Norwegian scientists have discovered radiation levels 100,000 times higher than normal near a Soviet-era nuclear submarine that sank 30 years ago in the Arctic, Norway’s TV2 broadcaster reported Tuesday.

The Komsomolets sank in a section of the Barents Sea considered to be one of the world’s largest fishing areas in 1989, killing 42 of its 69 crew. Concerns about contamination from its nuclear reactor have not yet given way to an actual environmental crisis, and readings taken as recently as 2008 have shown no indication of a radiation leak.