Why dangerous ‘forever chemicals’ are allowed in US drinking water

The federal government has still not set limits for PFAS compounds, and some allege that could be because it is a polluter of them itself

• This story is co-published with Consumer Reports

In 2014, residents of Horsham Township, near Philadelphia, learned that their water had been contaminated with potentially toxic chemicals linked to an array of health problems, including learning delays in children and cancer. Those residents include Frank and Lisa Penna, who allege in a lawsuit that their water was among the contaminated supplies.

Known as PFAS, for per- and polyfluoroalkyl substances, the chemicals in this class of approximately 5,000 substances have become notorious as much for their potential danger as for their perseverance. Because the chemical bonds that hold the compounds together don't break down easily, they last a very long time - a reality that has led to a commonly used name for the group: Forever chemicals."