Case Series and Symptom Reports
Case Series and Symptom Reports
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| Case Series and Symptom Reports |
animal and human health effects potentially resulting from nearby natural gas drilling
operations. The summary of reported human health effects lacks specificity, but
mentions a variety of symptoms such as upper respiratory, burning eyes, headache,
gastrointestinal, dermatological, and neurological. The authors acknowledge the lack of
complete testing of water, air, soil, and animal tissues that hampered more thorough
analysis of the connection between gas drilling and health. They suggest further
investigation is needed, ideally with policy changes that could assist in the collection of
more complete data sets. Bamberger and Oswald were also guest editors for a 2013
special issue on shale gas development in the same journal (New Solutions). The
articles in that special issue largely expand on potential health concerns raised in the
original Bamberger and Oswald paper, although Bamberger and Oswald (2013) note in
their introduction to the special issue that firm conclusions about potential health
concerns cannot be established given the lack of relevant data.
Findings from an investigation done by the Earthworks’ Oil & Gas Accountability Project
were published in a non-peer-reviewed report (Steinzor, 2012). The report summarizes
the extent and types of health symptoms experienced by 108 people from 55
households from 14 Pennsylvania counties where HVHF is occurring. It also has results
of air sampling near 34 of the households and water sampling from nine of the
households. It is difficult to interpret the results of this assessment. Participants report
experiencing a number of symptoms, and the results suggest that those living closer
than ~½ mile from a gas drilling facility may report symptoms in larger proportions than
those living farther than ~½ mile. However, the sample is self-selected, and there was
no systematic assessment of baseline health status or comparison with a similar
population (the report does mention a five person control group that tended to
experience fewer symptoms) unaffected by HVHF. The results also do not adequately
account for potential confounders (except smoking).
An unpublished presentation of findings from the Southwest Pennsylvania
Environmental Health Project (SWPA-EHP) was made available on the organization’s
web site. A formal report of these findings was not available; the findings are
summarized in a slide presentation.5 Self-reported symptoms were summarized for
patients from one county in southwestern Pennsylvania who sought medical care at the
SWPA-EHP clinic. Self-reported symptom categories occurring in 21 – 48 percent of
individuals seeking medical care included: skin rash or irritation, nausea or vomiting,
abdominal pain, breathing difficulties or cough, and nosebleeds. Other complaints
mentioned in the presentation include anxiety/stress, headache, dizziness, eye irritation,
and throat irritation. The presentation attributes up to 27 cases6 of symptom complaints
as plausibly associated with a source of exposure in either air or water. However, there
is no environmental exposure assessment presented in support of the claimed
associations. No air or water monitoring data are presented. The symptoms reported
are common in the general population and can have many causes. As with the
Earthworks analysis, the sample is self-selected, and there was no systematic
assessment of baseline health status or comparison with a similar non-HVHF
population. There is no information presented indicating that the analysis attempted to
account for potential confounders or other existing exposure sources.
Rabinowitz et al. (2014) conducted a preliminary (hypothesis-generating) study in the
same county in southwestern Pennsylvania as the SWPA-EHP report described above.
The study found some evidence that residential proximity of natural gas wells may be
associated with the prevalence of certain health symptoms, largely acute or self-limiting
dermal and upper-respiratory conditions. As the authors noted, follow-up investigations
would be required before drawing any conclusions with regard to actual disease
incidence or possible causal relationships.
Results from a series of patient evaluations or symptom reports as presented above can
only be considered hypothesis generating; that is, they can suggest possible
relationships between an environmental exposure and health effects that could be
investigated systematically in epidemiology studies designed to control for bias,
confounding, temporality and chance findings. These types of clinical reports do not
allow conclusions to be drawn about causal associations between HVHF exposures and
health risks. However, while many of the reported symptoms are common in the general
population, these reports indicate current information is not adequate to exclude the
possibility that HVHF is contributing to public health impacts.
Local Community Impacts
There is a broad agreement in the public health community that social factors such as
income, education, housing, and access to health care influence health status (i.e., socalled
social determinants of health).7 Many historical examples exist of rapid and
concentrated increases in extractive resource development (e.g., energy, precious
metals) resulting in local community impacts such as interfering with quality-of-life (e.g.,
noise, odors), overburdened transportation and health infrastructure, and
disproportionate increases in social problems, particularly in small isolated rural
communities where local governments and infrastructure tend to be unprepared for
rapid changes.8 These impacts could indirectly result in increased stress, which, in turn,
can be associated with increased prevalence of some health problems (for example,
WHO, 2009). Similar concerns have been raised in some communities where HVHF
activity has increased rapidly (Texas DSHS, 2010).
For example, in some areas of HVHF well pad development nearly all water used for
hydraulic fracturing is hauled to the pad by truck. One horizontal well is estimated to
require about 1500 to 2000 truck trips over the entire life of the well (NTC Consultants,
2011).
A recent study from Pennsylvania reports that automobile and truck accident rates in
2010 - 2012 from counties with heavy HVHF activity were between 15% and 65%
higher than accident rates in counties without HVHF. Rates of traffic fatalities and major
injuries were higher in heavy drilling counties in southwestern Pennsylvania compared
to non-drilling counties in 2012 (Graham, 2015). Major potential adverse impacts from
increased truck traffic include increased traffic congestion and accidents; more damage
to roads, bridges and other infrastructure; and spills of hazardous materials during
transportation.
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