2020

Natural gas flaring poses pregnancy risks


Researchers from UCLA FSPH and USC found exposure was associated with a 50% higher risk for preterm birth compared with no exposure.

gas flare

Researchers from the UCLA Fielding School  of Public Health and the University of Southern California have found that a high level of exposure to oil and gas “flaring” events — the burning off of excess natural gas at production sites — is associated with a 50% higher risk for preterm birth, compared with women who are not exposed to flaring.

The researchers defined a high level of exposure as 10 or more nightly flare events within a distance of 5 kilometers (about 3 miles) of the woman’s home.

“Prior studies suggest living near oil and gas wells adversely affects birth outcomes, but no studies had yet examined flaring — the open combustion of natural gas,” said Lara Cushing, an environmental health scientist at the Fielding School and the study’s co-lead author. “Our findings suggest that living within three miles of flaring adversely impacts pregnant women and infants.”

The study is published today in the journal Environmental Health Perspectives. Researchers examined 23,487 live single births to women living within Texas’ Eagle Ford Shale between 2012 and 2015. The Eagle Ford Shale, measuring 50 miles wide and 400 miles long, is one of the nation’s most productive oil and gas regions, due to unconventional drilling practices that include hydraulic fracturing, commonly referred to as fracking. In a previous study, the research team estimated the area was subject to more than 43,000 flaring events between 2012 and 2016.

Of those births, 10.6% were preterm, meaning that they occurred before the end of the 37th week of pregnancy. Preterm birth is associated with complications such as immature lungs, difficulty regulating body temperature, poor feeding and slow weight gain. Of the births in the high flare exposure group analyzed by researchers, 14% were preterm.

“The fact that much of the region is low income, and that approximately 50% of residents living within three miles of an oil or gas well are people of color, raises environmental justice concerns about the oil and gas boom in south Texas,” said Jill Johnston, an environmental health scientist at the USC Keck School of Medicine, who co-led the study. “Measures to minimize flaring — such as more stringent regulation of flaring or investments in renewable energy and energy efficiency measures that reduce reliance on fossil fuels overall — would protect the health of infants.”

Flares have been shown to release a variety of chemicals, such as benzene, as well as fine particle pollution, carbon monoxide, nitrogen oxides, heavy metals and black carbon. Several of those combustion-related pollutants have been associated with a higher risk for preterm births and reduced birthweight in other contexts.

The researchers used satellite observations to measure flaring activity because systemic reporting of flaring is lacking. The team adjusted for other known risk factors for preterm birth, including age, smoking, insurance status and access to prenatal care.

Women who lived within 5 kilometers (about 3 miles) of a larger number of oil and gas wells also had a higher risk for a preterm birth than mothers who lived farther away. Their babies were also born weighing 19.4 grams (.7 ounces) lighter on average. That suggests that, in addition to flaring, other types of exposure to oil and gas wells may also be adversely affecting pregnancies, the researchers said.

Fifty-five percent of the women in the study identified as Latina or Hispanic, and the risk for preterm birth among Hispanic women exposed to high levels of flaring was greater than it was for non-Hispanic white women, who made up 37% of the study.

80% of flaring in the U.S. occurs in the Texas and North Dakota shale plays, where much of the nation’s unconventional oil production occurs. The practice remains largely underreported and unregulated, the researchers wrote.

The study’s other authors are Kate Vavra-Musser, Khang Chau and Meredith Franklin, all of USC. The research was supported by a grant from the National Institutes of Health/National Institute of Environmental Health Sciences.


The UCLA Fielding School of Public Health, founded in 1961, is dedicated to enhancing the public's health by conducting innovative research, training future leaders and health professionals from diverse backgrounds, translating research into policy and practice, and serving our local communities and the communities of the nation and the world. The school has 690 students from 25 nations engaged in carrying out the vision of building healthy futures in greater Los Angeles, California, the nation and the world.

