"Pollution investigators have found toxic compounds in groundwater below the Delaware Air National Guard base matching those that prompted shutdowns this summer of the city of New Castle's entire three-well public supply network and two Artesian Water Co. wells.

Although levels of perfluorinated compounds, or PFCs, detected at the base were up to 40 times higher than recommended drinking water limits and up to triple those found in public supplies, officials cautioned that the search is continuing and has yet to label the Guard facility as the source of the problem.

The Environmental Protection Agency, which is helping to lead the New Castle investigation, declared PFCs an emerging drinking water contaminant in 2009, and as a potential carcinogen. Regulators set a drinking water safety guidance limit of 0.2 parts per billion of perfluorooctane sulfonate (PFOS) and 0.4 ppb for perfluorooctanoic acid (PFOA)."

Jeff Montgomery reports for the Wilmington News Journal September 25, 2014. [2]