The attorneys general of Virginia, Maryland, Delaware and Washington D.C. filed a lawsuit in federal court Thursday against the U.S. Environmental Protection Agency for allegedly failing to enforce cleanup efforts in the Chesapeake Bay.

Under the 2014 Chesapeake Bay Watershed Agreement, six states around the estuary and D.C. agreed to reduce flows of nitrogen, phosphorus and other pollutants into bay waterways by 2025. The EPA is responsible for enforcement.

The new suit alleges the EPA is violating the Clean Water Act by letting Pennsylvania and New York fall short of their pollution reduction targets.

“The EPA must hold every partner equally accountable and make sure they uphold their portion of the agreement,” Attorney General Mark Herring said in a statement. “I will not stand by and allow the EPA to ignore its enforcement obligations and erase decades of progress we have made to reduce pollution and restore the Chesapeake Bay.”

In a separate statement, Gov. Ralph Northam added the cleanup efforts “will require a strong and engaged partnership — including the EPA holding each partner accountable to the commitments they made.”

Virginia and other states originally announced in May their intent to sue the EPA. The agency’s administrator, Andrew Wheeler, previously said the suit would have no merit.

In an email Thursday responding to the filing, an EPA spokesperson said the agency “is fully committed to working with our Bay Program partners to meet the 2025 goals. We have taken and will continue to take appropriate actions under our Clean Water Act authorities to improve Chesapeake Bay water quality.”

The Chesapeake Bay Watershed Agreement was established after a long history of poor management of the bay. A water body where fish and oysters were abundant hundreds of years ago was unhealthy by the late 1900s and wildlife were dying from pollution. In 1999, several environmental groups filed a lawsuit that forced the EPA to become more involved in protecting the bay as part of the Clean Water Act.

The six states and D.C. then agreed to the watershed agreement in 2014. It was the most ambitious plan, to date, to clean up the bay. States had until 2025 to meet pollution reduction requirements by upgrading wastewater treatment plants and preventing nitrogen and phosphorus runoff. Such pollutants are responsible for algae blooms that suck up oxygen in the water and kill sea life.

In 2019, states submitted their latest pollution reduction plans to the EPA. Pennsylvania and New York’s fell far short of their 2025 targets. An EPA evaluation said Pennsylvania’s would achieve just 75% of the required nitrogen pollution reduction, while New York’s would achieve 66% of its nitrogen reduction goal.

Still, the EPA has not forced those states to revise their plans. And Pennsylvania — which accounts for the largest share of pollution in the watershed — has fallen behind in its cleanup effort and jeopardizes the entire restoration plan, according to a recent report by the Chesapeake Bay Foundation.

“It doesn’t have to be this way,” said CBF President William Baker. “But unless pressure is brought to bear on Pennsylvania, we will never get to the finish line.”

CBF along with the Maryland Watermen’s Association and other groups filed a separate lawsuit against the EPA for failing to enforce the cleanup. Baker has said he expects both suits to be consolidated.