A lawmaker from the Democratic Unified Party, an opposition party of south Korea, revealed the fact on Tuesday.

A survey made of the contaminated soil around 13 bases last year indicated that the oil and chemical substance which contaminate 11 bases were far beyond the tolerance level.

Poisonous substance discovered in a base of Hwachon, south Korean Kangwon Province, in particular, was more than 20 times the tolerance limit and xylene more than 56. 3 times the tolerance limit was detected in another base.

Besides, it was reported that leakage of chemical substance including carcinogenic and toxic substance from many bases is creating the danger of contaminating even underground water.