TOXINS FOUND IN GAS PIPED TO HOMES IN CALIF.

Benzene among chemicals detected by researchers

The gas that is piped into millions of California homes contains hazardous air pollutants including benzene, a chemical linked to cancer, a new study found.

The researchers estimated that each year California gas appliances and infrastructure leak the same amount of benzene as is emitted by nearly 60,000 cars, but these leaks are unaccounted for in the state’s records.

The study, published Thursday in the journal Environmental Science & Technology, adds to a growing debate over proposals to limit the use of gas in homes because of its impact on climate change and public health. That issue has surfaced most notably in California, where in 2019 Berkeley became the first city to ban gas hookups in most new homes and buildings. Since then, dozens of cities in California and around the country have enacted similar ordinances.

Researchers have documented significant indoor air pollution and negative health impacts from using gas stoves. “Now we also know that even just having a gas appliance in your house can have health and climate impacts,” said Eric Lebel, the study’s lead author.

Several authors of the study, including Lebel, are senior scientists at PSE Healthy Energy, a nonprofit research institute focused on the public health and climate effects of energy production.

The study’s findings are not necessarily an immediate cause for concern for home cooks with gas ranges, but they can be an important consideration for homeowners who are preparing to replace appliances. Gas stoves are just one contributor to the indoor air pollution that many households live with every day. Smoking, some household cleaning products and fireplaces can all negatively impact indoor air quality.

In the study, researchers collected 185 samples of unburned natural gas from 159 homes across California served by three gas companies: Pacific Gas & Electric, SoCalGas and San Diego Gas & Electric. Each of the samples contained air pollutants categorized as hazardous by the Environmental Protection Agency, meaning they are known to cause cancer and other serious health impacts.

The most prevalent of those pollutants was benzene, a highly flammable chemical that can be colorless and odorless, which makes it hard to detect when it leaks. Long-term exposure to significant amounts of the chemical can increase the risk of blood disorders and certain cancers like leukemia.

While the detected levels of the chemical in most of the samples were low, benzene accumulates in the body over a person’s lifetime, and health risks increase almost linearly with exposure, said Dr. Philip J. Landrigan, a pediatrician and public health professor at Boston College who was not involved in the study. “There is really no safe threshold” for benzene exposure, he added.

The new report builds on earlier studies from the same research group.

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.