Gov. Andrew M. Cuomo said Tuesday his administration intends to sue the U.S. Environmental Protection Agency to stop a plan to allow up to 20 million cubic yards of dredged waste to be dumped at an open-water site in eastern Long Island Sound — off Fishers Island — over the next three decades.

The governor’s decision comes on the same day the EPA issued its final rule, which was published in the federal government’s official journal known as the Federal Register.

In a letter sent Tuesday, New York state said the EPA’s selection of the disposal site, named the Eastern Long Island Sound Disposal Site, 1.3 square nautical miles large, violates criteria outlined in the federal Ocean Dumping Act, according to a news release issued by the governor’s office.

“As I have said time and again, New York is deeply concerned with the EPA’s efforts to designate a permanent dumping site in the eastern part of the Long Island Sound,” Cuomo said in the release. “Continuing to use this precious economic and ecological resource as a dumping ground is unacceptable and — on behalf of current and future generations of New Yorkers — we intend to fight this decision using any and all legal means.”

Harbors, ports and rivers need to be dredged to allow boats, cargo ships and passenger liners to pass safely. However, environmentalists said sand and sediment pulled from the bottom of rivers, harbors and ports can contain mercury, lead and pesticides.

Most of the estimated 20 million cubic yards of dredged sludge will come from Connecticut’s industrialized shoreline. The contentious question is where to put the muck, and the cost of different disposal methods.

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Robert Evans, who lives on Fishers Island and a board member of the Fishers Island Conservancy, which has been fighting the EPA over open-water dumping in eastern Long Island for more than two decades, said New York hasspent millions to meet EPA mandates that benefit the environment.

“When the EPA acts like this it’s a slapin the face, and it threatens to derail the entire movement,” he said.

Two open-water dump sites in eastern region of the Sound — New London Disposal Site and Cornfield Shoal Disposal Site — are only authorized for use until Dec. 23, according to the EPA. Once they close there are no other designated long-term disposal sites to accept dredged material in that area.

The nearest two dump sites that could be used — Central Long Island Sound Disposal Site and the Rhode Island Sound Disposal Site — are too far from dredging activities, increasing the time and distance of transporting the muck.

“This, in turn, would greatly increase the cost of such projects and would likely render many dredging projects too expensive to conduct,” said the EPA.

Beginning next month, the Eastern Long Island Sound Disposal Site, 2.3 nautical miles northwest of Fishers Island, can begin to accept dredged waste. However, before any sand and sediment could be disposed, a dumping permit is required. The dump site sits in Connecticut state waters, but it’s only 0.2 miles from New York territorial waters.

An EPA spokesman on Tuesday declined to comment on Cuomo’s announcement, saying the agency does not comment on potential or ongoing litigation.

“The site protections and restrictions we included in the final rule are intended to help meet the goal of reducing or eliminating dredged material disposal in the open waters of Long Island Sound,” EPA’s New England Regional Administrator Curt Spalding said previously.