The title here is the title of an article in Salon reprinted in full in Spiegel Online.  This from the lede:

Halliburton and its subcontractors hired hundreds of undocumented Latino workers to clean up after Katrina -- only to mistreat them and throw them out without pay.

The link to that article, and a wealth of information on topic is available from Gulf Reconstruction Watch.

In their attempts to gather information the Salon reporters came across this gem:

(James) Hale says that his union's legislative staff has pressed members of Congress for more information; apparently the legislators were told that they could not get copies of the contracts because of "national security" concerns. [Hale is a VP of the Laborer's Union].

Note that all of the work described is being performed on U.S. military installations throughout the Southeast.  Lack of toilet paper and food an issue of national security?