Radiation abnormalities surge among North defectors from nuclear test site: South data

North Korean defectors from the Punggye-ri nuclear test site are showing abnormalities but the South Korean government's follow-up care has been lagging over the years, according to data obtained by the JoongAng Ilbo.

Chromosomal abnormalities were found in 55 of the 174 North Korean defectors tested for radiation exposure over the past three years, according to the health data submitted by the Ministry of Unification and Korea Institute of Radiological & Medical Sciences to People Power Party Rep. Ahn Cheol-soo.

By each year, 17 cases were identified to have abnormalities of 80 people tested in 2023, 12 of 35 in 2024 and 26 of 59 in 2025. Last year, nearly half those tested showed abnormalities.

Despite the sharp increase in abnormal findings, the government’s effort to conduct comprehensive testing has made little progress.

In 2018, the Ministry of Unification announced plans to test all North Korean defectors from areas near the nuclear test site. But the checkup was suspended entirely for four years from 2019 through 2022 — under the Moon Jae-in administration. It resumed in 2023 under the Yoon Suk Yeol administration.

Of the 800 eligible defectors from areas near Punggye-ri, only 26 percent, or 214, underwent testing between 2023 and last year. That amounts to roughly one in four people targeted for screening.

Follow-up care has also been insufficient.  The radiological institute recommends that people with abnormal findings undergo a detailed examination once a year because the effects of radiation exposure can emerge years or even decades later.

Yet only 13 North Korean defectors received follow-up examinations over the past three years. Five were examined in 2023, nine in 2024 and five in 2025. The incumbent Lee Jae Myung administration has also set this year’s target for follow-up examinations at just 10 people, in line with the low numbers recorded in previous years.

It is also unclear whether the checkup program will continue.

“The ministry would decide whether to continue the program beyond 2026 after reviewing demand and the program’s results,” the ministry wrote in data submitted to the lawmaker.

Rep. Ahn accused the government of seeking to scale back radiation exposure testing, which is directly related to the defectors’ health.

“The Moon administration effectively neglected radiation exposure testing, and this administration is already considering whether to continue the program even though comprehensive testing has yet to be completed,” Ahn said. “It raises suspicions about whether the government is seeking to scale back radiation exposure testing that is directly tied to the health of North Korean defectors, even as it publicly champions North Korean human rights.”

Yet an official from the Unification Ministry said it is difficult to conclude that nuclear testing has caused the abnormalities. 

“Experts at the Korea Institute of Radiological & Medical Sciences have indicated that it is difficult to determine whether the chromosomal abnormalities identified through radiation exposure tests are due to the nuclear test or other contributing factors,” the ministry official said. “For example, some people have undergone multiple medical CT scans or X-rays, while others have a long history of smoking.”

The official also noted that follow-up check up is rather moderate. 

“The follow-up testing rate is not low,” the official said. “Five of the 17 people with abnormal findings in 2023 underwent follow-up testing, as did nine of the 12 in 2024. The ministry and other agencies contact North Korean defectors with abnormal findings by phone and text message to advise them to undergo follow-up testing. However, we received legal advice that they cannot be compelled to undergo testing if they do not wish to do so.”

BY RYU HYO-RIM [lee.soojung1@joongang.co.kr]