In reply to the query about Irish and Black canal workers, it is
unfortunate that there are not good records of the number of casualties.  I
have been investigating this issue at the western end of the Erie Canal and
find that there were indeed Blacks as well as Irish and others involved.
One complication is that most of the work was contracted out, so records
are sketchy.  The NY State Archives has lists of workers and contracts--but
they are not easy to dig out, despite the helpfulnes of the staff.  For a
general picture of canal workers, check out Peter Way's "Common Labour."