WASHINGTON - Undercover investigators slipped a radioactive substance - enough, they say, to make two dirty bombs - across northern and southern U.S. borders last year in a test of security at American ports of entry.
Radiation detection equipment sounded at the unidentified sites, but the investigators were permitted to enter the United States after they displayed counterfeit documents that deceive customs agents.
A Government Accountability Office investigation, to be discussed at a Senate hearing Tuesday, said equipment used by U.S. Customs and Border Protection agents to screen people, vehicles and cargo for radioactive substances appeared to work when operated correctly.
But the investigation, carried out between July and December 2005 by Congress' investigative arm, also identified potential security holes that terrorists seeking to covertly carry nuclear weapons into the United States might be able to exploit.
"This operation demonstrated that the Nuclear Regulatory Commission is stuck in a pre-9/11 mind-set in a post-9/11 world and must modernize its procedures," Republican Sen. Norm Coleman said Monday in a statement. He referred to Sept. 11, 2001, the day of catastrophic terror attacks on the United States.
The commission, in charge of overseeing nuclear reactor and nuclear substance safety, challenged that notion.
"Security has been of prime importance for us on the materials front and the power plant front since 9/11," commission spokesman David McIntyre said in an interview.
He disputed the GAO's claim that the substance investigators carried was significant enough to have been to create two dirty bombs, which combine radioactive material with conventional weapons.
"It was basically the radioactive equivalent of what's in a smoke detector," McIntyre said.
A Senate Homeland Security subcommittee, which Coleman leads, released details of the investigation and two GAO reports on radiation detectors and port security before hearings on the issues this week.
The GAO also found that installing the radiation detectors is taking too long and costing more money than the United States expected. It said the Homeland Security Department's goal of installing 3,034 detectors by September 2009 across the United States - at border crossings, seaports, airports and mail facilities - was unlikely and said the government probably will spend $342 million (?284.4 million) more than it had expected.
Between October 2000 and October 2005, the GAO said, the government spent about $286 million (?237.8 million) installing radiation monitors inside the United States.
To test security at the United States' borders with Mexico and Canada, GAO investigators represented themselves as employees of a fake company. They presented counterfeit shipping papers and NRC documents that allegedly permitted them to receive, acquire, possess and transfer radioactive substances.
Investigators found that customs agents were unable to check whether a person caught with radioactive materials was permitted to have the materials under a government-issued license.
"Unless nuclear smugglers in possession of faked license documents raised suspicions in some other way, CBP officers could follow agency guidelines yet unwittingly allow them to enter the country with their illegal nuclear cargo," the report said. It described this problem as "a significant gap" in the nation's safety procedures.
McIntyre said the commission is working with the Homeland Security Department to ensure customs agents can verify that NRC documents are authentic. He said a national database should be ready late this year that will contain licenses of those who are permitted to have what the commission has determined to be the two most dangerous categories of radioactive substances.
False radiation alarms are common, sometimes occurring more than 100 times a day, although the GAO said inspectors generally do a good job distinguishing nuisance alarms from actual ones. False alarms can be caused by ceramics, fertilizers, bananas and even patients who have recently undergone some types of medical procedures.