Weill Cornell Medical Center

The Need for Proactive Public Health Policies

From the Review Article by Madelon L. Finkel, Jake Hays, and Adam Law, Weill Cornell Medical College and Physicians Scientists & Engineers for Healthy Energy (PSE).

A modern form of natural gas development has become a global “game changer” in the quest for energy. Natural gas, abundant around the world, has a clean reputation compared to other fossil fuels since it burns less carbon when used. It is easy to transport, reasonably economical, and requires comparatively quick construction timelines and low capital costs.

Traditionally, natural gas was extracted using a method that bores a vertical well in single gas reservoirs close to the surface (conventional natural gas drilling). However, drilling for natural gas in shale rock was not particularly economical, primarily because shale typically has insufficient permeability to allow significant fluid flow to a well bore. With technological advances and unconventional methods (i.e., horizontal hydraulic fracturing), gas extraction from tight formations (e.g., shale) is now feasible.

This type of unconventional natural gas development relies on clustered, multi-well pads and long, horizontal laterals. Wells are drilled vertically (often thousands of feet) and horizontally in multiple directions. The method entails injecting large volumes of fluid consisting of chemicals, water, and sand into the well to fracture the shale rock that releases the natural gas. The internal pressure of the rock formation also causes a portion of the injected fracking fluids to return to the surface (flowback fluids); these fluids are often stored in a tank or pit before being pumped into trucks for transport to a disposal site. Flowback has been shown to contain a variety of formation materials, including brines, heavy metals, radionuclides, and organics, which can make wastewater treatment difficult and expensive.

Further, other studies found that 20% to 85% of fracturing fluids may remain in the formation, which means the fluids could continue to be a source of groundwater contamination for years to come. By 2009, there were more than 493,000 active natural gas wells across 31 states, almost double the number in 1990, of which approximately 90 percent have used hydraulic fracturing to extract gas.

Whereas shale gas has the potential to become a significant, economical energy source, the potential for harm and the potential of giving a false sense of energy security are often dismissed by its proponents. The process is potentially polluting and damaging not only to human and animal health but also to the environment, as a result of clearing of land for well pads, drilling the wells, extracting the gas, storing the byproducts of the extraction, transporting the gas by diesel trucks, and the final capping of the well. The potential for harm to children is especially worrisome. This article focuses on a literature review of unconventional natural gas development and its potential impact on human health.

Conclusions

The health impacts related to unconventional natural gas development may not be evident for years, as medical conditions with long latency periods will present over time. While the potential long-term, cumulative effects will not be known for years, we argue that it would be prudent to begin to track and monitor trends in the incidence and prevalence of diseases that already have been shown to be influenced by environmental agents.

Meanwhile, the natural gas industry needs to address the risks to human and animal health and take steps to limit, preferably to eliminate, the exposure pathways. We need far greater transparency and full chemical disclosure. There needs to be an end to discharging effluent into rivers, streams, and groundwater.

There needs to be much more attention paid to curtailing or preferably eliminating spills and leaks of radioactive wastewater. There needs to be an end to the disposal of radioactive sludge from drilling sites in landfills. There needs to be a safer way to develop this resource to limit the exposure to silica, which can cause silicosis, chronic obstructive pulmonary disease, and lung cancer. Banning the practice of burning off the initial flow of natural gas (flaring) needs to be mandated sooner than 2015, the date when EPA ruling goes into effect.

And, perhaps most importantly, there needs to be a well-designed epidemiologic study conducted to empirically assess health status among those living proximate to active development compared to those living in areas where development is not occurring.