Unintentionally passing a disease that kills someone else

A person is sick, but still goes to work (ICU in hospital). He knows he is somewhat sick, but still goes to work without considering the potential harm he could be doing to the vulnerable ICU patients by going to work with that sickness. In the extreme case that someone or some people die from a sickness unintentionally passed on by this worker, is this worker considered a killer in Islam? Or would this be considered killing by accident? Would there be any expiation for this? Thanks for helping

Dear Brother / Sister,

He is not considered as a killer in respect of the penalty provisions, but he commits sin and becomes responsible.

Questions on Islam