Results of University of Pittsburgh School of Public Health scientists studies exploring health impacts of human exposure to environmental risk factors, including unconventional natural gas development activities, in an eight-county region in Southwest Pennsylvania.
Oil and natural gas production (ONGP) is a prominent industry in Pennsylvania. To date, there have been approximately 350,000 conventional oil and natural gas and 13,000 unconventional natural gas wells drilled in the state. Conventional wells are drilled vertically into shallow, more easily accessible geologic formations. Unconventional wells are drilled using a combination of directional drilling and high-pressure, high-volume hydraulic fracturing (commonly known as "fracking"). These wells, which are typically deeper than conventional wells, access previously unavailable reservoirs of oil and natural gas in the Marcellus and Utica Shales to depths of 10,000-12,000 feet below the surface. These deposits cover a wide swath of Appalachian states (West Virginia, New York, Pennsylvania, and Ohio), but the deposits located under Pennsylvania are reported to represent the largest natural gas reserves in the world. The Department of Environmental Protection (DEP) regulates the ONGP industry in Pennsylvania while the Department of Health acts in an advisory role.
Oil and gas wells are often located near residential areas, and the public, media and researchers have raised ongoing concerns regarding the potential for environmental contamination of water, air and soil due to drilling and associated operations (e.g., pipelines, compressor stations, wastewater storage, truck traffic, etc.). Questions remain about the likelihood and severity of short- and longer-term health impacts associated with ONGP and especially with unconventional oil and natural gas development (UONGD). UONGD began in the early 2000s and boomed several years later. In response to these concerns, the Division of Environmental Health Epidemiology created a separate program area dedicated to UONGD. In March 2011, per the direction of Governor Corbett's Marcellus Shale Advisory Commission, the Division began documenting residents' health complaints related to UONGD, and in March 2017, the UONGD electronic health complaints database was launched. In January 2018, the name of the program area and the health complaints database was changed to oil and natural gas production (ONGP) to cover potential health impacts of both unconventional and conventional drilling.
Recently there has been increased interest in UONGD by academic researchers across the country. UONGD operations occur not only in Pennsylvania, but also in Ohio, West Virginia, Texas, California and a handful of other states. UONGD involves a complex network of industrial infrastructure, from the well pad and wells where oil and natural gas are extracted to the processing plants, compressor stations and pipelines that refine and transport oil and natural gas to consumers. Each of these pieces of infrastructure may present potential exposure hazards to residents living nearby as well as to oil and gas workers.
Several review articles identify the potential exposure pathways through which people's health may be impacted by ONGP/UONGD.1,2,3 These include contamination of surface or groundwater, air pollution or soil degradation. Chemical additives in fracking fluid and the wastewater produced during fracking (flowback, produced water) consist of a broad range of potentially toxic solvents, heavy metals, aromatic hydrocarbons and naturally-occurring radioactive materials. These additives may contaminate nearby private water supplies and/or soil through various pathways (e.g., failing well casings, surface spills or leaks, etc.).4 Additionally, direct and fugitive air emissions from oil and gas well sites can worsen local air quality and have the potential to increase health risks among residents living nearby (i.e., within ½ mile).5 Air pollutants come from the natural gas resource itself as well as diesel engines, storage tanks containing the fluid that comes back up from the wells, and on site materials and equipment used during production.
Researchers have also noted the potential health impacts related to excessive noise, light and chronic stress; vehicular injuries from increased truck traffic or other injuries or emergencies from explosions, leaks or floods; and the particular case of oil and gas workers, pregnant women, children and the elderly who may be at increased risk of health impacts from environmental exposures.6,7,8
Most epidemiologic research to this point has compared the health outcomes of those living varying distances from unconventional well sites as a substitute for exposure to UONGD. There have been very few studies that have measured exposure directly.9 Overall, epidemiologic work has found some limited evidence of relationships between living near UONGD and poor birth outcomes, including low birth weight and preterm birth;10,11,12,13,14 worsening respiratory symptoms;15,16 and some self-reported health outcomes.16,17 Infant health is unique in that the timing of exposure can be pinpointed (within a 9-month period) more precisely than for other health symptoms or outcomes. The Division of Environmental Health Epidemiology, along with the Oil and Gas Health Information & Response team at the Colorado Department of Public Health and Environment published a systematic literature review in 2019. In the review, the joint team of researchers found modest scientific findings of adverse health outcomes experienced by populations living near ONGP.18 The authors also note that study quality has improved over time and the highest rated studies primarily focus on birth outcomes.
Communities in Pennsylvania, especially in Southwest Pennsylvania with significant ONGP activities, have raised concerns about childhood cancers including the Ewing's family of tumors. In 2019 the Pennsylvania Department of Health (DOH) conducted a cancer data review using the PA Cancer Registry.19 This analysis provided a comparison of the incidence rate of the Ewing's family of sarcomas in Washington County, as well as in the Canon-McMillan School District, as compared to the incidence rate found in the rest of the state. Overall, there were no conclusive findings indicating that the incidence rates of Ewing's family of tumors in Washington County and Canon-McMillan School District for female and male populations were consistently and statistically significantly higher than the rest of the state over the three time periods (1985-1994, 1995-2004 and 2005-2017) reviewed. In 2020, DOH examined cancer incidence data in a four-county area in Southwest Pennsylvania (Washington, Fayette, Greene and Westmoreland).20 Childhood cancer rates, as well as overall cancer rates, were mostly similar to or lower than the rest of state rates for all the three time periods examined.
To further address community concerns, DOH is funding the University of Pittsburgh Graduate School of Public Health to conduct two observational epidemiologic studies focusing on known or suspected health effects of UONGD. One study will investigate the relationship between UONGD and the development of childhood cancers in southwestern Pennsylvania, the most heavily drilled area of the state. The other study will aim to replicate earlier studies centered on northcentral/northeastern Pennsylvania evaluating the acute conditions of asthma and birth outcomes. The new studies will use data from southwestern Pennsylvania.