Aviation Security: TSA’s Change to Its Prohibited Items List Has Not Resulted in Any Reported Security Incidents, but the Impact of the Change on Screening Operations Is Inconclusive, GAO-07-623R, April 25, 2007: “The Transportation Security Administration (TSA) has primary responsibility for ensuring the security of civil aviation, which includes the safety of passengers and flight crew. One measure TSA uses to protect the aviation system is prohibiting individuals from carrying items that it determines to be a threat to the aircraft and its passengers into an airport sterile area or onboard an aircraft either in their carry-on bag or on their person. To implement this measure, TSA maintains a prohibited items list that informs both the Transportation Security Officers (TSO) who conduct passenger screening and the traveling public of items that will not be allowed into an airport sterile area or onboard an aircraft.”