After the September 11, 2001 terrorist attacks, explosive detection systems have become a part of all US airports. These systems run on a host of technologies, many of them based on GC-MS. There are only three manufacturers certified by the FAA to provide these systems. The first is Thermo Detection (formerly Thermedics), which produces the EGIS, a GC-MS-based line of explosives detectors. The second is Barringer Technologies, which is now owned by Smith's Detection Systems. The third is Ion Track Instruments (part of General Electric Infrastructure Security Systems).