Relatively weak MFs could kill as an indirect result of the injury: http://mentalfloss.com/article/18405/mri-magnet-madness http://boards.straightdope.com/sdmb/showthread.php?t=544233

The effect depends on field signal characteristics (frequency, amplitude, wave shape), duration of exposure, genetics and metabolism. Some bacteria can be negatively affected even by 10 mT. In clinical trials people were "safely" exposed to up to 3 T.