FRISCO — Drinking water in Frisco is tainted with dangerous levels of the PFAS “forever chemicals” from suspected firefighting foam runoff into nearby creeks, according to new EPA guidance that radically lowered safety levels and sent state officials in search of cities with similarly compromised water systems.

More than 100 city and town water systems across the state also have test results for PFAS above the new EPA guidelines, state officials said Monday, though in some cases the amounts were so low they must be retested for lab errors or other factors.

In June, the EPA lowered its recommended guidelines for two of the thousands of PFAS variations, PFOA and PFOS, from a maximum of 70 parts per trillion in drinking water down to 0.004 and 0.02 parts per trillion, respectively.

State officials said they are now returning to the 25% of cities that tested over those revised limits during a 2020 sampling program run by the Colorado Department of Public Health and Environment. In that 2020 round, the state sampled about 400 of 800 water systems, covering 80% of the population, and will now return to at least 101 of those systems for more testing.

Read more at ColoradoSun.com.