Just to add context: "unknown causes" was the leading cause of death for Korean citizens as well in 2023 and not just foreigners.<p>Half of deaths with "unknown causes" is dying from old age. Other factors include SID, etc.
A lot of SK's foreigner workforce are unskilled laborers from poorer countries. So one explanation could be work related but unspecified due to company reputation or that no one simply cares about poor foreign workers.