A U.S. nuclear-powered submarine leaked radiation for more than two years, releasing the bulk of the material in its home port of Guam and at Pearl Harbor, Japanese and U.S. officials said Thursday.
http://www.washingtontimes.com/news/2008/aug/08/us-nuclear-sub-leaked-radiation/#ixzz3K87c94Lx

But after reviewing records of the sub, the Navy told Japanese officials Thursday that the Houston had been leaking much longer, since June 2006, and had made port calls to Japanese bases at Sasebo, Yokosuka and Okinawa before the leak was discovered.