Plum Island, a mostly untouched oasis in Long Island Sound, likely will never be developed as Congress has withdrawn its plan to sell it to the highest bidder — but preservationists hope to ensure it will remain forever pristine.

Groups such as the Nature Conservancy, Save the Sound and the rest of the 122 members of the Preserve Plum Island Coalition have asked President Joe Biden to declare the island a national monument, according to Holly Drinkuth, program director for the conservancy’s Connecticut chapter. Plum Island, part of New York state, sits 10 miles south of East Lyme, off Long Island’s Orient Point.

Aside from the U.S. Department of Agriculture animal disease center on the 840-acre island, “Other portions of the island have remained really wild and undeveloped, and they are incredibly important for seabirds who use the area as nesting sites,” Drinkuth said.

Those include piping plovers and least terns. It’s a stop on many birds’ migratory routes as well.

Louise Harrison, Long Island natural areas manager for Save the Sound, said, “We don’t have a strong read into the White House’s reaction right now” because the coalition has been asked for additional information.

“But we feel very confident that once we provide all the information that they’re asking for that they will see it’s incontrovertible,” she said. “Plum Island should be a national monument. There’s so many great reasons why. It’s owned by the federal government. It has two National Register historic sites, Plum Island lighthouse and Fort Terry and barracks.”

Fort Terry was built in 1897 as one of several coastal defenses at the mouth of Long Island Sound before the Spanish-American War, Harrison said. “The government was concerned about an attack on New York City. So there were a series of forts built across the entrance to Long Island Sound and Fort Terry was one of them,” she said.

The lighthouse dates from 1869 and was the second one built on the island to guard Plum Gut, “a treacherously difficult waterway between the tip of Long Island and Plum Island,” Harrison said. “And as we understand it, there had been over 100 shipwrecks there.”

The USDA lab also is eligible for the National Register, Harrison said, “because of the amazing discoveries there and the famous people who’ve worked there.”

Also, the island is touched by two bodies of water in the National Estuary Program: Long Island Sound and the Peconic Estuary, Harrison said. Rhode Island’s waters also touch the island, making three states with an interest in it.

Harrison said Plum Island has “the largest seal haul-out area, where seals pull themselves up onto rocks. It’s the largest seal haul-out area in the state of New York and one of the largest in southern New England. And, of course, the Marine Mammal Protection Act is a federal law, so that comes into play.”

She added that the island is considered a federal coastal barrier resource area.

“The Montauk Indian nation is highly interested in Plum Island and believes that it is part of their traditional territory,” Harrison said. Plum Island also is a natural gem with several features all in one small place.

“An example of that would be rocky shore,” Drinkuth said. “The coastal forest, which can sometimes get removed for development purposes. There’s some nice open stretches of beach and, again, not really interrupted. … And there’s not really a threat to those wildlife species.”

Harrison said, “There’s many reasons why we think the federal government should retain Plum Island and designate it a national monument for the purposes of ecological conservation, historical preservation and then the discovery and celebration of our shared cultural heritage. And I say discovery because some archaeology needs to take place there.”

The island, which has been open to visitors in the past, was closed “just when we were about to actually get some archaeological resources onto the island,” she said. It’s important to “find out what we can about the use of the island for 10,000 years before the colonists came,” she said. “This is all really in the nation’s interest.

“We are determined,” Harrison said. “We haven’t taken ‘it can’t be done’ for an answer at any step of the long road to preserving Plum Island and we’re not about to now. We see victory coming in protecting Plum Island in perpetuity and need everyone to write the president in support.”

The coalition also has found a donor “who is very willing to help with the future of Plum Island,” she said. “And that may include things like a visitor center. One of the things this donor is interested in is an internship for Native American youth to study the environment and their own culture as it pertains to Plum Island.”

Drinkuth said another advantage is that Plum Island is so close to densely populated parts of Connecticut and New York. “It’s got so many people around it, but it’s remained really untouched and relatively wild,” she said. “That history, the cultural value as well as the ecological value, just make it a really important place for the public to continue to enjoy. And so we’re excited to see the options for having it remain in public trust.”

The decision to move the lab was made in 2008, at a cost of $1.25 billion, and Plum Island was to be used as collateral to raise the funds. It wasn’t until President Donald Trump signed the December 2020 omnibus spending bill, which included COVID-19 relief money, that the plan was abandoned. The lab remains open and might be for years.

“What initially occurred was, when the decision was made to move the USDA lab to Kansas, they didn’t have a pathway to pay for building the new lab in Kansas,” Drinkuth said. “So there was a decision to sell Plum Island to pay for that. And that’s not the typical process. Typically, it goes through review, and there’s an offer to other federal agencies prior to moving directly to private sale.”

The normal route is for federal agencies to review the land to determine its value, both financial and natural, “which is great,” Drinkuth said. “It’s the kind of property that we would look for [as] a national park or wildlife refuge, those kinds of things, just because of those many ecological values.”

Drinkuth said the group has identified “options for ongoing uses of the island, including having visitors come but maintaining and protecting those ecological resources and continuing to protect the really high-quality habitats and wildlife that use the island.”

The U.S. senators from New York and Connecticut have written to Interior Secretary Deb Haaland, encouraging her to ensure that Plum Island will be preserved.

“I think we have a 50/50 chance,” said U.S. Sen. Richard Blumenthal, D-Conn., “In part it will depend on simply focusing the president’s attention and the people around him. But it could happen at the end of the year. … We have a very strong, united delegation in favor of preserving Plum Island and its natural beauty and resources.”

“I’ve advocated for it because the president can do it without needing Congress’ approval, thereby avoiding the possibly long battle that would involve the legislative process,” Blumenthal said.

U.S. Sen. Chris Murphy, D-Conn., said “Plum Island is an ecological and historical treasure and my first concern is protecting it from harmful development.

“My colleagues and I are pushing President Biden and Interior Secretary Haaland to take action to permanently protect Plum Island and give people the opportunity to enjoy it. This isn’t an easy process but we are determined to find the right path forward for Connecticut and New York,” he said.

The White House press office did not respond to a request for comment.

While development or putting the island up for auction are not completely out of the picture, Drinkuth said those options are highly unlikely.

The Nature Conservancy’s hope is “a federal route to permanent protection, whether that’s through making it a national monument or through one of the federal agencies or even state or local agency management,” Drinkuth said.

A national monument, as opposed to a national park, would include local management while being overseen by an agency in the Interior Department. They are created by executive order of the president under the Antiquities Act of 1906.

“That would be sort of a fast and simple route,” Drinkuth said. “Moving it into the national park system or the fish and wildlife system would require more congressional effort. It’s not out of the question. Those agencies would have to be willing and able to manage the resource.”

Now, the island is overseen by the Department of Homeland Security.

Saving Plum Island “is not a rapid process,” Drinkuth said. “It will take several years to determine how it will be managed. In the meantime, I would say what’s really important to the Nature Conservancy is that we have a commitment from the federal government to still manage and care for it so that nothing happens in that interim. … In addition, we don’t want it to not be managed so that those really valuable resources have any kind of damage.”