Gas supplied to homes contains benzene and other hazardous chemicals, study finds

A new study has found that natural gas delivered to homes contains low concentrations of several cancer-causing chemicals. The researchers also found fluctuating levels of odorants — substances that give natural gas a characteristic ‘rotten egg’ smell — that can increase the risk of small leaks going undetected.

The study that was published in the journal Environmental Science & Technologyadds to the growing body of research that links the delivery and use of natural gas to detrimental effects on public health and the climate.

Most previous studies have documented the presence of contaminants where oil and gas production takes place, but “as you move up the supply chain, there is less research,” said Drew Mihanovich, lead author of the study, looking at “where we actually use it in our homes.”

Over 16 months, researchers collected 234 samples of unburned natural gas from 69 homes in the Boston metropolitan area that received natural gas from three suppliers. They found 21 “air toxic substances” — an EPA classification of hazardous pollutants known or suspected to cause cancer, birth defects, or adverse environmental effects — including benzene, which was found in 95 percent of the samples. .

According to the Centers for Disease Control and Prevention, short-term exposure to high levels of benzene in particular can lead to drowsiness, dizziness, headaches, and eye and skin irritation. Long-term exposure may increase the risk of blood disorders and certain types of cancer such as leukemia.

This flammable chemical is colorless to light yellow and is found in products made from coal and petroleum, including plastics, resins, and nylon fibers, as well as some types of rubbers, dyes, and pesticides. It is also regularly found in car exhaust, tobacco smoke and gasoline.

The concentration of benzene found by the researchers in the natural gas samples was “much lower compared to the amount in gasoline,” says the doctor. Mikhanovich said this on Friday during a conference call with reporters. Still, he says, the discovery is worrisome because “natural gas is so widely used in society and on our premises.”

According to the EPA, Americans spend more than 90 percent of their time indoors, where concentrations of some pollutants can be two to five times higher than outdoors.

Benzene is a carcinogen and exposure increases over time, leading some experts to suggest that there is no safe level of exposure.

The researchers said the purpose of their study was to determine the presence and concentration of certain hazards, and that more research is needed to understand the health risks.

“The biggest sources of benzene in most people’s lives are gasoline from cars and smoking,” said Rob Jackson, a geoscientist at Stanford University who was not involved in the study. “On the other hand, any unnecessary benzene in your home is too much.”

Unburned natural gas also contained fluctuating levels of odorants, or substances that give off a perceptible odor, the researchers said. Methane, the main component of natural gas, is odorless, so odorants are usually added to detect leaks.

“If there are fewer odorous substances in the natural gas stream, there is a higher chance of larger odorless leaks,” says Dr. Mikhanovich said in a Friday call.

When released into the unburned atmosphere, methane is a particularly potent greenhouse gas. He can warm the planet more than 80 times more the same amount of carbon dioxide over a 20-year period. Oil and gas companies have often been criticized in recent years for large-scale invisible methane emissions.

Through the whole country growing number of cities are trying to phase out natural gas connections to homes and businesses in favor of electric alternatives, mostly citing the impact on emissions from continued burning of fossil fuels.

A new study suggests that natural gas leaks cause the release of not only methane, but also toxic substances in the air that can harm public health, said Curtis Nordgaard, a pediatrician and co-author of the study. “We may want to rethink these leaks not just as a climate issue, but as a public health issue,” he said.

Dr. Nordgaard is a senior fellow at PSE Healthy Energy, a non-profit research institute specializing in the public health and climate impacts of energy production, as is Dr. Mihanovich.

The researchers said they hope to fill a gap in the availability and transparency of gas composition data with this study. Pipeline operators and gas suppliers in the United States routinely test gas composition in accordance with the recommendations of the Energy Standards Board of North America, the industry body that sets standards for the natural gas and electricity market.

However, gas composition tests typically only measure the 16 most common components of natural gas. This list does not include some components that the researchers have identified, such as benzene.