The computer's voice repeatedly droned "Gamma Alert!" until Glen Neilson, a Customs and Border Protection officer, reached up and switched it off. It was his fifth radioactivity alert in five minutes.
Neilson was working at Pier A in the Port of Long Beach, which has more such alerts than any cargo terminal in the nation. A truck hauling a rusty yellow container triggered this one.
He directed the truck to a secondary inspection station and called up the container's shipping manifest. Something didn't look right. The cargo was supposed to be window shutters from China.
Neilson picked up a microphone and ordered over a loud speaker "pop the can," meaning officers would use a 4-foot bolt cutter to open the container. They brought out a hand-held isotope scanner to pinpoint the source of the radiation.
After 10 minutes, the mystery was solved. Once again, it was not a nuclear bomb being smuggled by terrorists. Instead, it was big-rig driver Francisco Villalpando of Gardena, having received a dose of medical radiation 10 days earlier, who was lighting up monitors from his driver's seat. "I've been setting off radiation alarms all over the port," he grumbled.
The system worked just the way it was designed that morning, but the incident also provided a glimpse into the difficulties customs agents have on the front line against nuclear smuggling.
Every day, about 500 radiation alarms sound at the Long Beach and Los Angeles ports, a nuisance that is growing as the federal government ratchets up the nation's defenses.
Over the past year, customs officers have begun scanning every container that enters the United States for traces of radioactivity.
Not satisfied with that, the Bush administration has embarked on a far-reaching technological effort to achieve a nearly leakproof barrier.
U.S. radiation monitoring equipment is running at eight foreign ports that send goods to the United States and at about 450 border crossings and airports around the world.
Under federal law, 100% of cargo arriving legally at U.S. borders by 2012 will be scanned abroad and then again at U.S. ports. More sophisticated monitors, costing billions of dollars, are under development.
Ultimately, federal officials envision a time when the nation will be ringed by radiation monitors at ports, along isolated sea coasts, plying the oceans, roving highways in police cars and even dotting checkpoints on routes into major cities -- all tied into a central national command center and staffed around the clock.
Some scientists at the Department of Homeland Security are calling the effort Manhattan 2, referring to the massive project that developed the first atomic bomb.
Vice President Dick Cheney has taken a special interest in the effort and backed the political appointment of a key ally to the job of developing the architecture for the system.
But nobody is sure that any system in the foreseeable future can keep out terrorist nuclear bombs with absolute assurance. Plutonium and highly enriched uranium, contrary to public perception, have very low levels of radioactivity. With a bit of lead or other shielding material, no existing detector can find them. Moreover, lots of normal cargo -- as innocuous as granite counter tops and ceramic vases -- puts out gamma radiation.
"People think we are going to catch a terrorist bomb with these radiation monitors," said Laura Holgate, a former Defense Department and Energy Department nuclear weapons expert now at the Nuclear Threat Initiative, a Washington advocacy group. "If we can't catch people and drugs coming across our border, I have no confidence that we can create a seamless security perimeter for nuclear weapons."
What's more, pressure to deploy more advanced monitors is quickly leading to alleged abuses.
The most recent flap involves the "advanced spectroscopic portal," a $1.2-billion effort by the Domestic Nuclear Detection Office, a part of Homeland Security. Production was stopped last month amid allegations by the Government Accountability Office that federal program managers rigged testing to certify that the equipment worked as advertised and reports that the machines were not reliable.
Rep. Bart Stupak (D-Mich.), who has held a series of hearings into the radiation monitoring program, is convinced that the new generation of monitors is no better than the old. "The next generation of equipment will only be as good as the next salesman knocking on the door of the Department of Homeland Security," Stupak said.
While the administration is rushing to make ports invulnerable, he said, little is being done to stop potential smugglers from walking across the Mexican or Canadian borders, or to plug other obvious weaknesses in the system. "The entire strategy is wrong," he said. "The advanced spectroscopic monitor is only one part of a much bigger problem."
