The Department of Homeland Security is barred from expanding Alligator Alcatraz, the high-profile makeshift detention center in the Florida Everglades, after a federal judge ruled that doing so would harm the surrounding environment.

Judge Kathleen Williams of the US District Court for the Southern District of Florida issued a preliminary injunction Thursday, blocking the DHS’s Immigration and Customs Enforcement and the Florida Division of Emergency Management to continue increasing operations.

Under the order, ICE can’t move any new detainees into the facility, and in 60 days the government must remove all temporary fencing, generators, lighting, and other infrastructure installed “once the population attrition allows for safe implementation.”

The ruling elaborates on an earlier temporary restraining order that stopped the addition of new infrastructure for a two-week period but allowed the existing facility to continue operations.

Despite DHS asserting the facility was solely a state operation, Williams called the detention center a major federal action that warranted review under the National Environmental Policy Act review before its rapid construction in just eight days.

The detention center involved paving approximately 800,000 square feet of land, installing industrial lighting, and employing over 1,000 staff, many of whom live on site, the judge said. The scale of operation rises to the definition of a major agency action, and the law requires public input and environmental assessments before such work.

Williams acknowledged that staff wear uniforms with state agency logos and the DHS hasn’t yet reimbursed the state for its costs, but pointed out that “the project was requested by the federal government; built with a promise of full federal funding; constructed in compliance with ICE standards; staffed by deputized ICE Task Force Officers acting under color of federal authority and at the direction and supervision of ICE officials; and exists for the sole purpose of detaining and deporting those subject to federal immigration enforcement.”

“The Court will ‘adhere to the time-tested adage: if it walks like a duck, quacks like a duck, and looks like a duck, then it’s a duck,’” Williams said.

The facility, which gained its moniker from Florida Attorney General James Uthmeier (R), sits on a small airport in the Big Cypress National Preserve.

Williams said the preserve was created for conservation and preservation of the Everglades, and “this order does nothing more than uphold the basic requirements of legislation designed to fulfill those promises.”

“This ruling affirms what we argued in court — that the government can’t just build something in the middle of the Everglades and the Big Cypress preserve with no environmental review, and no public input,” Tania Galloni, managing attorney for the Florida office of Earthjustice, said in a statement.

The environmental groups that sued over the lack of environmental considerations identified a “myriad of risks” to the wetlands and endangered species—including the Florida panther and bonneted bat—from the facility’s runoff and wastewater discharge, the court said.

While DHS argued its expanded immigration enforcement necessitates the development of the facility, “they offered little to no evidence why this detention camp, in this particular location, is uniquely suited and critical to that mission,” Williams said.

The plaintiffs, which include the Friends of the Everglades and Center for Biological Diversity, sued the DHS and Florida agency in June, arguing the operation of an immigrant detention center was a federal action that warranted an environmental review under NEPA.

The court “recognizes the unique and unprecedented situation presented by this case” as well as “the interests of the Defendants and the importance of a well-ordered transition while Defendants modify the facility to perform the necessary environmental assessments,” Williams said.

The DHS didn’t immediately respond to a request for comment.

The groups are represented by Earthjustice, Coffey Burlington PL, and the Center for Biological Diversity.

The case is Friends of the Everglades v. Noem, S.D. Fla., No. 1:25-cv-22896, preliminary injunction 8/21/25.