It's for government to regulate what the boss chooses to do. "One death" is not a useful metric. The issue is the extent of risk, or some kind of probability. Thus a production plan that rested $1 million of profit on the death of a specific worker is really a type of premeditated murder, as you would agree. Alternatively, one that was premised on a fatality rate of x% is a different story. Obviously there is some level of x which would be automatically unacceptable. Let me turn the question around: suppose a life-saving drug entailed a production process with a certain worker death rate of .000000001%? If you feel obliged to accept this, as common sense would dictate, then you're a little bit pregnant.
We routinely acquiese in, or make collective decisions that entail fatalities. For instance, we permit people to own cars, knowing that tens of thousands will die in them, or in front of them. We can choose to allow an industrial process that results in a product that saves lives, notwithstanding that the process itself could take lives.
None of these problems go away under socialism, even of the ideal variety. You can imagine a perfect economic system, but modern industrial production will always entail degrees of risk, I would imagine. Otherwise you're into Luddism, or Louisism. You can't ask capitalism to be pristine without grappling with the implications for any realistic alternative that you envision. Obviously in the here-and-now there is room to tighten up regulation for the sake of occupational health and safety. All this blather about murder-by-capitalism fogs up the debate more than anything else. Gross cases of negligence (where X is high), much less criminal negligence (where X is over some legal limit), are still different from, and short of capital murder as presently defined.
mbs