system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: why is the Fukushima nuclear plant still a threat?
gpt
A clearer answer: bad materials such as iodine 121, caesium 134 (among others) have leaked into the surrounding water (used to cool the reactor's sealed water) and that water is leaking into the ground and into the ocean. 

The reactors and the waste storage (where they keep the old nuclear fuel cool) are not melting down, will not melt into the water table, and are at 35 degrees (C) and are under control.  

This data is all verified by non-Japanese officials.