The US has agreed to carry out a joint investigation over whether it buried toxic chemicals, like Agent Orange, containing the highly toxic dioxin compound, in South Korea.
It is believed that the chemicals were illegally buried at an American army base in the 1970s.
The US military confirmed that its own records showed that it had dug up buried chemicals in Camp Carroll in 1979 and 1980, and that one of 13 soil samples taken in 2004 showed traces of dioxin.
Agent Orange has been blamed for causing cancer and serious birth defects in South Korea.
Al Jazeera's Harry Fawcett reports.