Correct. The lead in the food cans wouldn’t likely have been nearly enough of a problem. The food cans were likely the source of the botulism that plagued the crew irrespective of the boilers.
The open question is whether the lead from the boilers was above and beyond typical lead poisoning of the general population at the time.
I have been trying to plot my future and your comments on searching for cities that will not big greatly impacted via climate change is VERY HIGH on my list.