How Hydraulic Fracturing Impacts Our Water: The Pennsylvania Experience

The number of unconventional Marcellus Shale wells in Pennsylvania has increased from 8 in 2005 to more than 7000 today. To understand the Pennsylvania experience, we are analyzing publicly available data. After removing permitting and reporting violations, the average percentage of wells/year with at least one notice of violation (NOV) from PA DEP has averaged almost 20%. Most violations are minor. Nonetheless, several incidents have led to fears that shale gas cannot be developed without endangering our water supply. Indeed, development of shale gas using the newest form of hydraulic fracturing has not only caused methane migration, but also spills of briny formation waters, hydraulic fracturing fluids, sediments, drilling muds, fuels, drill cuttings, and hydrostatic testing waters into surface waters and groundwaters. Shale gas activities have contaminated natural waters with benign substances such as sodium chloride—sometimes at toxic concentrations—as well as more toxic naturally occurring radioactive materials (NORMs) as well as solutes such as bromide that can combine with organic compounds and disinfectants to create toxic species. Such incidents have led many to wonder: Can we maintain clean water and still develop shale gas? To date, it remains impossible to answer this question adequately due to a dearth of publicly accessible, transparent data. However, the data that are available for Pennsylvania show that the frequency of problems is relatively small compared to the number of gas wells.