According to Japan Times, a containment vessel at the destroyed Fukushima No. 1 power plant has reached off-the-chart radiation levels.

The reading of 530 sieverts per hour represents the highest level of radiation the reactor site has seen since March 2011 almost six years ago.

To make it easier to understand, the 530 sieverts reading is high enough to prove fatal during even brief exposure. Based on data from the National Institute of Radiological Sciences, 4 sieverts would kill one in two people, and 1 seivert could lead to hair loss and infertility.

The Fukushima 1 Nuclear Power Plant suffered a series of meltdowns and explosions after Tsunami-triggered earthquakes crippled Japan’s coast. The cleanup is expected to take decades.