With the passage of ATSA in November 2001, TSA assumed from the Federal Aviation Administration (FAA) responsibility for securing the nation’s civil aviation system. In accordance with ATSA, TSA is responsible for the procurement, installation, and maintenance of explosive detection systems, including EDS and ETD, used to screen checked baggage for explosives (see figs. 1 and 2) at TSA-regulated airports. EDS machines identify suspicious items or anomalies in checked baggage that could indicate the presence of explosives or detonation devices. At airports with EDS, EDS machines are generally employed for primary screening of checked baggage while ETD machines are used for secondary screening to help resolve questions raised by EDS screening. At airports without EDS, ETD machines are used as the primary method for screening checked baggage. TSA deploys EDS machines in stand-alone and in-line configurations. In a stand-alone configuration, checked baggage is manually loaded and unloaded by screeners (see fig. 1). In contrast, an in-line configuration integrates EDS machines with a baggage handling system—a conveyor system that transports and sorts baggage from the ticket counter through the baggage screening system. (See fig. 3, which shows an in-line configuration with three EDS machines.) Generally, an in-line checked baggage inspection system employs three levels of screening (see fig. 4). EDS machines perform automated (Level 1) screening. If the EDS machine is unable to clear a bag, it sends an alarm to a screener who performs a secondary (Level 2) inspection known as On-Screen Resolution by reviewing an image of the contents of the bag via computer monitor. If the screener cannot resolve the alarm using on-screen resolution tools, the bag goes to the Checked Baggage Resolution Area (Level 3) where another screener will perform manual inspection of the bag assisted by an ETD machine. TSA officials stated that deployment of an integrated, centralized in-line system of EDS machines can enhance security, increase screening efficiencies, and lower screening costs by, among other things, reducing the number of screeners needed to conduct baggage screening and reducing work-related injuries caused by lifting heavy bags. Installing an in-line system can require modification of an airport terminal, including removal of the existing system, installation of a new baggage handling system and EDS machines, and the use of an interim solution to screen checked baggage while the in-line system is built. TSA estimates that depending on the size and complexity of an in-line project, installing an in- line system can take one to four years at larger (category X and I) airports. In 2005, we reported that although TSA made substantial progress in installing EDS machines, the agency had not conducted a systematic, prospective analysis to determine which airports could achieve long-term savings and improve efficiencies and security by installing in-line systems or, where in-line systems may not be economically justifiable, by making greater use of stand-alone EDS rather than relying on the labor-intensive and less efficient ETD screening processes. We recommended that TSA systematically evaluate baggage screening needs at airports, including identifying and prioritizing the airports where the benefits—such as cost savings of screening operations and improved security—of replacing stand-alone baggage screening machines with in-line systems are likely to exceed the costs of the systems. TSA concurred and in response released its Strategic Planning Framework in February 2006, which identified and prioritized airports based on an analysis of several factors, including security risk and the amount of estimated cost savings. In March 2011, we reported that by continuing to replace or modify older baggage screening systems with more efficient solutions, including in-line screening systems, TSA could continue to eliminate baggage screener TSA agreed that the deployment of more efficient systems positions. offers potential personnel cost savings to the federal government. GAO-11-318SP. airports, will be operated at the levels in established requirements and we recommended that TSA develop a reliable schedule for the EBSP. DHS concurred with these recommendations and has initiated actions to implement them. In February 2012, we reported that we continue to believe that TSA might achieve savings in screening personnel costs by continuing to replace or modify older checked baggage screening systems with more efficient solutions, including in-line screening systems, to the extent possible. TSA reported that since the issuance of GAO’s 2011 report, it had replaced 60 stand-alone checked baggage screening machines with more efficient in-line screening systems. Since fiscal year 2006, about $6.8 billion has been made available to TSA for activities related to checked baggage screening (see table 1), making the EBSP one of DHS’s largest acquisition programs. Following the terrorist attacks of September 11, 2001, and the enactment of ATSA, airports relied upon various sources of funding to support security-related capital improvement projects. For example, as enacted, ATSA