Plum Island is a small, federally owned island off the northeastern tip of Long Island, New York, best known as the home of the Plum Island Animal Disease Center (PIADC). From 1954 to 2025, this facility served as the United States’ primary defense against dangerous foreign animal diseases, studying pathogens like foot-and-mouth disease that could devastate American livestock if they ever reached the mainland. The island is now transitioning out of that role, with its research mission moving to a new facility in Kansas.
From Military Fort to Research Lab
Long before it housed laboratories, Plum Island was a coastal defense installation. Fort Terry was established there in 1879 and remained active through World War II, protecting the approaches to Long Island Sound during the Spanish-American War and both world wars. The Army declared it surplus in 1948, and in 1954 ownership transferred to the U.S. Department of Agriculture for use as an animal research facility.
The USDA chose the island deliberately. Studying highly contagious livestock diseases on the mainland posed too great a risk. An island location provided a natural buffer: water on all sides, limited access by ferry, and distance from commercial farms. The facility operated under the USDA until the Department of Homeland Security took over management after 9/11, adding biodefense to the center’s mission alongside agricultural research.
What Researchers Studied There
The core mission of PIADC was protecting American agriculture from “transboundary animal diseases,” pathogens that don’t currently exist in the U.S. but could cause catastrophic losses if introduced. Foot-and-mouth disease (FMD) was the primary focus. FMD is extraordinarily contagious among cattle, pigs, and sheep, and a single outbreak could cost billions of dollars and lead to the slaughter of millions of animals. For decades, Plum Island was the only place in the United States where live FMD virus could legally be handled.
Scientists there also worked on African swine fever and other foreign animal diseases, developing vaccines, diagnostic tests, and decontamination methods. The facility played a direct role in outbreak preparedness, training veterinarians to recognize diseases they’d never encounter in normal practice so they could respond quickly if something appeared on American soil.
Safety Record and Containment Breaches
Plum Island’s safety record wasn’t perfect. In 1978, foot-and-mouth disease was accidentally released during construction work on the island, leading to the slaughter of 200 animals. The outbreak never reached the mainland. After that incident, the facility built new biocontainment buildings to house all research animals indoors. Even with those upgrades, two more outbreaks occurred within five years, though both were contained within the new biocontainment units.
These incidents fueled public anxiety about the facility, particularly among residents of nearby Long Island and Connecticut communities. The fact that the breaches stayed on the island was reassuring to officials but did little to ease local concerns, especially as the facility’s infrastructure aged over the following decades.
The Lyme Disease Conspiracy Theory
One of the most persistent claims about Plum Island is that it was the origin of Lyme disease, supposedly created or accidentally released through tick research. This theory gained enough traction that in 2019, the U.S. House of Representatives even passed an amendment calling for an investigation into whether the Department of Defense had experimented with weaponized ticks.
The science, however, doesn’t support the claim. In the early 1990s, researchers tested museum specimens of ticks and mice to look for DNA evidence of the bacterium that causes Lyme disease. Ticks collected in 1945 from eastern Long Island and mice collected in 1894 on Cape Cod were already infected. That means the Lyme bacterium was circulating in wildlife on Long Island nearly a decade before the Army Chemical Corps even activated Fort Terry in 1952, and on Cape Cod more than fifty years before the time period in question.
There’s also a geographic problem with the theory. Lyme disease and its causative bacterium are found across the upper Midwest, the Pacific Coast, and the southern U.S. Genetic analysis shows no evidence of a single “point source” origin, which is what you’d expect if the bacterium had escaped from one lab. Sam Telford, a Tufts University professor and leading expert on tick-borne infections, has called the conspiracy theory “soundly debunked.”
The Move to Kansas
The USDA is in the process of transferring PIADC’s diagnostic, training, and research work to the National Bio and Agro-Defense Facility (NBAF) in Manhattan, Kansas. NBAF is a modern facility designed to handle even more dangerous pathogens at higher biosafety levels than Plum Island could accommodate. The new lab will take over as the lead facility for foreign animal disease research in the United States.
The move was driven partly by Plum Island’s aging infrastructure. Many of its buildings dated back decades, and upgrades on a remote island were expensive and logistically difficult. NBAF, located near Kansas State University’s College of Veterinary Medicine, offers modern containment technology and easier access to livestock research expertise. Critics of the move have raised concerns about studying foot-and-mouth disease in the heart of cattle country rather than on an island, but the facility was designed with multiple layers of containment to address that risk.
What Happens to the Island Now
With the research mission leaving, the question of what becomes of Plum Island itself has been contentious. Federal law originally required the government to sell the island to the highest bidder, a prospect that alarmed environmentalists and local communities. In response, U.S. Senators Chuck Schumer and Kirsten Gillibrand successfully negotiated the repeal of that sale requirement through a federal spending bill. The sale is now permanently off the table, and the Department of Homeland Security retains ownership while locals help decide the island’s future. Congress also allocated $18.9 million to begin cleaning up the property.
The push to protect Plum Island reflects its surprising ecological value. Despite decades as a restricted-access research site (or perhaps because of it), the island has become a significant wildlife habitat. More than 200 species of migratory, overwintering, and breeding birds use the island, including the federally endangered roseate tern and the federally threatened piping plover. Its plant communities include maritime dunes and wooded freshwater wetlands that support rare species like seabeach knotweed, blackjack oak, and spring ladies’ tresses.
The island carries several federal environmental designations. It’s part of the Long Island Sound Stewardship System under the Clean Water Act, recognized by the U.S. Fish and Wildlife Service as a Northeast Coastal Areas significant habitat site, and included in the Coastal Barrier Resources System. Connecticut’s state legislature has formally called on Congress to designate it as a National Wildlife Refuge, a move that would provide the strongest long-term protection for the land.