The shooting occurred at about 3:45 a.m. at the station located on the 10000 block of Orr and Day Road.
Both the CHP and Whittier police are looking into the incident, which is being investigated as a suicide. No officers were involved in the shooting.
No one else was injured.
The man's identity was not immediately released, but authorities say he does not have any connections to the CHP or any other law enforcement agency.