Vis-a-vis Ebby's mention (a couple of posts previously) of the labor performed by Chinese folks out west, and how it was NOT "slavery":

Some of the "paid" (actually, underpaid) labor that built America's infrastructure, and that was assigned to various immigrant groups, was in a very real sense WORSE than slavery. It was so dangerous that economics dictated that human property not be risked by the employment of slaves.

The use of Chinese laborers ("coolies") in blasting rights-of-way through the western mountains for the transcontinental railroad is one good example. It's interesting to learn that these exploited workers were not even allowed to stay here if and when they survived upon completion of their work, but were deported back to China with their meagre earnings.

Another example of which I am especially aware was the use of Irish immigrants to dig the New Basin Canal in New Orleans back in the 1840s. The threat of disease (yellow fever and other tropical diseases) was so great that slaveowners refused to lease out their chattel to participate in the effort ~ their human property was too valuable to let them die in the effort to make civic improvements.

The first wave of famines in Ireland was just underway, and New Orleans quickly became the number-one US port of entry for Irish immigrants, because of the canal-digging jobs that were available. Once they arrived, however, so many died of disease that immigrants from Ireland to America forever after avoided New Orleans "like the plague." Statistically, an Irishman stood a better chance of survival by staying home and enduring the famine than by moving to New Orleans to dig the canal.

Ironically, native Louisianans (white and black, slave and free) would not have succumbed to the same diseases in any appreciable numbers. Current scientific opinion is that everyone who had survived childhood in the local environs had developed immunities to the various mosquito-borne diseases, while immigrants from elsewhere ~ not just from Ireland, but from anywhere in Europe and even from the northern US ~ were pretty much dead meat. Of course, no one at the time knew what we know today about disease, immunology,s.

The tendency of the immigrant groups (Italians and others as well as the Irish) to fall victim to these diseases in such great numbers became the basis of a widespread belief that the people themselves were dirty and unhealthy, a danger to "native Americans."