At present, 80% of Russian gas exports to the EU flow through pipelines across Ukrainian soil, a source of ongoing tension.

BBC: Nord Stream gas pipeline opened by Merkel and Medvedev

Now, even though refined plans show an alternate route, environmentalists worry that if the expected 500, 000 to 700, 000 barrels of crude oil flow through the pipeline each day, leaks could contaminate the water and soil.

CNN: STORY HIGHLIGHTS