From the Federal Register

DHS is not
required to establish requirements, rules, or
procedures with respect to such access.
Providing notice to individuals with respect
to existence of records pertaining to them in
the system of records or otherwise setting up
procedures pursuant to which individuals
may access and view records pertaining to
themselves in the system would undermine
investigative efforts and reveal the identities
of witnesses, and potential witnesses, and
confidential informants.
Dated: December 14, 2010.

Read the whole bloody thing.