As DuPont and its spin-off Chemours continue to face lawsuits from US residents claiming health damage from discharges into water of perfluorooctanoic acid (PFOA), the chemical used to produce fluoropolymer-based non-stick coatings such as DuPont’s Teflon brand, the US Environmental Protection Agency (EPA) has announced tighter guidelines for exposure.

The chemical continues to be found in the drinking water of many towns near sites where it was manufactured – despite a 2008 phase-out. Other former PFOA producers include 3M.

EPA said it drew up the new limits in response to recent scientific studies linking PFOA and PFOS to testicular and kidney cancers, as well as birth defects and liver damage. The agency, which has been criticized for failing to act sooner, now says long-term exposure to either chemical at concentrations above 70 parts per trillion could have adverse health impacts. This is significantly lower than the prior advisory level based on short-term exposure of 400 parts per trillion.

Under the new guidance, water systems with concentrations of PFOA or PFOS above 70 parts per trillion will be advised to promptly notify local residents and consult with their state drinking water agencies. EPA said public notification is especially important for pregnant or nursing women because of the impact the chemicals can have on the development of fetuses and infants.

In 2013, the environmental watchdog ordered about 4,800 public water systems throughout the US to test for PFOA. Trace amounts were turned up in more than 100 cities and towns in 29 states, but none exceeded 400 parts per trillion.

Reports say the new lower limit means that some communities will now be shown to have drinking water with contamination levels above the advised threshold. In the past, EPA's national survey did not include many smaller communities located near sites where the chemicals were used for decades, as critics have pointed out.

“EPA will continue sharing the latest science and information so that state and local officials can make informed decisions and take actions to protect public health,” said Joel Beauvais, the agency’s deputy assistant administrator for the Office of Water.