New Study Finds Natural Gas Leaking From Interstate Pipelines Contains Hazardous Air Pollutants and Carcinogens

Newswise — Natural gas transported through interstate pipelines contains hazardous air pollutants and known human carcinogens, says first of its kind study published in Environmental Research Letters by researchers at the nonprofit PSE Healthy Energy Research Institute.

In the United States, interstate transmission pipelines that transport natural gas release significant amounts of unburned gas during routine operations and unintentional leaks (eg, purges and blowouts). In 2020 alone, the Environmental Protection Agency estimated that natural gas transmission infrastructure leaked more than 1.4 million tonnes of methane, a potent greenhouse gas. Despite this, no previous analysis has assessed whether the gas in this system contains any hazardous air pollutants.

“Interstate gas pipelines are critical energy infrastructure that is normally off-limits to researchers,” said study lead author Curtis Nordgaard, an environmental health scientist at PSE Healthy Energy and board-certified pediatrician. “This is the first study to examine the chemicals circulating in our nation’s vast natural gas transmission system. Our results indicate that there are startling levels of harmful and carcinogenic air pollutants, creating potential health risks if gas leaks into nearby communities.

Using industry-reported data from infrastructure applications submitted to federal regulators, PSE scientists calculated the concentration of hazardous air pollutants in natural gas transmission pipelines. The researchers found BTEX (benzene, toluene, ethylbenzene, and xylenes) and hexane reported in nearly every document containing data on hazardous air pollutants. Industry reports also included other health-damaging compounds, including mercury, radioactive radon gas, and hydrogen sulfide. While the concentrations of these chemicals varied, some were important to health. In the case of benzene, concentrations have been reported up to 299 parts per million, or 30,000 times the short-term exposure level considered low risk by the California Environmental Protection Agency. Many of the reported chemicals are known to cause neurodevelopmental disorders, lung cancer, leukemia and respiratory disease.

“We know that natural gas transmission infrastructure is responsible for climate-damaging methane emissions. This new study indicates that these leaks may also contain chemicals that are hazardous to human health,” said Seth BC Shonkoff, Executive Director of PSE Healthy Energy. “Stopping natural gas leaks is essential for the climate and for protecting the health of our communities. »

The researchers used industry-reported data from natural gas infrastructure expansion applications approved by the Federal Energy Regulatory Commission (FERC) between 2017 and 2020 and ongoing industry metrics reported for five interstate pipelines. from December 2020 to June 2021. Because the industry is not strictly required to report the presence of hazardous air pollutants in expansion applications, more than 50% of applications reported no hazardous pollutant data. The pipelines assessed represent 45% of all onshore natural gas transmission systems by kilometer.


About PSE Healthy Energy

PSE Healthy Energy is a not-for-profit research institute dedicated to providing evidence-based scientific and technical information on the public health, environmental and climate dimensions of energy production and use . We are the only interdisciplinary collaboration focused specifically on health and sustainability at the intersection of energy science and policy. Visit us at and follow us on Twitter @PhySciEng.

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