A government shutdown may disrupt the revocation of security clearances for those with dangerous mental illness, including the mechanism which could have prevented shooter Aaron Alexis from entering the Navy Yard in Washington, D.C., this September.

The Pentagon's Central Adjudication Facility decides whether individuals are granted or denied security clearances, and is staffed largely by civilian employees vulnerable to furloughs if the government fails to pass a spending bill by midnight Monday. CAF is also responsible for revoking security clearances under certain circumstances, such as mental illness or following a criminal incidents.

Bradley Moss, a D.C.-based lawyer specializing in national security law and security clearances, told the Washington Examiner he worries that warnings routed to CAF will not be properly addressed during a government shutdown.

"When you're understaffed, things get missed," he warned. "If offices like ... CAF are receiving warnings about the mental health status of other clearance holders, that information might not get timely addressed in the event of a shutdown."

Rhode Island police reportedly encountered the alleged Navy Yard shooter, Aaron Alexis, in August -- the month before he shot to death 12 people at the Navy Yard. Alexis said he was hearing voices, which the police reported to Newport Naval Station authorities. This should have been forwarded to CAF, which could have made a determination about whether to revoke Alexis' clearance. But ABC News reported that the information never made its way up the military's chain of command.

"A report similar to what the Rhode Island police provided to the local Naval command could get lost on someone’s desk and get overlooked for a period of time even after the government fully staffed back up," Moss said.

The Pentagon could not provide specific details regarding their plans for the Central Adjudicative Facility in the event of a government shutdown.

Navy Cmdr. Amy Derrick-Frost said that the Defense Department had "developed contingency plans in the event the government shutdown occurs. DoD will continue supporting various defense activities, though some may be more limited than others."

The shutdown could also affect those being considered for security clearance and those seeking an appeal of a clearance denial.