Temporary liquid ban will aid flight safety

THE ISSUE British and U.S. authorities have thwarted a scheme of suicide bombings of airplanes bound from England to America.

COUNTERTERRORISM officials have known about the tactic of using liquid explosives since an al-Qaida scheme was exposed in the Philippines more than a decade ago. The Transportation Security Administration has imposed a temporary ban on passengers carrying liquids aboard commercial airplanes, and it should not be lifted until passengers can be protected from such a scheme.

Yesterday's arrest of two dozen people in Britain in connection with a plot to blow up nine airplanes heading from London to the United States prevented what police called "mass murder on an unimaginable scale." British officials immediately banned all carry-on luggage at London's Heathrow Airport, and passengers at all U.S. airports were forbidden to bring liquids onto planes.

The plot was reminiscent of a 1995 scheme by Khalid Sheikh Mohammed, the mastermind of Sept. 11, 2001, and his nephew Ramzi Yousef to use liquid explosives to explode a dozen airliners headed from Manila to Seoul and Hong Kong and then to U.S. cities, including Honolulu. It was foiled in early 1995 when Philippine authorities discovered Yousef's bomb-making operation in Manila.

Terrorists could assemble an explosive liquid from innocuous components brought aboard a plane in separate containers. The suicide bombers in Britain planned to use a peroxide-based solution that could ignite when sparked by a camera flash or other electronic device, according to a U.S. intelligence official.

The government might begin testing next week a new computer program with software that sounds an alarm when the density of pixels shown on a substance's X-ray image is characteristic of an explosive. Other technology being developed is aimed at scanning a bottle to determine whether it contains what is claimed -- shampoo, suntan lotion, wine and so on.

Until an effective method is found, passengers will have to endure the inconvenience of excluding all liquids from their carry-on baggage.