Plum Island Animal Disease Center

In September 1978, foot-and-mouth disease virus "was found to have infected clean animals being held outside the laboratory compound" on Plum Island, according to the Government Accountability Office. The likely routes were an incinerator with a faulty air balance, poorly maintained filters, and water seeping near the incinerator. The outbreak stayed on the island, which is the reason the laboratory was built on one.

Why an island

Fort Terry had been an Army coastal artillery post on Plum Island since 1897. In the early 1950s, the Army Chemical Corps began renovating its buildings for chemical and biological research. A 2012 history by the National Academies says the Army handed the island to the US Department of Agriculture in 1952, and other accounts date the formal transfer to July 1, 1954. Secondary histories describe the Army's plan as anti-animal biological warfare research, a description that rests on those histories rather than a published Army record.

Congress required the new animal disease laboratory to sit on a coastal island separated from the mainland by deep, navigable water and not connected to it by a tunnel. USDA scientists moved into the renovated Building 257 in 1953.

The escapes on record

The Department of Homeland Security took over the island on June 1, 2003. In 2004, two cattle in Room 1178 of the East Wing and four pigs in a separate room showed clinical signs of foot-and-mouth disease, though none of them was part of live virus research. GAO put the likely cause down to cross-contamination.

In May 2008, reviewing plans to move the work to the mainland, GAO wrote that the department "does not have evidence to conclude that FMD work can be done safely on the U.S. mainland." The replacement, the National Bio and Agro-Defense Facility in Manhattan, Kansas, opened in 2023.

Lab 257 and Lyme disease

In 2004, the lawyer Michael Christopher Carroll published Lab 257, a book arguing among other things that Lyme disease, first identified in 1975 around Old Lyme, Connecticut, across the water from the island, began with ticks from Plum Island.

Fourteen years before the book, a team led by David Persing at Yale tested 136 museum tick specimens for the Lyme bacterium. DNA of the bacterium turned up in 13 ticks collected in the 1940s at Montauk Point and Hither Hills on Long Island, before the laboratory existed. The paper ran in Science on September 21, 1990.

In a November 2025 appearance on the PBD Podcast, FDA Commissioner Marty Makary said there was a high degree of probability that Lyme disease came from Lab 257.

The island now

Research on Plum Island ended in September 2025, and the department has begun decontaminating and decommissioning the high-containment laboratories. A small diagnostic capability remains until the Department of Agriculture's work has fully moved to Kansas.

A federal law once ordered the island sold to the highest bidder. Congress repealed it in December 2020 and set aside $18.9 million for cleanup. On July 16, 2026, Suffolk County Executive Ed Romaine announced that the county would seek to acquire the island. County officials expect it could be declared surplus early in 2027 if no federal agency claims it.

The island has been closed to visitors since June 2018, when the Department of Homeland Security ended the small group tours it had allowed, citing litigation and the planned sale. Reporting in July 2026 put any public return years away.

The closest view is from the water. The Cross Sound Ferry between Orient Point and New London, Connecticut, runs through Plum Gut, close to the island's western end, where the laboratory and the 1869 granite lighthouse stand. The ferry terminal is at 41270 Main Road in Orient.

On land, Orient County Park sits to the left of the ferry parking area at the end of Route 25 and looks out over Plum Gut. Parking is a small dirt lot.

The lighthouse's Fresnel lens was removed in 1994 and is on display at the East End Seaport Museum in Greenport.