Bacteria that cause a severe form of pneumonia were detected in the federal building in downtown Baltimore that houses controversial immigration holding rooms, according to a letter from members of Maryland’s congressional delegation.

On Friday morning, the group of Democratic lawmakers sent the letter to the Trump administration’s General Services Administration, raising concerns about a “Legionella bacteria outbreak” detected at the George H. Fallon Federal Building in November. The letter says the GSA, which oversees federal properties, conducted a baseline test that confirmed the presence of the bacteria, which can be deadly.

In response to the testing, the GSA used a hyperchlorination treatment, according to the letter, but the Maryland lawmakers have been told the bacteria are still present in the building’s water system.

The building’s tenants — including local offices of the U.S. departments of the Treasury, Veterans Affairs, Justice and Homeland Security — have received “varying levels of communication” about the status of the outbreak, the letter says, and some may remain unaware.

“We are particularly concerned by this development in light of reports of overcrowding at the Baltimore Immigration and Customs Enforcement Field Office’s holding rooms, as well as the presence of a child care facility, in the building,” the letter says.

The conditions in the holding rooms, first reported by The Banner last spring, have sparked regular protests outside its walls, outrage from members of Congress and a lawsuit designed to improve what have been described as inhumane conditions. A federal judge on Friday as part of a separate lawsuit ruled ICE must limit the number of detainees it holds at the facility, citing safety and health concerns.

On Friday afternoon, ICE said in a statement the agency “remains committed to always upholding the safety and well-being of all detainees in custody.”

GSA responded in its statement that the agency is “committed to ensuring the safety of federal employees, contractors, and visitors in our federal buildings.”

In addition to communicating regularly with its tenants, GSA said it has implemented an industry-standard drinking water management plan that includes checks on water flushing, temperature and residual disinfectant, along with periodic testing for Legionella, according to a statement.

The agency did not reveal the results of any recent testing or whether anyone had been sickened by the outbreak as alleged by the lawmakers.

Legionella bacteria can cause Legionnaires’ disease, which is a severe form of pneumonia, and Pontiac fever, a mild illness that can include fever, muscle aches and headaches, according to the Centers for Disease Control and Prevention.

The bacteria can occasionally cause infections outside the lungs, such as heart or wound infections, according to the CDC.

Legionnaires’ disease symptoms usually develop two to 14 days after exposure. Symptoms include cough, fever, headaches, muscle aches, shortness of breath, diarrhea, confusion and nausea.

“The presence of these bacteria, and the lack of clear direction from GSA, poses a serious health and safety threat for all users of the Fallon Building,” the letter reads.

The delegation asked the GSA to “undertake immediate remediation measures.” The group also asked the GSA to respond to a series of questions by March 20 about the apparent outbreak and the federal agency’s response.

The letter was signed by Sens. Chris Van Hollen and Angela Alsobrooks and Reps. Kweisi Mfume, Steny Hoyer, Jamie Raskin, Glenn Ivey, Sarah Elfreth, April McClain Delaney and Johnny Olszewski Jr.

Detainees at the Baltimore Field Office are provided bottled water at all times, ICE wrote in its statement.

“The continued fixation by the media to portray ICE processing centers in a negative light is both misleading and irresponsible,” the ICE statement said.

“These repeated efforts ignore the reality that ICE operates in accordance with established standards and protocols. These narratives not only distort the facts but also contribute to our officers facing” more assaults and threats against them, the agency wrote.

“Yet local elected officials will prevent ICE from completing, and moving into, the modern and state of the art facility in Elkridge Maryland; it’s such a hypocrisy.”

Requests for comment to the GSA were not immediately returned.

Downtown Baltimore has faced this problem before. In February 2025, three courthouses — the Baltimore City District Court on East Fayette Street and the Clarence M. Mitchell Jr. and Elijah E. Cummings courthouses on Calvert Street — tested positive for elevated levels of the dangerous bacteria in the water.

The three buildings were closed for two days in December 2024 for remediation efforts following positive tests for Legionella.

Banner reporter Daniel Zawodny contributed to this article.