In an effort to protect the water supply, several suburban Philadelphia towns will stop using several wells that may be unsafe. 

Kyle Bagenstose of the Bucks County Courier Times has been following the story and joined Newsworks Tonight's Dave Heller to give an update.

The chemicals in question, perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), can be found in firefighting foams that were used at military bases in the area. Health advisories established in 2009 set hazardous levels of the possible carcinogens at 0.4 parts per billion for PFOA in drinking water, and 0.2 ppb for PFOS. But the new numbers lower that line to .007ppb for each.

Research on connecting the chemicals to health problems such as cancer is still young. The Agency for Toxic Substances and Disease Registry is currently looking at data on cancer in the area over the past thirty years to determine there is a link, and Bagenstose says their findings could be released as soon as the summer.