Tens of thousands of North Koreans and people in South Korea, Japan and China could be exposed to radioactive materials spread through groundwater from an underground nuclear test site, a Seoul-based human rights group said in a report on Tuesday.
North Korea secretly conducted six tests of nuclear weapons at the Punggye-ri site in the mountainous North Hamgyong Province between 2006 and 2017, according to the U.S. and South Korean governments.
