherlands. However, the extent of human exposure remained unclear until Mihanovic’s team collected gas samples from 72 homes across the UK, Netherlands, and Italy.

When compared to levels found in the United States, benzene concentrations were alarmingly higher—nine times greater in Italy, 37 times higher in the UK, and an astonishing 66 times higher in the Netherlands.

The research team sealed kitchens in 35 homes to monitor for gas leaks, estimating that 9% of these homes could exceed safety limits set by the UK and the European Union. No level of benzene exposure can be considered safe.

“These levels are just from gas leaks,” said Mihanovic. “Other sources of benzene could elevate actual concentrations even further.”

“Natural gas leaks could represent a significant source of benzene contamination based on existing sources and household ventilation rates,” commented Nicola Carslaw from the University of York, UK, who was not part of the study. “Individual household behaviors also play a huge role.”

Mihanovic believes the surveyed homes accurately reflect a broad population. Interestingly, stove leak rates in Europe were lower on average than those previously recorded in the US. This may indicate either fewer leaks in Europe or that uninspected homes may present a higher leak rate.

For Paul Monks, a researcher at the University of Leicester in the UK, the solution is clear. “An increasing body of evidence regarding indoor air pollution linked to gas stoves underscores the need to transition away from them for improved health and environmental benefits,” Monks says.

Induction stoves offer numerous advantages, being energy efficient, non-polluting, low fire risk, and eliminating the chance of larger explosions. However, some individuals remain attached to gas cooking, according to Mihanovic.

Cooking with gas can also release pollutants like benzene and nitrogen oxides, with leaks presenting a larger hazard, as cooking durations are generally short with extractor fans often in use.

Most detected leaks fell below levels that would typically trigger a smell. Mihanovic suggests increasing gas odorants to detect more of these slow leaks, but notes that “our sense of smell is imperfect, varying greatly from person to person.”

While adequate ventilation can improve indoor air quality when outdoor air is clean, initiatives aimed at boosting energy efficiency often compromise ventilation rates. “We have a long road ahead in evolving building codes to address energy efficiency alongside ventilation and indoor pollution sources,” he stated. For example, implementing heat recovery ventilation systems could enhance airflow while minimizing energy loss.