I personally find it reprehensible that corporate heads are not held responsible for preventable accidents of this kind. If that is not criminal negligence, what is ? You can't tell me that they didn't know the dangers involved in operating substandard equipment. They knew and chose to ignore it, largely because their lives were not at risk and they knew they would face no punishment for their decisions.
Seven people dead in the pursuit of higher corporate profits and higher pay for those out of harms way.