backActual measurements and evaluation of potential exposure pathways demonstrate that claims of risk of harm due to radon in shale gas produced by hydraulic fracturing are unfounded. An October 14, 2015 edition of the Compendium of Scientific, Medical, and Media Findings Demonstrating Risks and Harms of Fracking (Unconventional Gas and Oil Extraction)1 (Compendium) published by the Concerned Health Professionals of New York and Physicians for Social Responsibility offers another opportunity to emphasize the importance of using actual measurements to inform statements about risk. Pre- and post-drilling and production measurements and informed modeling are needed to address claims regarding risk in regulatory and litigation settings.
The Compendiums discussion of risks associated with radioactive releases, includes reference to reports of high levels of radon in buildings in heavily drilled areas of Pennsylvania, and of [u]nsafe levels of radon and its decay products in Marcellus Shale natural gas that may pose risks to end-users when allowed to travel into homes. The Compendium cites supporting articles and studies for each scenario. These references rely on estimated data, instead of actual measurements, and lack evidence of an informed assessment of the risk associated with radon concentrations in Marcellus Shale natural gas.
Measurements show that radon in Marcellus Shale gas is not a hazard to end users in New York
Claims that levels of radon in Marcellus Shale gas pose a risk to end users have been shown to be grossly overstated based on actual measurements of radon in the gas. A 2014 blog post and letter that the Compendium cited ignore relevant findings by the Federal Energy Regulatory Commission (FERC).2 In the FERC proceeding, opponents of a petition to extend a natural gas pipeline carrying Marcellus Shale gas into New York submitted a report by a scientist who claimed that the radon in the natural gas used by customers in unvented stoves could result in as many as 30,000 excess lung cancer deaths in New York. This claim relied on reports that the radon concentration in Marcellus Shale natural gas was up to 70 times the average in natural gas wells in the U.S. However, the scientists findings were shown to be based not on actual measurements of radon in Marcellus Shale natural gas, but upon his own interpretation of gas well logs from which he could not determine specific measurements.
The company requesting the pipeline extension obtained samples of the gas along the transmission line from Marcellus Shale wells in Pennsylvania to the point where the line would enter New York. The testing confirmed the companys position: the radon concentration at the point where the gas line would enter New York was over 150 times lower than the estimated concentration upon which the claimed 30,000 excess lung cancer deaths was based. Subsequent results of analysis of radon in Marcellus Shale natural gas by the United States Geological Survey also fully supported the findings of the pipeline companys health physics expert. Based on the information submitted, FERCs October 2012 opinion found that the pipeline projects potential transportation of Marcellus-sourced gas will not pose a health hazard to end users.3 The 2015 Compendium does not include this reported FERC determination.
Measurements disprove suggestion that high levels of radon in Pennsylvania homes are related to drilling activity
The Compendium also references findings of an April 9, 2015 Johns Hopkins Bloomberg School of Public Health study,4 reporting that the study found high levels of radon in buildings specifically in heavily drilled areas of Pennsylvania.5 Actual measurements by the Pennsylvania Department of Environmental Protection (PA DEP)6 demonstrate that radon from natural gas wells entering buildings via one of the two pathways that the Johns Hopkins study identified could not have contributed to the radon levels in the buildings that were studied. The Johns Hopkins studys theoretical pathways were through 1) gas used for cooking and heating, or 2) radon released during drilling to the ambient air which would travel to nearby buildings. Regarding use of gas in homes, the PA DEP found, There is little potential for additional radon exposure to the public due to the use of natural gas extracted from geologic formations in Pennsylvania, and that any incremental increase in indoor radon concentration would not be detected by commercially available radon testing. The PA DEP also measured radon concentrations between 6 feet and 40 feet of well heads during flowback operations, and found that radon concentrations are within the range of typical ambient background Rn concentrations (0.2 to 0.7 pCi/L in outdoor ambient air in the U.S.). If radon concentrations near the well sites were in the range of background, they could not significantly influence radon concentrations in buildings in the area. This conclusion is particularly true because the Johns Hopkins studys definition of proximity to heavily drilled areas of Pennsylvania excluded radon measurements from buildings that were less than 800 meters (~1/2 mile) away from drilling activity, and included radon measurements in buildings up to 20 kilometers (12 miles) away from any well.
The Johns Hopkins study took no account of the effect of prevailing winds on the transmission of radon from wells to the buildings in which radon levels were measured. It also failed to control for factors that could have independently influenced radon concentrations in the buildings at issue - the degree of sealing for energy efficiency, wind speed and direction, the social economic status of the individuals in the homes, or soil type and moisture.
Role of measurement data in addressing claims that hydraulic fracturing of a gas well caused elevated radon in well water and in a nearby home
The need for critical review of studies by experts and use of measurements is also important in reaching a valid outcome in litigation. In one case in West Virginia, plaintiffs claimed that hydraulic fracturing of a nearby gas well caused, among other things, elevated levels of radon in their water well water and in their home. Although the water well had been tested prior to drilling, the samples were not analyzed for radon concentration. No pre-drilling radon gas tests had been performed in the home. Relying on radon test results from water sampling of other water wells in the county and in a nearby county, the defendants experts noted that the radon concentrations in the plaintiffs well after hydraulic fracturing occurred were, in some cases, lower than the pre-drilling radon concentrations in other water wells in the area. Radon gas test results included some measurements in the plaintiffs home that were above the EPAs limit for implementing mitigation measures. Although results of radon gas tests in other homes in the same county indicated that the test results for the plaintiffs home were not unusual, the absence of a valid pre-drilling test result presented a challenge to proving that radon levels in the home were not somehow influenced by drilling activities. The case was resolved before additional information regarding the reliability of the testing and a pathways or risk analysis was performed.
Conclusion
The importance of data regarding pre-drilling and post-drilling radon concentrations in natural gas and in the groundwater wells and homes in nearby areas cannot be overlooked. These measurements can inform reliable and reasonable responses to uninformed and exaggerated claims regarding the risk from radon associated with shale gas production and hydraulic fracturing.
1 Concerned Health Professionals of New York & Physicians for Social Responsibility, Compendium of scientific, medical, and media findings demonstrating risks and harms of fracking (unconventional gas and oil extraction) (3rd ed.) (2015, October 14). http://concernedhealthny.org/wp-content/uploads/2012/11/PSR-CHPNY-Compendium-3.0.pdf.
2 Order Denying Requests for Rehearing, Reconsideration, Stay, and Late Intervention, U.S. Federal Energy Regulatory Commission, Docket No. CP11-56-001, 141 FERC 661,043 (October 18, 2012). http://www.ferc.gov/whats-new/comm-meet/2012/101812/C-1.pdf.
3 Id.
4 Casey, J.A., et al., Predictors of Indoor Radon Concentrations in Pennsylvania, 1989-2013, Environ Health Perspect (April 9, 2015) http://dx.doi.org/10.1289/ehp.1409014.
5 Compendium at p. 57.
6 Pennsylvania Department of Environmental Protection, Technologically Enhanced Naturally Occurring Radioactive Materials (TENORM) Study Report, Rev. 0 (January 2015) http://www.elibrary.dep.state.pa.us/dsweb/Get/Document-105822/PA-DEP-TENORM-Study_Report_Rev._0_01-15-2015.pdf.