Most of the 6 billion pounds of cargo shipped on passenger airlines every year is commercial cargo, not checked baggage, and most of those crates and cartons are never scanned, exposing passengers to risk, according to U.S. Representative Edward Markey, a Massachusetts Democrat.
The problem is even greater on commercial shipping venues, with unscanned cargo rolling into the U.S. every year aboard 11.2 million trucks, 2.2 million rail cars and 51,000 cargo ships, according to the DHS.
The U.S. Transportation Security Administration, which operates airport security systems, says it faces a dilemma of choosing between inexpensive but inaccurate machines and expensive, high-quality machines.
Airport workers now scan baggage with two types of systems. Explosive trace detection machines are affordable -- they're the size of a laser printer and cost a few thousand dollars -- but rely on slow and error-prone human workers to collect test samples.
In contrast, explosive detection system machines can process up to 500 bags per hour but weigh as much as 17,000 pounds and cost up to $1 million. And airports must invest much more money to insert those machines into their existing baggage conveyor belts to speed the process.
Still, officials with the Bush administration insist they've made significant progress in fighting terrorism over the last five years. A "network" of law enforcement and intelligence agencies, improved terrorist databases and international cooperation have successfully thwarted multiple terrorist plots, U.S. Attorney General Alberto Gonzales said in a speech Thursday.
"If there is one thing that all Americans will be thinking and saying when we mark a terrible anniversary on Monday, it will be the simple phrase, 'never again,'" he said. "And the goal of 'never again' cannot be achieved by the federal government alone, by any state government alone, or by any local police force alone. Our network of prevention is instead the key to protecting the American people."