What do you think is the marine blue light shinning from the 2nd nuclear reactor plant at Fukushima Japan?

You can see the blue light on the web listed below. http://tagosakuga.blog79.fc2.com/blog-entry-50.html. Someone think that light may be Cherenkov light. Is it dangerous?
Update: Thank you Jerry! We can see the blue light only from the second reactor. And We can see no light anywhere at night at this plant. And the we found there is more than 1sv/h radiation near 2nd reactor today. I'm lving near Fukushima Japan. So I have to decide soon whether or not we should take refuge from Tokyo.
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