First Study of Its Kind Detects 44 Hazardous Air Pollutants at Gas
By Lisa Song, InsideClimate News 
Dec 3, 2012
With gas wells in some states being drilled near schools and homes,
scientists see a need for better chemical disclosure laws and
By Lisa Song
For years, the controversy over natural gas drilling has focused on
the water and air quality problems linked to hydraulic fracturing, the
process where chemicals are blasted deep underground to release
tightly bound natural gas deposits.
But a new study  reports that a set of chemicals called non-methane
hydrocarbons, or NMHCs, is found in the air near drilling sites even
when fracking isn't in progress.
According to a peer-reviewed study in the journal Human and Ecological
Risk Assessment , more than 50 NMHCs were found near gas wells in
rural Colorado, including 35 that affect the brain and nervous system.
Some were detected at levels high enough to potentially harm children
who are exposed to them before birth.
The authors say the source of the chemicals is likely a mix of the raw
gas that is vented from the wells and emissions from industrial
equipment used during the gas production process.
The paper cites two other recent studies on NMHCs near gas drilling
sites in Colorado. But the new study was conducted over a longer
period of time and tested for more chemicals than those studies did.
"To our knowledge, no study of this kind has been published to date,"
the authors wrote.
The researchers took weekly air samples at a site that's within one
mile of 130 gas wells in Garfield County, Colo., with little other
industry aside from natural gas production. They detected more than 50
chemicals between July 2010 and October 2011, including 44 with
reported health effects. The highest concentrations were measured
after new wells were drilled, but the concentrations did not increase
after the wells were fracked.
Carol Kwiatkowski, one of the study's authors, said that because of
limitations on funding and access to drilling sites, the study doesn't
definitively link the gas fields to the air pollutants. But because
the research was conducted in a region with few people and roads,
"natural gas drilling would be the first thing anyone would look at."
What the study shows, she said, is that more research is needed on all
stages of gas production. "It's not all about fracking. ... Air
pollution needs more focus and scrutiny."
Kwiatkowski is executive director of the Endocrine Disruption Exchange
 (TEDX), a nonprofit research organization in Colorado that studies
the impact of environmental pollutants on the endocrine system, a
network of hormone-producing glands that affects nearly every organ in
the body. TEDX has spent years studying the health effects of natural
gas drilling, and its reports are routinely criticized by the
Kathleen Sgamma, vice president of government and public affairs at
Western Energy Alliance , which represents oil and gas drillers in
the American West, said the TEDX scientists have produced "a study
that clearly doesn't come up with the results they're trying to show."
Sgamma questioned the scientists' qualifications, as well as the
quality of the journal that published their findings. "This was
clearly not a well-thought out and well peer-reviewed study," she
But Robert Jackson , a professor of energy and environmental
studies at Duke University who was not involved in the research, said
the study is valuable because it shows that more study is needed about
how drilling affects communities near gas fields.
"There's the question of whether there are long-term health effects,"
he said. "It warrants a follow-up [health] study."
Many residents of the sparsely populated area live within a mile of
active wells. As gas drilling expands throughout the nation,
production is moving closer to populated areas, with wells in some
states now being drilled within a few hundred feet of schools and
All of the chemicals TEDX detected were at levels well below the
limits the federal government recommends to protect workers from
dangerous chemicals. However, those standards are usually designed for
healthy adult males who are exposed to the chemicals on and off for 40
hours a week. Scientists say the risks would likely be different for
people—including pregnant women, children and the elderly—who live
near gas fields and are exposed 24 hours a day, seven days a week.
"We've been overlooking these non-methane hydrocarbons until now,"
said Theo Colborn, president of TEDX and the paper's lead author.
"They've been measured before in cities ... otherwise, no one has
looked at [them] as related to natural gas drilling in rural areas."
What the Scientists Found
Non-methane hydrocarbons are emitted by industrial equipment and also
by unprocessed natural gas.
