The maximum level for a nuclear accident is 7 so it's now considered as bad as Chernobyl. Estimates of deaths from Chernobyl range from 10,000 to a few hundred thousand. Hopefully the human toll won't be as because the problem has evolved slowly.
It was previously rated a 5 on the 'glow in the dark' scale. Because this rating system is logarithmic scale as the Richter scale for earthquakes, the change in rating increases the factor of the damage by 100 times.