It started with one Airman, one routine inspection, and one smear of residue that should not have been there. Weeks later, the U.S. Air Force has yanked an entire family of test equipment out of its nuclear missile force — because the gear that keeps intercontinental ballistic missiles talking may also have been quietly exposing the people who maintain them to a likely carcinogen.

The device is the AN/PRM-10 test oscillator set, a signal generator used to check the communications systems of the Minuteman III. In August, an Airman at F.E. Warren Air Force Base in Wyoming spotted polychlorinated biphenyl — PCB — residue on one of the units during a routine inspection, reported it, and was given medical attention before returning to duty.

Six of eight

Air Force Global Strike Command laid out the sequence in an Aug. 28 statement. Once tests confirmed PCBs on that first unit, the 20th Air Force — which oversees the ICBM bases — ordered every AN/PRM-10 kit inspected. The review was done in three days. Potential PCB residue turned up on six of the eight systems checked.

All of them have now been pulled, and crews are switching to a modern replacement tester that is free of PCBs. The command says it is working with the Minuteman III program office to dispose of the old kits and to hunt for any other legacy gear that might be contaminated.

Why PCBs matter

PCBs were a workhorse chemical for roughly half a century, prized in electrical and heat-transfer equipment for their insulating properties and high boiling point — until the United States banned them in 1979 as evidence mounted that they were toxic. The EPA classifies them as a probable human carcinogen, with additional effects on the immune, reproductive, developmental and neurological systems.

The problem is that the Minuteman III entered service in the 1970s and still leans on components from that era. Where the missiles go, decades-old support equipment often goes too.

A bigger picture

Concern about cancer in the missile community has been building for years. In 2023 the Air Force launched the Missile Community Cancer Study after reports of non-Hodgkin’s lymphoma clusters at ICBM bases; sampling later found elevated PCB levels at Minot and Malmstrom and trace amounts at F.E. Warren. Advocacy group the Torchlight Initiative called the swift removal of the testers “a great start” while pressing for far more.

The reassuring version of this story is that the system worked: an Airman knew the hazard, spoke up, and the command reacted in days. The uncomfortable version is the one Reeves points to — that a single contaminated tester may be one visible edge of a much larger legacy problem the force is only starting to map. Either way, the message to the people who stand nuclear alert is overdue: the gear is supposed to protect the mission, not the other way around.

Sources: Air & Space Forces Magazine (Stephen Losey); Air Force Global Strike Command statement, 28 Aug 2026; U.S. EPA.