When an operator drills a new well, most of the raw gas that flows out
of the ground is methane—the target compound that's collected and
sold. The gas also contains water and dozens of NMHCs, including the
carcinogen benzene. On average, NMHCs account for 18 percent of the
unprocessed gas and are released into the air at various stages of
John Starck, an engineer and president of EGL Resources , a Texas
oil and gas company, said very little raw gas escapes during the
initial drilling phase, because the gas-bearing rock is so
impermeable. Once the well has been fracked, the quantities of NMHCs
released would be on the order of parts per thousand or parts per
million, unless there is a leak, he said.
The NMHCs in the study were detected at levels of parts per million,
parts per billion and parts per trillion, but the endocrine system is
so sensitive that even tiny doses  can lead to large health
effects. Federal safety standards rarely consider the impacts of low
dosage testing, an omission that scientists say should be addressed.
The study's authors detected thirty NMHCs that affect the endocrine
system. Several belong to a class of compounds called polycyclic
aromatic hydrocarbons (PAHs) and were detected at levels that other
scientists have found are high enough to impact child development. In
those studies, clinical researchers gave pregnant women living in
cities personal air monitors, then tracked their children's
development. Women exposed to a certain level of PAHs were more likely
to have children with lower birth weight and lower IQ scores.
One chemical found at surprisingly high levels was methylene chloride,
a common laboratory solvent. It's not a component of raw gas and
doesn't appear on any of the public disclosure forms of chemicals used
during drilling and fracking. "However, residents and gas field
workers have reported that methylene chloride is stored on well pads
for cleaning purposes," the authors wrote.
Robert Howarth , a Cornell University scientist who wasn't
involved in the study, said the presence of methylene chloride points
to a need for better chemical disclosure laws. "Methylene chloride is
a surprise…We need a lot more information on what's used at drilling
While drilling companies are required to disclose many of the
chemicals used for fracking, they are usually allowed to keep
proprietary chemicals secret. Drilling and cleaning compounds are
rarely, if ever, subject to public disclosure.
Sgamma, the industry representative, said she was not aware of
methylene chloride being used on well pads. She said the samples were
probably contaminated in the lab.
Kwiatkowski said TEDX considered that possibility and ran blank
samples to test for contamination. They didn't find methylene chloride
in the blanks, but found it "over and over again" in the collected air
The TEDX study was inspired by years of complaints about headaches and
respiratory problems the researchers had heard from people living near
gas wells. Many of the symptoms began the moment drilling started,
long before the wells were fracked, Kwiatkowski said.
That prompted the scientists to study air quality before and after
drilling. They identified a well pad slated for drilling and set up an
air sampling station near a home 0.7 miles from the well pad. There
were 130 active gas wells within one mile of the site.
Kwiatkowski said the ideal sampling station would have been located
directly on the well pad, but TEDX has had little success persuading
the industry to cooperate with its research, so the researchers didn't
ask for access to the well pad. They also didn't want to draw unwanted
attention to their work. Local residents are divided when it comes to
the benefits and risks of gas drilling, and Kwiatkowski said they
didn't want to cause trouble among neighbors. Their choice of location
was further constrained by the need for a constant source of
electricity and the need to protect the station from possible
The scientists took a partial set of baseline data on July 2010,
before any wells had been drilled on the pad. On October 19, after
residents called to report activity on the well pad, the scientists
rushed in to take a full set of baseline readings. The first well was
drilled three days later.
Air sampling continued weekly until October 2011. All samples were
analyzed in EPA-certified labs. The scientists tested for more than
100 chemicals and found over 50 at levels high enough to be detected
by their instruments.
When the dates of the drilling and fracking activity were posted
online, in accordance with Colorado's disclosure laws, the scientists
learned that the company had drilled 16 wells on the well pad between
October 2010 and March 2011. Two other well pads were drilled starting
in April and July. Fracking followed the drilling. About 100 other
wells within a mile already were producing gas and were neither
fracked nor drilled during the study period.
The data showed a major spike in chemical concentrations after the
first 16 wells were drilled, but not after fracking. The increase was
significant when compared with the baseline samples collected before
the drilling, as well as samples from most of the year after drilling
Colborn said that suggests the increased emissions are linked to the
raw gas released from drilling—but she said there's no way to tell for
sure, because they couldn't directly sample emissions from the well
pad. Colborn said TEDX and other scientists are already making plans
for a follow-up study to chemically fingerprint the source of the
Jackson, the Duke University scientist, said the paper hasn't
convinced him that the increased emissions are directly tied to the
well pad it studied instead of the combined effect of the region's
natural gas operations.
