The non-profit Environmental Working Group and a team of environmental health researchers at Northeastern University in Boston developed the map, which tracks publicly-known contaminated sites reported from both EPA testing and state and local agencies.
The number of sites has exploded in the 10 months since the map was first published.
Last February, researchers knew of 52 sites in 19 states.
Much of the newly noted activity came from Michigan.
Communities there are dealing with contamination from 3M’s Scotchgard fabric protector used by shoemaker Wolverine World Wide.
It maps both C-8 and PFAS pollution.
PFAS are replacements for C-8 chemicals companies no longer make and include GenX.
"Every place that has gone looking for it systematically, with any reason at all to suspect they might have contamination, has found it," he said.
"So, that’s why we’re confident in saying that we’re nowhere near the end of knowing the true scope of this problem."
EPA will host a national leadership summit on PFAS contamination next month in Washington, D.C.