sentences:  Scientists of the United States National Research Council have taken the position that it should be assumed that microbial life exists in Lake Vostok and that after such a long isolation, any life forms in the lake require strict protection from contamination.The original drilling technique employed by the Russians involved the use of Freon and kerosene to lubricate the borehole and prevent it from collapsing and freezing over; of these chemicals have been used thus far on the ice above Lake Vostok.Other countries, particularly the United States and Britain, have failed to persuade the Russians not to pierce to the lake until cleaner technologies such as hot-water drilling are available.