He said the evidence is weak because the spikes occurred only during
the middle two months of the five-month drilling period, and because
the emissions could have originated from the 130 other wells in the
There's no question the study "is documenting air quality in that
valley," he said, "and that's still valuable," especially when it
comes to health implications for local residents.
Industry Questions Study's Credibility
Sgamma, the industry representative, said the TEDX study "has all the
problems you'd expect when a zoologist and psychologist attempt to
conduct an air quality study."
The "zoologist" refers to Colborn , who helped pioneer the field
of endocrine disruption in the 1980s and served on numerous government
science panels. Colborn describes herself as an "environmental health
analyst"—a term that reflects her multidisciplinary background in
zoology, epidemiology, toxicology, freshwater ecology and water
Kwiatkowski  has a Ph.D. in experimental psychology and
specializes in statistical analysis. She is a former assistant
professor at the University of Colorado School of Medicine.
According to the TEDX website , the organization runs on three
basic principles: rigorous scientific analysis, promoting education on
endocrine disruption and advocating policy to protect public health
and the environment. Kwiatkowski said she wasn't surprised by Sgamma's
criticism, because TEDX has been willing to tackle issues that other
scientists "might typically not want to go out on a limb for."
"What industry does is attack your reputation as a scientist,"
Kwiatkowski said. "Young scientists in particular can't afford to have
their reputations challenged."
The TEDX study cites two recent studies with similar research goals—a
Health Impact Assessment  (HIA) from the University of Colorado
School of Public Health and a pilot study led by the National Oceanic
and Atmospheric Administration.
The HIA was commissioned in 2010 to examine the potential health
affects of a pending gas drilling project in Garfield County, the same
county Colborn's group examined, but the county commissioners cut its
funding  before it could be completed. A draft of the HIA from
Feb. 2011  cited a 2007 air monitoring report that identified oil
and natural gas production as the largest contributor of benzene in
The NOAA study , published in February by the Journal of
Geophysical Research, found that oil and gas operations released more
methane and benzene than previously thought. It used a chemical
fingerprint to pinpoint drilling operations as the source of the
contaminants, but it examined far fewer non-methane hydrocarbons than
the TEDX paper.
Researchers from the Health Impact Assessment and a co-author of the
NOAA study declined to comment on the TEDX paper. The lead author of
the NOAA paper did not return requests for information.
Sgamma also questioned the researchers' decision to publish the paper
in Human and Ecological Risk Assessment, which she said is not a
"typical" destination for air quality studies.
Kwiatkowski said they chose the journal because they wanted it to
reach scientists who study risk assessment.
Barry L. Johnson , the journal's editor-in-chief for the past 12
years, said the publication's first priority is the quality of the
science in the manuscripts it receives. He said it has published
papers written by industry researchers and that industry scientists
serve on the journal's board. Johnson has worked for the EPA and the
federal Agency for Toxic Substances and Disease Registry, and is an
adjunct professor of public health and environmental policy at Emory
The TEDX paper was processed like any other study, Johnson said. It
was sent to two scientists for peer review, both of whom have
published widely on issues of air quality. The reviewers' names are
kept private, he said, because his journal operates under a
double-blind review system, where authors and peer reviewers are
unaware of each others' identities in order to avoid potential
conflicts of interest.
Johnson said his publication "deemed the [TEDX] paper, as we have
deemed others dealing with air quality, as being relevant to the aim,
purpose and scope of our journal." He said that Sgamma is welcome to
submit formal comments on the paper.
The TEDX study is "clearly labeled and presented as an exploratory
study," he said. "It has strengths and limitations—I don't know of any
studies that don't. That's just how science works ... and this may
contribute towards a better understanding of what's happening around
Only when the last tree is cut, only when the last river is polluted, only
when the last fish is caught, only then will they realize that you cannot
eat money. – Cree proverb