New London — The fight to block the federal government from selling Plum Island to the highest bidder recently received a boost from four U.S. senators who are pushing to protect the island as an environmental, recreational and research resource.

Joined by leading environmental advocates at the New London Maritime Society on Wednesday, Sen. Richard Blumenthal, D-Conn., announced a bill that would repeal the government's mandate to sell the 840-acre island, which is home to several endangered species and hundreds of rare plants and insects.

The General Services Administration has tried to sell the property for the last 10 years, after Congress voted to close the island's animal disease center and relocate it to the new National Bio and Agro-Defense Facility in Kansas, a move expected by 2023. The island's sale was supposed to offset costs of the Kansas facility, but Blumenthal said those construction costs have already been appropriated, eliminating any financial need to turn over a "unique environmental treasure that we should preserve, not sell."

"The sale of Plum Island ... would be a waste of an essential opportunity to create a park or stewardship entity of another kind," Blumenthal said. "It's priceless. The federal government can never gain from a sale what this land is worth. It belongs to the people now and it should remain the people's island."

Introduced last week by Blumenthal, Sen. Chris Murphy, D-Conn., Sen. Charles Schumer, D-N.Y., and Kirsten Gillibrand, D-N.Y., the Plum Island Conservation Act would protect habitats for endangered species and potentially provide an opportunity to revamp the animal disease center into a research facility.

Blumenthal said he hopes the bill could pass later this year, noting there's some bipartisan support in Congress and backing from lawmakers in both Connecticut and New York.

Chris Cryder, land campaign manager for nonprofit Connecticut Fund for the Environment/Save the Sound, said a coalition of 107 organizations is fighting to protect Plum Island from development that would "irrevocably damage the habitats and wildlife as well as the historic resources of the island."

"Land protection battles like this one take a long time and require perseverance," said Cryder, noting Plum Island provides "amazing habitats" to more than a hundred at-risk species. It's also home to a lighthouse built in 1869 and unique structures once part of the former Fort Terry, he said.

Patrick Comins, executive director of the Connecticut Audubon Society, said Plum Island provides "800 acres of remarkable, undeveloped coastal habitat" with rocky and sandy shorelines, freshwater and tidal marshes and upland forests allowing for "very high biological diversity." Roseate terns, Piping plovers, common eiders and blackpoll warblers are among the many species spotted on the island, he said.

Louis Burch of the Citizens Campaign for the Environment said this is "a time of great uncertainty with respect to our natural spaces and habitats."

"We're seeing all kinds of rollbacks to our national parks and monuments coming out of Washington, D.C.," Burch said. "This is a real opportunity in the Long Island Sound community to preserve something in its natural state in perpetuity. Future generations can benefit. It makes a lot of sense for further research purposes ... and might be a good opportunity to use those facilities to study the impacts of climate change."

In 2013, President Donald Trump reportedly expressed interest in buying Plum Island and developing a "beautiful, world-class golf course," according to Newsday.

In 2016, Connecticut Fund for the Environment/Save the Sound led a group of organizations in a lawsuit to block any sale of the island, alleging the GSA and the Department of Homeland Security did not follow federal law during an environmental review process for the proposed sale.

The suit claimed that the government's 2016 environmental impact study failed to address the protection of endangered and threatened species that have flourished on the island.

The federal government then announced last year it would conduct an environmental impact study to address endangered and threatened species. That study is still set to begin this year, according to Blumenthal. A message left with the GSA was not immediately responded to on Wednesday.

b.kail@theday.com