WASHINGTON — Despite knowing for years that liquid explosives posed a threat to airline safety, security agencies have made little progress in deploying technology that could help defend against such attacks, security experts say. Since September 2001, the federal government has hired tens of thousands of government screeners and upgraded its metal detectors and X-ray machines. But most of the equipment is still oriented toward preventing a metallic gun or other easily identifiable weapon from being carried aboard; it cannot distinguish shampoo from an explosive. Cathleen A. Berrick, director of the Government Accountability Office’s homeland security and justice division, told a Senate committee in February 2005 that the Transportation Security Administration, part of the Department of Homeland Security, redirected more than half of the $110 million it had for research and development in 2003 to pay for personnel costs of screeners, delaying research in areas including detecting liquid explosives. It has continued to redirect some research and development money, she said Thursday. ‘They’d identified it as a vulnerability, they knew it was there, and they’d taken some steps to address it,” Ms. Berrick said. In 1995, a plot to bomb 12 American jumbo jets over the […]