The US Navy is investigating a complaint that seeks the evacuation of civilian and military lawyers from parts of the US base in Guantanamo Bay, Cuba, following reports of cancer cases among personnel working on the trials of detainees there.

At least seven civilians and military members who worked on detainee trials at Guantanamo Bay have been diagnosed with cancer, according to the complaint, which was filed with the US Defense Department’s Office of the Inspector General. The complaint calls on American military officials to remove personnel from court facilities on the base and test them and the base itself for carcinogens.

The complaint claims that an unusually large number of relatively healthy and young people who worked at the base have been diagnosed with cancer. Over the past decade, roughly 200 prosecutors, defense lawyers and other court personnel have worked on the base.

The complaint says that the patients may have been exposed to carcinogens when they lived and worked in a location at Guantanamo that was formerly used to dispose of jet fuel, adjacent to an abandoned runway. The patients may also have been exposed to toxins such as asbestos in an older building that initially hosted military trials, according to the complaint.

“The Department of Defense is aware of concerns about possible carcinogens around the DOD military commission site located at Naval Station Guantanamo Bay,” said Kelly Wirfel, spokesperson for Naval Station Guantanamo Bay. “Working together with the Navy Marine Corps Public Health Center and other environmental and health officials, Navy Region Southeast is looking into this to identify whatever steps may be necessary to address these concerns.”

A spokesperson for the Defense Department Inspector General’s office said the office could not confirm or deny any investigations or complaints.

“We have been telling our chain-of-command for years that we don’t feel safe living and working in the temporary facilities the government has erected for military commissions,” said U.S. Air Force Capt. Michael Schwartz, a military defense lawyer who has worked on Guantanamo Bay for years. “But, along with the Constitution, the government seems to want to sweep this under the rug.”

The complaint doesn’t allege an increase in cancer levels among detainees, who are imprisoned on a separate part of the 45-square-mile base. There are currently about 115 detainees at the base, which President Barack Obama has been trying for years to shut.

If evidence of health risks does emerge at Guantanamo, it would add to a litany of problems that has slowed the trials. But the existence of a cancer cluster, which is what the complaint is essentially alleging, can be extremely hard to establish.

Two doctors consulted by Reuters said it would be difficult to determine whether the cancer rate at the base was abnormal without much more detailed information. They said seven cases would be unusual among a group of 200 younger people, particularly if all of them developed the same type of cancer. But seven people in a group of 200 developing different forms of cancer could be normal, particularly if the group’s members were older.

The author of the complaint worked on military trials at Guantanamo Bay for several years and is still employed by the U.S. military, according to another U.S. military official.

On Monday, Canadian media reported that U.S. Navy Lieutenant Commander Bill Kuebler, a longtime defense lawyer for Canadian detainee Omar Khadr, died of cancer on July 17^th. Kuebler was 44.

Civilian lawyers who have worked at the base said they supported the call for an investigation.

“There appears to be a cancer cluster surrounding the military commissions at Guantanamo,” said J. Wells Dixon, a lawyer with the Center for Constitutional Rights, who has represented dozens of Guantanamo detainees. “And the Centers for Disease Control should be brought in to investigate the matter thoroughly.”