Ingredients for a Bomb Are Not Hard to Find

"When you bring them together, you have the most common commercial explosive," said Jimmie C. Oxley, an explosives expert at the University of Rhode Island.

Whatever might be attempted, current airport security measures would easily miss such substances.

"They don't have the ability to detect liquid explosives generally," said Alfred Blumstein of Carnegie Mellon University in Pittsburgh.

In 2003, the Department of Homeland Security shifted $61 million of its $110 million research budget to meet operational needs, such as to pay for passenger screeners, delaying the development of a device for detecting liquid explosives and other things, the Government Accountability Office reported in February 2005.

Members of Congress also say that the department's focus on improving nuclear detection technology has disrupted efforts to integrate government-wide research on a range of biological, chemical and explosives threats.

Deputy Secretary Michael P. Jackson acknowledged that DHS research budgets have "fluctuated over the years" and that refocusing research priorities on short- and medium-term projects is "among our core priorities." But, he added, developing "detection tools of all types" for explosives of all types is a top goal.

"We are doing some testing of machines that test liquids," Jackson said. "There's nothing that's currently suitable for mass deployment, but there are some promising technologies that we're looking at."

Staff writers Spencer S. Hsu, Karen DeYoung and Dan Eggen contributed to this report.