authorized the use of Airport Improvement Program (AIP) funds for projects to support the installation of explosive detection systems. Subsequently enacted statutes, such as the Vision 100—Century of Aviation Reauthorization Act (Vision 100), however, either limited or precluded the use of AIP to fund projects related to the installation of in- line systems. TSA, which is solely responsible for procuring and deploying equipment to screen checked baggage for explosives, also provides funding in support of related facility modifications. The Consolidated Appropriations Resolution, 2003, first authorized the use of LOIs by TSA for airport facility modification projects related to the installation of in-line baggage screening systems. Although not a binding commitment of federal funding, LOIs are agreements providing that TSA will reimburse airports or airlines for a specified percentage of an eligible project’s cost, subject to the availability of appropriations. This in turn enables an airport to proceed with a project because the airport and any investors are aware that the agreed-upon percentage of allowable costs will likely be reimbursed. The airport or airline is responsible for its share of the total funding needed to complete the project and generally must be capable of funding the project in its entirety. From fiscal years 2003 through 2007, TSA entered into 8 LOI agreements covering 9 airports. Pursuant to the law then in effect, these LOI agreements provided for a 75 percent federal cost share of allowable project costs. Beginning in fiscal year 2008 and in accordance with Vision 100, any LOI entered into by TSA was to reflect a 90 percent federal cost share. Since 2008, TSA has entered into 4 more LOIs at a 90 percent federal cost share. As of December 13, 2011, TSA reported that its net cumulative obligations for all 12 LOIs were $1.46 billion. TSA also uses OTAs to support airport facility modification projects related to the installation of checked baggage screening equipment. TSA describes OTAs, which have become the primary administrative vehicles through which TSA financially supports such projects, generally as single-year reimbursable agreements (in contrast to the multiyear LOI agreements). According to TSA, OTAs take many forms and are generally not required to comply with federal laws and regulations that apply to contracts or cooperative agreements, such as the Federal Acquisitions Regulations, thus enabling the parties to negotiate provisions that are mutually agreeable. According to TSA, the federal cost share applied to OTAs may be negotiated, but since fiscal year 2008 TSA has generally followed the federal cost share applicable to LOIs. As of the end of fiscal year 2011, TSA had used at least 150 OTAs to support airport facility modifications related to the installation of in-line systems. According to TSA, these OTAs have reflected federal cost shares ranging from 50 to100 percent. As of December 13, 2011, TSA reported that its net cumulative obligations for all OTAs were $1.74 billion. TSA reports that 337 of 446 airports (76 percent) the agency regulates for security have optimal baggage screening systems. The remaining 109 of 446 airports (24 percent) do not yet have optimal baggage screening systems in all screening areas. To be considered an airport with an optimal baggage screening system, as TSA considers it and as we define it for purposes of this report, an airport must have completed installation and activation of the in-line or stand-alone systems that best fits the airport’s screening needs without relying on temporary stand-alone systems.may have a mix of explosive detection systems (EDS or ETD) and configurations (in-line or stand-alone systems), depending on the airport’s needs. TSA officials told us that they plan to deploy equipment for an additional 201 in-line systems in the future, which will include the Thus, an airport with an optimal baggage screening system purchase of an estimated 685 new EDS machines for installation at airports that are not screening with optimal configurations. TSA aims to complete its efforts to deploy optimal screening systems by using EDS machines as the primary means for screening checked baggage at all category X, I, II, and III airports while continuing to use ETD machines as the primary means at category IV airports. Additionally, TSA plans to deploy EDS machines in in-line configurations at all category X and I airports and in-line or stand-alone configurations at category II and III airports. At each of the 10 airports we visited, we observed distinct checked baggage screening needs, based on an airport’s terminal configuration and the number of passenger boardings. We discussed an airport’s willingness and financial ability to pay for facility modifications required to install in-line systems. For each of these airports, officials and engineers provided documentation (for example, drawings and blueprints) on distinct facility modification projects to accommodate baggage screening system upgrades. According to airport officials, TSA and airport officials work together to determine the most appropriate baggage screening configuration based on an airport’s needs.