Immigrants held at "Alligator Alcatraz", a now-shuttered detention centre in Florida, were kept in small metal cages for hours, according to a report from the US Department of Homeland Security's watchdog.

The Office of the Inspector General (OIG) found that the use of the outdoor cages, about 18 sq ft (1.67 sq m), was "unprecedented among detention facilities" and dangerous.

Investigators concluded the centre also did not comply with a number of standards for hygiene, medical care, food, health and safety.

The BBC has contacted DHS's Immigration and Customs Enforcement (ICE) and Florida Governor Ron DeSantis for comment. DHS told the watchdog that state officials ran the facility.

In its response included in the investigation report, DHS officials said Florida - not the federal government - had authority over day-to-day operations at the facility.

The facility was established by the state of Florida through an executive order signed by DeSantis, but the federal government paid for operational costs.

In January, the OIG conducted a surprise inspection at the detention facility, which had become one of the most notorious immigration detention centres in the US. The OIG is an independent internal watchdog at DHS. The current inspector general was appointed by President Donald Trump during his first term.

In 2025, the detention facility was built over the course of eight days in the Everglades, a protected wetland known for its alligators. Trump once joked that immigrants held there would need to learn "how to run away" from the reptiles at the facility, which civil rights groups have decried as inhumane.

In June 2026, DeSantis said the facility would close as it was only meant to be temporary.

According to the OIG report, between July 2025 and January 2026, the facility kept 79 immigrants in the small metal enclosures, describing them as "calming areas" for people to "deescalate and have time alone". They were held there from periods ranging from minutes to nearly two hours, at least once as a disciplinary measure, OIG said.

"The use of such restrictive spaces is highly unconventional and does not align with standards for humane treatment," the report stated.

Detainees at the facility have previously told the BBC that they were denied necessary medication, regular showers, and other hygiene measures.

In their report, OIG inspectors said they found immigrants held at the facility had to use showers infested with small bugs and were only allowed to do so three times a week.

The facility did not provide them with sufficient living space, "creating cramped conditions for detainees who spent most of their time in their housing units", according to the report.

Immigrants at the centre also told OIG that they did not have access to clean drinking water and could not clean the plastic cups from which they drank.