Faculty Referenced by this Article

Dr. Lara Cushing
Lara Cushing
Environmental Health Sciences
Read Faculty Profile
Dr. Shane Que Hee
Shane Que Hee

Industrial Hygiene & Analytical Chemistry

Environmental Health Sciences
Read Faculty Profile
Brian Cole
Brian Cole
Environmental Health Sciences
Read Faculty Profile
Michael Jerrett
Michael Jerrett
Environmental Health Sciences
Read Faculty Profile
Faculty/staff profile placeholder image
Arthur Winer
Environmental Health Sciences
Read Faculty Profile
Feng Gao
Feng Gao
Environmental Health Sciences
Read Faculty Profile
Dr. Kevin Njabo
Kevin Njabo
Environmental Health Sciences
Read Faculty Profile
Dr. Wendie Robbins
Wendie Robbins
Environmental Health Sciences
Read Faculty Profile
Jian Li
Jian Li
Environmental Health Sciences Epidemiology
Read Faculty Profile
Dr. Oliver Hankinson
Oliver Hankinson

Dr. Hankinson is a Distinguished Professor of Pathology and Laboratory Medicine, and of EHS, and Chair of the Molecular Toxicology IDP

Environmental Health Sciences
Read Faculty Profile
Rachael Jones
Rachael Jones
Environmental Health Sciences
Read Faculty Profile
Faculty/staff profile placeholder image
Timothy Malloy
Environmental Health Sciences
Read Faculty Profile
Richard Ambrose
Richard Ambrose
Environmental Health Sciences
Read Faculty Profile
Mel Suffet
Irwin Suffet
Environmental Health Sciences
Read Faculty Profile
Dr. Yifang Zhu
Yifang Zhu
Environmental Health Sciences
Read Faculty Profile
Andre Nel
André Nel
Environmental Health Sciences
Read Faculty Profile
Miriam Marlier
Miriam Marlier
Environmental Health Sciences
Read Faculty Profile
Dr. Candace Tsai
Candace Tsai

Associate Professor for Industrial Hygiene and Environmental Health Sciences

Environmental Health Sciences
Read Faculty Profile
Pablo Cicero-Fernandez
Pablo Cicero-Fernandez
Environmental Health Sciences
Read Faculty Profile
Dr. Daniel Uslan
Daniel Uslan
Environmental Health Sciences
Read Faculty Profile
Jared Diamond
Jared Diamond
Environmental Health Sciences
Read Faculty Profile
Arabzadah, Hamid
Hamid Arabzadeh
Environmental Health Sciences
Read Faculty Profile
Faculty/staff profile placeholder image
Niklas Krause
Environmental Health Sciences Epidemiology
Read Faculty Profile
Rosenstock
Linda Rosenstock
Environmental Health Sciences Health Policy and Management
Read Faculty Profile
Tao Huai
Tao Huai
Environmental Health Sciences
Read Faculty Profile
Faculty/staff profile placeholder image
Kirsten Schwarz
Environmental Health Sciences
Read Faculty Profile
Arthur Cho
Arthur Cho
Environmental Health Sciences
Read Faculty Profile
Dr. Jane Valentine
Jane Valentine
Environmental Health Sciences
Read Faculty Profile
Michael Collins
Michael Collins
Environmental Health Sciences
Read Faculty Profile
Dr. Beate Ritz
Beate Ritz
Environmental Health Sciences Epidemiology
Read Faculty Profile
Angelo J Bellomo
Angelo Bellomo
Environmental Health Sciences
Read Faculty Profile
Faculty/staff profile placeholder image
Jesus Araujo
Environmental Health Sciences
Read Faculty Profile
Richard J. Jackson
Richard J. Jackson
Environmental Health Sciences
Read Faculty Profile
Curtis Eckhert
Curtis Eckhert
Environmental Health Sciences
Read Faculty Profile
Dr. Robert Schiestl
Robert Schiestl
Environmental Health Sciences
Read Faculty Profile
Faculty/staff profile placeholder image
Nicole Green
Environmental Health Sciences
Read Faculty Profile
Dr. Pouran D. Faghri
Pouran D. Faghri
Environmental Health Sciences
Read Faculty Profile

Related Content

pollution
April 3, 2019
Current methods may inadequately measure human health impacts from oil and natural gas extraction

Research from the UCLA FSPH, UC Berkeley & Cornell University conducted an examination of peer-reviewed studies published over 6 years on hazardous air pollutants associated with the extraction of oil & natural gas, & found that that measurements of hazardous air pollutant concentrations near operational sites have failed to capture levels above standard health benchmarks.

Read Full Article