Senate Appropriations Chairman Robert Byrd (D-W.Va.) today criticized the Homeland Security Department for not spending enough money on installing technologically advanced equipment at airports to detect liquid and plastic explosives used by terrorists.

“Five-and-a-half years have passed since 9/11, and air passengers still walk through archaic security devices that can not detect plastics or liquid explosives,” Byrd said at a hearing of the Senate Appropriations subcommittee on Homeland Security. “Yet the president proposes to reduce spending for explosive detection and installation by 17 percent.”

The Bush administration is requesting $46.4 billion for the Homeland Security Department in fiscal 2008.

Last summer, officials in the United Kingdom released details of a alleged plot to blow up planes on trans-Atlantic flights by carrying the bomb components, including liquid explosive ingredients and detonating devices, disguised as beverages and electronic devices. Following the announcement, U.S. airports beefed up regulations on the amount and size of liquid containers that passengers can carry though security and raised the national threat warning level to “high.”

Byrd questioned why the threat level has now remained “high” for nearly seven months yet the president’s fiscal 2008 budget does not seek more spending for explosive detection equipment. He noted that there is a $1.1 billion backlog for installing baggage systems to screen for explosives at the nation’s 25 largest airports.

Homeland Security Secretary Michael Chertoff said at the hearing that Byrd’s assessment was “quite right,” but he added that current detection technology has severe limitations and could not “adequately” detect liquid and plastic explosives.

“Even as we continue to acquire existing technology, we have to make sure we do not over-invest in a technology that has seeds of its own obsolesce,” Chertoff said.

In lieu of purchasing existing explosive detection systems, Chertoff said, the department is spending more on developing new technologies.

In addition, Chertoff said, Homeland Security had beefed up the training for airport screeners at the “entry points” of the screening process, including behavioral analysis techniques designed to weed out suspected terrorists.

“A combination of better training, behavioral-trained screeners, plus research in additional technologies gives a more comprehensive strategy than simply putting all the money into an existing but not totally effective explosive screening set of equipment,” Chertoff said.