Vermont is suing the largest dairy in the state for dramatically expanding its operations without proper permits in 2017.

Vermont Attorney General T.J. Donovan announced the charges Thursday against the Berkshire-based Pleasant Valley Farms for work at its Lumbra Farm in Enosburg Falls.

The dairy, owned by Mark and Amanda St. Pierre, has more than 5,000 cows at several properties in Franklin County. The farms are located in the Missisquoi River Basin, which drains into Missisquoi Bay, one of the most polluted sections of Lake Champlain.

“We have a long and proud tradition of farming, agriculture and environmental stewardship in Vermont,” Donovan said in a statement. “We need to continue to support our farmers while also protecting water quality and the environment by applying these rules across the board.”

The state alleges the St. Pierres expanded a dairy barn from 13,000 square feet to 104,000 square feet and built a 10-million-gallon manure pit — enough for 1,500 cows — all without permits from the state.