The recent National Academies’ Institute of Medicine (IOM) report on its late-April 2012 workshop, “Health Impact Assessment of Shale Gas Extraction,” describes many potential health impacts of shale gas development and identifies the data gaps – especially the lack of baseline health data – that keep scientists from differentiating real from potential health risks.
The workshop was organized by the IOM Roundtable on Environmental Health Sciences, Research and Medicine.
The National Research Council, also part of the National Academies, defines a health impact assessment (HIA) as a systematic, but mostly qualitative, process that uses an array of data sources and analytic methods, and considers input from stakeholders to determine the potential effects of a proposed policy or project on the health of a population.
Aaron Wernham, project director of the Health Impact Project at Pew Charitable Trusts, noted that HIAs are widely used in the oil, natural gas and mining industries, where companies recognize that HIAs protect workers and communities, reduce risk and lower business costs.
The IOM workshop provided observations from many experts, but did not provide recommendations on monitoring and managing the health impacts of shale gas extraction.
The workshop did identify potential risks from: drinking-water contamination, air pollution, climate change from greenhouse gas emissions, noise, changes in land use and community impacts related to an influx of workers, changes in traffic and economic changes to individuals and governments.
In three areas, little-publicized data were presented:
- Declining ozone levels in the area of Barnett shale development.
- Unhealthy levels of worker exposure to silica dust and diesel particulates.
- The volumes of increased truck traffic in shale gas development areas.
♦ Air pollution, ozone in the Dallas-Fort Worth area.
Michael Honeycutt, director of the toxicology division of the Texas Commission on Environmental Quality (TCEQ), reported that ozone was the only criteria pollutant associated with oil and gas activities for which the Dallas-Fort Worth area was in violation.
However, as the number of Barnett shale wells grew from almost zero in the mid-1990s to over 14,000 wells in 2011, ozone levels declined from 106 parts per billion (ppb) in 1995 to 86 ppb in 2010. The area standard for compliance is 85 ppb.
TCEQ continues to regularly monitor emissions using fixed-site, airborne and hand-held monitors and detectors. High readings often reflect faulty equipment that can be quickly repaired.
♦ Worker exposure to silica dust and diesel particulates.
Eric J. Esswein, senior industrial hygienist at the National Institute for Occupational Safety and Health (NIOSH), reported on worker health data collected through partnerships with five companies – at 11 hydraulic fracturing sites in five states. NIOSH found that 50 percent of the breathing-zone, silica dust samples exceeded the OSHA permissible exposure limit, and 68 percent were greater than the NIOSH recommended exposure limit.
These elevated levels of silica dust were higher than levels suitable for the respirators used by most workers.
NIOSH has recommended equipment changes that can reduce the silica dust levels and worker impacts. NIOSH sampling showed that diesel particulate at well sites also is a likely health hazard.
♦ Increased truck traffic in shale gas development areas.
Timothy Kelsey, professor of agricultural economics and state program leader for Economic and Community Development at Pennsylvania State University, reported that Pennsylvania’s economic experience through March 2012 includes hiring, lower unemployment and higher average wages in Marcellus counties, as well as economic disparities between those profiting from development and those that are not.
His detailed statistics on traffic in Bradford County, Pa., show truck traffic increased more than 10-fold between 2005 and 2010.
Some of the concerns stated in the workshop are now out of date because extraction technology, industry best practices and baseline data collection are rapidly changing.
For example, a peer-reviewed study by N.R. Osborn and others (2011) showing a correlation between methane in drinking water and Marcellus shale wells is cited in this workshop as evidence that hydraulic fracturing results in methane in drinking water – but a more recent, peer-reviewed report by Lisa Molofski and others (Groundwater, May/June 2013) provides evidence that methane in drinking water in some areas of Marcellus shale production does not come from the Marcellus formation, and its occurrence better correlates with topographic and hydrologic features rather than shale gas extraction.
Several speakers suggested areas for additional research:
♦ David Carey, director of the Weis Center for Research at Geisinger Health Center, located in the Marcellus shale development area, reported that since 2004 the center has been collecting digital data on hundreds of thousands of patients. This data could be the basis for various analyses of health impacts.
♦ Bernard D. Goldstein, professor emeritus, Department of Environmental and Occupational Health at the Graduate School of Public Health, University of Pittsburgh, noted – several federal and state advisory committees on shale gas development have lacked members from the public health sector and little public health research has come from these committees’ recommendations.
Goldstein stated a need for clinical health data that is tied to location information in order to detect hotspots for further investigation.
♦ Roxana Witter, assistant research professor of Environmental and Occupational Health at the Colorado School of Public Health, recommended pre- and post-development collection of data on sexually transmitted infections, crime and substance abuse – health conditions that tend to rise with rapid population increases.
Witter also recommended collection of data on heart rate, cortisol and C-reactive protein, which are potential markers for stress.
♦ Rob Donnelly, vice president of health for Royal Dutch Shell, recommended that industry create partnerships with affected communities and other stakeholders to define the research questions.
The complete workshop report can be downloaded as a free PDF file or purchased in hard copy at the National Academy of Sciences website.