According to this GAO Report, TSA has not yet met the 100 percent screening mandate as it applies to inbound air cargo due to several persistent challenges. For example, about one-third of air carriers that commented on TSA’s proposal to screen all inbound cargo by the end of calendar year 2011 expressed concerns about being able to meet this date without causing significant disruptions in the air cargo supply chain. In response to these concerns, TSA proposed a new date of December 2012. TSA officials also said that it is difficult to verify the accuracy of the self-reported screening data provided by passenger air carriers used to determine the extent to which screening has been conducted in foreign countries. Further, there is no requirement for all-cargo carriers to report data comparable to passenger air carrier screening data, even though most inbound cargo is shipped into the United States by all-cargo carriers. TSA has not yet weighed the costs and benefits of requiring all-cargo carriers to submit screening data, and by doing so, TSA could determine whether this additional data could enhance its efforts to identify potential risks for inbound air cargo, develop cost effective strategies and measures to manage these risks, and provide additional assurance that all-cargo carriers are complying with TSA’s enhanced screening requirements.