A number of North Korean defectors, who stayed near North Korea’s nuclear test sites, displayed possible signals of radiation exposure in medical checkups, according to the Ministry of Unification, South Korea. However, it was difficult to confirm the fact as to whether this was a result of the nuclear tests which took place.

According to a report by Yonhap News Agency, the ministry conducted tests of a nuclear radiation leak and health checks on 30 North Korea refugees who lived in the Kilju County which is situated near the country’s Punggye-ri nuclear site.

North Korea performed six nuclear tests at the site which is situated in the nation’s northeastern province, the report stated.

Out of 114 refugees who defected from North Korea, the ministry chose the ones who showed hope in undergoing the tests. The refugees who were tested, all of them defected to South Korea before North Korea conducted its fourth nuclear test on Jan. 2016.

According to the ministry, the chromosome examinations displayed that four defectors might have been exposed to radiation. However, other factors such as smoking and age weren’t ruled out as the reasons for the result.

The ministry also said that there weren’t any meaningful results from urine and other tests which were conducted.

In line with the same subject, one of the four North Korean soldiers who defected to South Korea this year, was discovered to have antibodies to anthrax, a bacteria that can be used as a biological weapon, Tuesday.

A South Korean intelligence official reportedly said, “Anthrax antibodies have been found in the North Korean soldier who defected this year .”

According to reports, having anthrax antibodies lead to two possibilities. Either the soldier was immunized against the bacteria or he was exposed to it. Having the antibodies meant that the soldier was immune to the bacteria, which can be a dangerous prospect.

According to a report last week by Asahi, a Japanese newspaper, North Korea commenced testing intercontinental ballistic missiles (ICBM) by loading anthrax in them. It was also believed that North Korea had a chemical weapon accumulation of 2500 to 5000 tons and also possessed the ability to produce biological warfare mediums such as anthrax and smallpox.

The Yonhap News Agency report further stated that experts were worried about the fact that due to nuclear tests, radioactive elements might have leaked into the nearby places which can jeopardize the health of the residents living in those areas.

Exposure to radiation could also result in diseases like leukemia and other forms of cancer.

The ministry, however, accepted the fact that the medical tests do have certain limitations due to the small number of samples and scarce amount of information. Another aspect of the limitation was that it had been quite some time since the test subjects were exposed to the radiation.

The ministry also stated that it had plans to advise North Korea defectors to get health checkups on a regular basis. The ministry also said that it will conduct more radiation tests on refugees.