The South Korean Unification Ministry recently revealed that studies into the health of North Korean refugees from areas near the supposedly defunct Punggye-ri Nuclear Test Site found about 30 percent of them carry chromosomal mutations.
The Unification Ministry revealed the information to the South Korean National Assembly on Friday and published the results. The study in question is the fifth of its kind into North Korean defectors from the area surrounding Punggye-ri, according to the South Korean newswire service Yonhap, and appeared relatively consistent with the result of prior tests looking for evidence of radiation exposure. Experts indicated that, while the tests could not rule out that the individuals tested obtained the chromosomal mutation through other means of exposure than nuclear weapons testing — such as smoking or being subjected to a CT scan — the proximity to a major nuclear detonation site is a clear suspect in what could have caused the test results in question.
A chromosomal mutation is a form of genetic mutation in which an entire chromosome’s DNA sequence changes. Acquired mutations, those that a person is not born with, are widely considered the most common cause of cancers. However, the Unification Ministry reported that none of the test subjects were diagnosed with cancer.
The study whose results were shared last week took place last year and reportedly tested 59 North Korean refugees from Kilju County, Hwadae County, Kimchaek City, Myonggan County, Myongchon County, Orang County, Tanchon City, and Paegam County, all near the nuclear test site. Notably, all defected after the first known nuclear weapons test at the site, which is located on Mount Mantap, in 2006. Of the 59 test subjects, 26 showed signs of what was described as “stable chromosome aberration,” according to South Korea’s SBS. Six of those tested reportedly experienced chromosomal abnormalities within the past three to six months.
“This means that chromosome mutations may have occurred due to exposure through water, air, and other pathways to nuclides released by nuclear tests, such as iodine-131, cesium-137, strontium-90, and plutonium-239,” SBS shared.
Cumulatively — observing the results of all five tests on North Korean defectors, SBS noted that 29.9 percent, or 64 out of 214 people, tested positive for possessing chromosomal abnormalities consistent with radiation exposure. Reports indicate that, in addition to 2025, North Korean defectors from the monitored area were tested in 2017, 2018, 2023, and 2024. The pauses occurred during the presidencies of left-wing President Moon Jae-in and conservative President Yoon Suk-yeol.
A matter frustrating the research has been the total lack of access to the areas around the nuclear test site — the communist leadership of North Korea is formally in a state of war with South Korea and closely monitors and limits any foreign entry into its borders — and the small number of defectors in South Korea from the affected areas. According to Yonhap, only about 800 North Koreans from the area live in the South.
The few who have escaped have for years complained of extreme body pain, bizarre illnesses, watching their neighbors die mysteriously, and witnessing the birth of severely deformed infants in the aftermath of the first nuclear tests near them.
“So many people died we began calling it ‘ghost disease,’” a defector from Kilju, one of the counties being monitored outside the nuclear test site, told NBC News in 2017. “We thought we were dying because we were poor and we ate badly. Now we know it was the radiation.”
The woman fled in 2010 but described living with chronic pain. Another such defector described neighbors in the affected area once having given birth to a baby who was so deformed “it didn’t have any genitals,” so his or her parents killed the baby.
Notably, the Unification Ministry told NBC News at the time that the woman recalling the spread of “ghost disease” had not tested positive for any abnormalities, but scientists complained to the outlet that the near-total lack of access to the site or its population made documenting the potential contamination extremely difficult.
“I don’t think they’re lying,” Professor Suh Kune-yull of Seoul National University told NBC News at the time. “We have to take their word, but I don’t have much reliable information.”
Similarly, a defector whose identity was kept private out of concern for persecution told Radio Free Asia (RFA) in 2023 that she had experienced watching her young son and several of his friends die of a mystery illness doctors identified as “tuberculosis,” but had no apparent explanation.
“Kilju County has the highest number of gastric, pancreatic, liver, tuberculosis, and lung cancer patients nationwide,” she shared with RFA. “When cancer patients are diagnosed, they die within three months.”
North Korea has carried out six known nuclear tests, all believed to have taken place under Mount Mantap at Punggye-ri, in 2006, 2009, 2013, twice in 2016, and in 2017. In 2018, dictator Kim Jong-un claimed that he had agreed to shut down the site and hosted a spectacle in which he invited foreign journalists — for a $10,000 fee — to come witness a modest explosion at the site, allegedly its demolition.
That year, a study found that Mount Mantap had lost as much as two feet in height following the tests, evidence some hinted could mean that the site was simply no longer usable and thus allowed Kim to stage the “demolition.”