John Turner/U.S. Air ForceIt is a little-known mission within the United States Air Force that operates almost entirely underground, shrouded in secrecy – and is critical to national security.Those tasked with the job are known as missileers. Their work requires them to be on alert 24/7, and they are responsible for the maintenance, security and operation of the United States’ arsenal of Minuteman III nuclear intercontinental ballistic missiles. Their mission is one component of the U.S. nuclear "triad," which includes land, air and sea-based nuclear weapons.The weapons are monitored by the missileers who operate in what are known as "launch control centers," or LCCs, attached to three Air Force bases: F.E. Warren in Wyoming, Malmstrom in Montana and Minot in North Dakota. LCCs are essentially trailer-sized capsules positioned far beneath the earth’s surface, protected from threats and surveillance.Now, a mysterious threat has potentially emerged, which has prompted investigations by the Air Force and Department of Defense. These latest investigations were launched after reports emerged of cancer among dozens of former missileers, who believe there is a potential link between their cancer diagnoses and their time spent working inside the LCCs.Searching for possible connectionsRetired Lt. Col. Jason Boswell was a missileer assigned to Malmstrom Air Force Base between 2006 and 2007. Eight years later, he was diagnosed with non-Hodgkin lymphoma. Boswell's discharge papers state that his cancer was considered a presumptive condition based on his time serving at Al Udeid Air Base in Qatar.But after joining the Wounded Warrior Project as a mentor to others, he was paired with a fellow missileer he knew from Malmstrom, Lt. Col. Daniel Sebeck, who was also suffering from non-Hodgkin lymphoma. Boswell told ABC News that he and Sebeck quickly began searching for other cancer diagnoses within the missileer community.Boswell said they found through talking with friends that several other former missileers also said they had non-Hodgkin lymphoma. He says they immediately thought to themselves, "This is not insignificant, and we need to start voicing this and get people to listen."Sebeck began digging deeper.According to a presentation he gave to his superiors in 2023, which ABC News has reviewed, in all, he initially documented nine cases of non-Hodgkin lymphoma among hundreds of missileers he said he researched who had served in a 10-year span that overlapped Boswell and his service years. The median age of diagnosis was 42, according to Sebeck's findings.More than half of people are 65 or older when they are first diagnosed, according to the American Cancer Society.The latest Air Force studyIn 2001, the Air Force conducted a study looking into similar claims of a possible cancer link to work exposure among missileers serving at Malmstrom.The findings, which were released in 2005, concluded Malmstrom was "environmentally safe." Sebeck's presentation, along with pressure from Montana Sen. Jon Tester, led the commander of the Air Force Global Strike Command, Gen. Thomas A. Bussiere, to commission another medical study, called the "Missile Community Cancer Study."The commander ordered U.S. Air Force Medical Service researchers to undertake a comprehensive look at all aspects of missileers’ work, to include epidemiological and environmental surveys."Our leaders do not have to be a cancer survivor, like me, or be a parent of a child currently serving, like me, to take this issue incredibly seriously. That certainly helps with my motivation, but I want the leaders in the field to treat our people like they are their own son or daughter," Bussiere said in a statement.Sebeck’s findings also prompted a group of fellow missileers to start the Torchlight Initiative, which is asking those in the missileer community to self-report their cancer diagnoses. To date, they say they have received reports of 56 cases of various types of non-Hodgkin lymphoma, with nearly a third of them involving former missileers from Malmstrom.A possible carcinogen is foundThe Air Force told ABC News its study is ongoing and "finding a causation is difficult." But one year in, the Air Force says its study so far has led to the discovery of polychlorinated biphenols, or PCBs, on some surfaces within launch control centers at all three bases – Malmstrom, Minot and Warren.Two samples at Malmstrom and two at Minot were found above the EPA limit, prompting cleanups within those LCCs.“All sites were immediately closed for safety and a multidisciplinary team of experts was gathered to include medical, EPA, engineers, etc., to develop and institute cleanup and mitigation procedures and retesting. Mitigation efforts continue to ensure we keep our airmen and guardians safe," the Air Force said in a statement.The EPA lists PCBs as a "probable carcinogen," although a direct link between PCBs and non-Hodgkin lymphoma has not been established. In the 1970s, the U.S. banned the production of PCBs, which were widely used in electronics manufacturing at the time.The Department of Defense has expanded the study to now include investigating 14 additional types of cancer.Is there a cancer link to missileer work exposure?Cancer is the second leading cause of death in the United States, with more than 2 million people expected to be diagnosed this year, according to the American Cancer Society.Still, Dr. William Dahut, ACS's chief scientific officer, said it's hard to know if any two people's cancers are connected, and proving an official cancer cluster with non-Hodgkin lymphoma is even more difficult because of the complexity of the disease.“Non-Hodgkin's Lymphoma is not really one disease. It's a combination of diseases which can manifest in similar ways, but actually are very different biologically. Some you can live with for years without actually needing treatment,” Dahut said.He continued, “Oftentimes the cancers in the cluster are not as closely related biologically as it's seen at first blush.”Air Force leaders in a recent virtual town hall said in addition to the ongoing environmental survey, the first of five epidemiological review phases has been completed. They said they have not found an increased rate of non-Hodgkin lymphoma in this initial batch of data.However, the Air Force said there is data that “appears to show trends suggesting a potential increased incidence for breast and prostate cancer in the missile community,” while emphasizing that, “That picture will not be complete until we complete all phases of this Epidemiology Review.”The results of the study aren't expected until the summer at the earliest, officials said. Some missileers and their families who spoke with ABC News said they continue to hope those results will give them the answers they have been hoping for.The loss of a missileerJenny Holmes' late husband Mark was a second-generation Air Force missileer. She tells ABC News of the grueling shifts, called "alerts," her husband and his fellow missileers were required to work in the LCCs.“Before we were married, even before I was in Montana with him, he did, I believe, 36-hour alerts,” Holmes said. “That’s one shift.”“By the time we were married and he still had two and a half years left, they switched him to 24-hour alerts.”Mark’s father, a retired Air Force Lieutenant Colonel named Dan Holmes, was a missileer in the 1970s. “I said to Mark that I thought the missile operations career field was the best non-rated career field in the Air Force,” he told ABC News.But after hearing from Mark about how little had changed with the system and the then-grueling shifts that were required of him, something Dan hadn’t experienced, he says his opinion of the field has changed. “Had I known then what I know now, I would have told him, 'don't get anywhere near the missile business' because my experience 40 years ago had absolutely no relevance to what Mark would experience,” he said.But the worst experience was yet to come. In 2019, years