A major settlement signed Friday will require Pease International Tradeport to clean up water pollution from its stormwater runoff.
The Pease Development Authority was sued more than two years ago by the Boston-based Conservation Law Foundation for federal Clean Water Act violations.
CLF says stormwater runoff from Pease has contaminated the Great Bay estuary with nitrogen, bacteria, heavy metals, petroleum products and likely toxic PFAS chemicals.
Now, CLF and Pease have reached a settlement in U.S. District Court that will require the tradeport to get a federal municipal storm sewer permit.
They'll have to clean up polluted runoff from new and existing development, and do more testing and cutting-edge treatment of PFAS chemicals in nearby surface waters.
Those chemicals have also been found in Pease's drinking water. They're thought to have come from past military operations.
The settlement will add to ongoing military efforts to study and clean up contamination at the tradeport, which has been a federal Superfund site since 1990.
In a statement, CLF says the new settlement is the first of its kind to require a redeveloped base to get a federal sewer permit, or to mandate pilot treatment technologies for PFAS.