Nine military officers who had worked decades ago at a nuclear missile base in Montana have been diagnosed with blood cancer, and there are indications that it could be linked to their service, according to recently obtained military briefing slides. The officers were all assigned to Malmstrom Air Force Base and were missileers, who ride caged elevators deep underground into a small operations bunker encased in a thick wall of concrete and steel.

In a presentation delivered to a Space Force unit this month, U.S. Space Force Lt. Col. Daniel Sebeck said that “There are indications of a possible association between cancer and missile combat crew service at Malmstrom AFB.” The Air Force has acknowledged the issue and medical professionals are gathering data to understand more.

“Missileers have always been concerned about known hazards, such as exposure to chemicals, asbestos, polychlorinated biphenyls, lead and other hazardous material in the work environment,” Sebeck additionally commented when speaking on the January slides. “All missileers should be screened and tracked for the rest of their lives.”

President Joe Biden signed the PACT Act last year which greatly expanded the types of illnesses and toxic exposures that would be considered presumptive for service members or veterans. Should there be a connection between the blood cancer and service at Malmstrom AFB, then the veterans affected could be eligible for care and benefits under the PACT Act.