Natural gas delivered to homes contains some chemicals linked to cancer in low concentrations, a new study finds. The researchers also found inconsistent levels of odorants – the substances that give natural gas its characteristic “rotten egg” smell – that can increase the risk of minor leaks going undetected.
The study, published in the journal Environmental Science & Technology, adds to the growing body of research linking the supply and use of natural gas with adverse public health consequences. copper and climate.
Most previous studies have documented pollutants present at the site of oil and gas extraction, but there are “fewer studies as you work your way up the supply chain,” says Drew Michanowicz , the study’s lead author, said “where we actually use it, in our homes. “
Over 16 months, researchers led by the Harvard TH Chan School of Public Health collected 234 samples of unburnt natural gas from 69 homes in the Boston metropolitan area that received natural gas from three suppliers. grant. They found 21 “air toxins” – an Environmental Protection Agency classification of dangerous pollutants known or suspected to cause cancer, birth defects or adverse environmental effects – including benzene, detected in 95% of samples.
According to the Centers for Disease Control and Prevention, short-term exposure to high levels of benzene can especially lead to drowsiness, dizziness, headaches, and eye and skin irritation. Long-term exposure can increase the risk of blood disorders and certain cancers such as leukemia.
This highly flammable chemical is colorless or pale yellow and is found in coal and oil products, including plastics, plastics and nylon fibers, as well as some rubbers, dyes and pesticides. It is also frequently found in car exhaust, cigarette smoke, and gasoline.
Dr Michanowicz said Friday during a conference call with reporters that the concentration of benzene the researchers found in the natural gas samples was “much lower than that of gasoline”. Even so, he said, the finding is interesting because “natural gas is used so widely in our society and in the spaces of our homes.”
According to the EPA, Americans spend more than 90% of their time indoors, where concentrations of some pollutants can be two to five times higher than outdoor concentrations.
Benzene is a carcinogen and exposure increases over time, leading some experts to suggest that there is no safe level of exposure.
The goal of their study was to determine the presence and concentrations of certain hazards, the researchers said, and 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, an earth scientist at Stanford University who did not work on the study. “On the other hand, any unnecessary benzene in your home is too much.”
Unburnt natural gas also contains high levels of odorants or substances that produce unpleasant odors, the researchers said. Methane, the main component of natural gas, has no odor, so odorants are often added to help detect leaks.
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“If there are fewer odorants in the natural gas stream, there’s a higher chance of larger leaks that persist without the smell to them,” Dr Michanowicz said on Friday’s call.
When released into the atmosphere without being burned, methane is a particularly potent greenhouse gas. It could warm the planet 80 times more than the same amount of carbon dioxide over a 20-year period. In recent years, oil and gas companies have come under fire for often emitting large-scale, invisible methane.
Across the country, an increasing number of cities are trying to phase out natural gas connections to homes and businesses in favor of electricity alternatives, largely due to the emissions impact of continued burning of fossil fuels.
According to Curtis Nordgaard, a pediatrician and study co-author, the new study shows that natural gas leaks not only release methane, but also create airborne toxins that can be harmful to health community health. “We might want to rethink those leaks as not just a climate issue, but a health issue,” he said.
Dr. Nordgaard is a senior scientist at PSE Healthy Energy, a nonprofit research institute focused on public health and the climate impact of energy production, as is Dr. Michanowicz.
With this study, the researchers say they hope to fill gaps in the availability and transparency of gas composition data. Pipeline operators and gas suppliers in the United States often test the composition of the gas, in line with the recommendations of the North American Energy Standards Council, an industry organization that sets standards standards for electricity and natural gas markets.
However, gas composition tests typically measure only the 16 most abundant components of natural gas. That list does not include some of the ingredients the researchers identified, like benzene.