This is a contingency contract only, and Kellog Brown Root (a Haliburton subsidiary) was the only bidder.

A spokeswoman for Immigration and Customs Enforcement, Jamie Zuieback, said KBR would build the centers only in an emergency like the one when thousands of Cubans floated on rafts to the United States. She emphasized that the centers might never be built if such an emergency did not arise.

NY Times article