From "ICE arrests 60 illegals working in sensitive areas":

U.S. Immigration and Customs Enforcement (ICE) agents have arrested 60 illegal aliens working as contract employees at a dozen critical infrastructure sites nationwide, including seven petrochemical refineries, three power plants, a national air cargo facility and a pipeline company.

There was no evidence that any of them had terrorist ties or were engaged in a terrorist plot, although they had access to sensitive critical infrastructure locations and posed a serious homeland security threat, said Department of Homeland Security Assistant Secretary Michael J. Garcia, who heads ICE...

The arrestees are from Mexico and Central America, and all of them worked for Brock Enterprises, which is reportedly cooperating with and isn't a target of the investigation.

The above is a Jerry Seper report; the AP report is similar except papers seem to have given it various interesting titles:

The Houston Chronicle's title manages to not be the longest and still be the clearest: "60 illegal immigrants arrested at plants in 6 states".

The S.F. Chronical stresses the arrestors and not the arrestees: "US immigration agents arrest 60 illegal workers across country".

An HR site gets PC: "60 Undocumented Workers Arrested".

And, the L.A. Times continues to lead the way with impartial, journalistically-excellent headline writing: "60 Immigrant Workers Held".

See the other posts in this category for many other examples of illegal aliens - even including gang members - working at secure facilities, including military bases.