A bill that would rule out the sale of Plum Island to a private developer soon will come before the U.S. Senate, Sen. Richard Blumenthal said Tuesday.

The bill, introduced in the Senate last week and co-sponsored by Blumenthal, U.S. Sen. Chris Murphy, D-Conn., and U.S. Sens. Charles Schumer and Kirsten Gillibrand, both D-N.Y., expands on a U.S. House of Representatives measure passed last month that would have blocked spending on the marketing and sale of the island until a study would provide conservation alternative options for the island’s future.

The Senate bill would go even further, repealing legislation that directed the federal government to sell the island to the highest bigger and use the proceeds to fund the relocation of the animal disease research laboratory on the island to a new facility in Kansas.

The Department of Homeland Security has jurisdiction over the island, an 840-acre stretch of land off the north fork of Long Island.

Congress voted in 2008 to close the Plum Island Animal Disease Center, which conducts research on animal diseases like foot-and-mouth disease, and move it to Kansas by 2023. It also directed the federal General Services Administration to sell the island, part of the town of Southold, N.Y., at auction, and government officials continue to market the island to bidders.

The island is better suited for nonprofit or governmental use rather than private development, Blumenthal said Tuesday during a news conference behind the Custom House Maritime Museum on Bank Street.

"I think we ought to preserve it completely," Blumenthal said. "There is no other place like Plum Island."

Environmental advocates say the island, closed to visitors since the research facility was built, has become a crucial habitat for numerous species. Local officials also oppose sale to a private bidder, passing zoning laws that would prohibit residential or commercial development on the island.

Bob Deluca, a Southold resident and the president of a conservation group in the town, said Tuesday he would rather see research continue on the island than watch the facilities demolished to make room for development.

"We already own it, but we have to fight to hold onto it," he said.

The 2016 appropriations bill that passed Congress in 2015 provided about $55 million toward the construction of the new Kansas facility, which is scheduled to open in 2022, from the federal government's general fund. That made the regulation that called for the sale of the island "outdated, misguided and wrongheaded," Blumenthal said.

Flanked by representatives from groups including the Connecticut Fund for the Environment/Save the Sound, the Nature Conservancy and the Connecticut chapter of the Audubon Society, Blumenthal said he expects the new bill will receive bipartisan support, particularly thanks to co-sponsorship from Schumer, the Senate minority leader.

"All we need is a few Republicans," Blumenthal said.

A similar bill passed the House last year but was never taken up by the Senate, partly because senators did not understand that appropriated funding already covered most of the cost of the Kansas facility, making the island's sale to a private bidder unnecessary, Blumenthal said.

"It just got clogged in gridlock," he said. "People still felt like the money would be needed in spite of the appropriations."

Chris Cryder, a special projects coordinator with the Connecticut Fund for the Environment/Save the Sound, said the group plans to travel to Washington, D.C., in September to advocate for the Senate bill.

m.shanahan@theday.com