U.S. Environmental Protection Agency (EPA) Investigation

In October 2011, Dimock residents requested EPA to further investigate the matter, which EPA agreed to do in November 2011. A month later, the EPA Region 3 Office asked the Agency for Toxic Substances and Disease Registry (ATSDR), an agency within the United States Department of Health and Human Services, to conduct an analysis of available water well data in the Dimock area. After reviewing the available data, ATSDR supported a “Do Not Use Until Further Notice” action for residential water wells fearing a risk for public health due to elevated levels of chemicals in the water. ATSDR also recommended that additional groundwater quality sampling be conducted. Meanwhile, following a request from Cabot, DEP authorized the corporation to stop supplying temporary water supplies to the affected residents in November 2011 on the basis that Cabot had satisfied its obligations under the Consent Order and Agreement.

EPA, together with ATSDR, carried out successive water samplings on 64 private water wells from January to July 2012 and, based on the results of the sampling, found traces of toxic substances in certain wells, including lithium, arsenic, barium and manganese.

U.S. EPA News Releases: “EPA to Begin Sampling Water at Some Residences in Dimock, Pa” (Jan. 19, 2012)

On July 25, 2012, EPA concluded, however, that “the sampling and an evaluation of the particular circumstances at each home did not indicate levels of contaminants that would give EPA reason to take further action,” and thus ended its investigation. Shortly thereafter, in August 2012, DEP lifted the drilling moratorium on Cabot’s natural gas operations in the Dimock area.  

U.S. EPA News Releases: “EPA Completes Drinking Water Sampling in Dimock, Pa.” (Jul. 25, 2012)
Dimock Residential Ground Water Site; Technical Summary of the Data Collection, Validation and Review Process (Jul. 24, 2012)

Once Cabot resumed its natural gas drilling and completion activities, some residents remained concerned about changes in the quality of their drinking water, and thus they specifically requested the ATSDR to review the 2012 EPA water sampling data. In May 2016, the ATSDR released a new report – this time without any further intervention of EPA – reevaluating the 2012 water data and “recommend[ing] that people take steps to reduce health risks from exposure to contaminants found in their residential private wells.” More precisely, ATSDR found “some of the chemicals in the private water wells at this site at levels high enough to affect health (27 private wells) pose a physical hazard (17 private water wells), or make the water unsuitable for drinking.” According to the report, “this health consultation completes the ATSDR assessment of the EPA 2012 private well water data” and the findings and recommendations in this report “supersede” the prior ATSDR recommendations.

Health Consultation, Dimock Groundwater Site, U.S. Department of Health and Human Services, Agency for Toxic Substances and Disease Registry (May 24, 2016)