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2c Pre-Bilateral case study
Gas development can affect local and regional air quality. Some areas where drilling occurs have experienced increases in concentrations of hazardous air pollutants and two of the six “criteria pollutants” particulate matter and ozone plus its precursors regulated by the EPA because of their harmful effects on health and the environment. Exposure to elevated levels of these air pollutants can lead to adverse health outcomes, including respiratory symptoms, cardiovascular disease, and cancer. One recent study found that residents living less than half a mile from unconventional gas well sites were at greater risk of health effects from air pollution from natural gas development than those living farther from the well sites.
The construction and land disturbance required for oil and gas drilling can alter land use and harm local ecosystems by causing erosion and fragmenting wildlife habitats and migration patterns. When oil and gas operators clear a site to build a well pad, pipelines, and access roads, the construction process can cause erosion of dirt, minerals, and other harmful pollutants into nearby streams.
A study of hydraulic fracturing impacts in Michigan found potential environmental impacts to be “significant” and include increased erosion and sedimentation, increased risk of aquatic contamination from chemical spills or equipment runoff, habitat fragmentation, and reduction of surface waters as a result of the lowering of groundwater levels.
Unconventional oil and gas development may pose health risks to nearby communities through contamination of drinking water sources with hazardous chemicals used in drilling the wellbore, hydraulically fracturing the well, processing and refining the oil or gas, or disposing of wastewater. Naturally occurring radioactive materials, methane, and other underground gases have sometimes leaked into drinking water supplies from improperly cased wells; methane is not associated with acute health effects but in sufficient volumes may pose flammability concerns. The large volumes of water used in unconventional oil and gas development also raise water-availability concerns in some communities.
There have been documented cases of groundwater near oil and gas wells being contaminated with fracking fluids as well as with gases, including methane and volatile organic compounds. One major cause of gas contamination is improperly constructed or failing wells that allow gas to leak from the well into groundwater. Cases of contamination have been documented in Ohio and Pennsylvania.
Unconventional oil and gas development also poses contamination risks to surface waters through spills and leaks of chemical additives, spills and leaks of diesel or other fluids from equipment on-site, and leaks of wastewater from facilities for storage, treatment, and disposal. Unlike groundwater contamination risks, surface water contamination risks are mostly related to land management and to on- and off-site chemical and wastewater management.
