WASHINGTON -- Security officials scrambled yesterday to quell public concern over a government report that warned of possible "dry runs" for a terrorist attack that would target airports, including Baltimore's.
Officials played down the information in the report, which highlighted an incident at Baltimore-Washington International Thurgood Marshall Airport last year in which a couple's checked baggage contained a block of processed cheese and a charger for a DVD player, which might have substituted for bomb components.
State transportation police tracked down the owners of the luggage, who were waiting for a Southwest flight, and after interviewing them determined they were not a threat, said Cpl. Jonathan Green, a spokesman for the Maryland Transportation Authority Police.
"Every indication was that they were not a threat as passengers," he said, though he did not know whether they got on a plane after their luggage was returned to them.
There was no need to shut down a section of the airport to find the passengers, he said, which has happened at least twice before. Gov. Martin O'Malley said he was briefed yesterday on the incident at BWI and is confident it did not represent a risk.
"I'm heartened by the fact that [TSA's] increased screening of bags allows us to determine what could be dry runs," O'Malley said.
The Baltimore incident was similar to three others around the country over the past year, according to the report in the Transportation Intelligence Gazette, dated July 20, which the Transportation Security Administration issued to federal, state and local officials.
"The kinds of things in the bulletin are anomalies," said TSA spokeswoman Amy Kudwa, referring to the Baltimore incident and three others. "We are not overly alarmed."
She added that the report that went out is "not a threat bulletin. This is an information bulletin."
"We get those routinely," said Jonathan Dean, a spokesman for BWI. "These types of bulletins are not unusual when TSA has information to share."
He said BWI is "operating normally" and noted that every U.S. airport has been at an elevated or "orange" threat level since an alleged plot to attack U.S.-bound airplanes was uncovered in Britain last August.
Other recent security reports have covered such threats as an alleged plan to conduct chemical attacks on U.S. cities, potential threats to offshore oil platforms, and security vulnerabilities at Sky Harbor Airport in Phoenix, according to a counterterrorism official familiar with the matter.
"Its something they're concerned about, but I wouldn't say there are people running around with their hair on fire," said a federal law enforcement official who discussed the TSA report on condition of anonymity because he is not authorized to speak with the press.
Green, the Maryland transportation official, declined to comment on any state action taken in response to the July 20 report, which suggested that the incidents might represent preparations for an attack.
The report, which became public one week after the government warned of a heightened terror threat in the U.S. from al-Qaida, stood out because it was so specific and identified a trend observed over the past year, said John Rollins, a former top intelligence official at the Homeland Security department.
The materials found could mimic a bomb made of plastic explosives, suggesting that the passengers might be testing the screening system to see if they could get actual bomb components aboard a plane, said Van Romero, vice president for research at the New Mexico Institute of Mining and Technology, which specializes in explosives.
Cheese, as well as clay, has a consistency similar to plastic explosives such as C4 or Semtex. The electrical components listed in the bulletin would give off an electronic signal similar to a device that would trigger a bomb, he said.
"This is a very real concern," said Romero, who has also served on homeland security advisory panels. "If someone or a group of people can find a hole in the system -- a particular combination of materials that could easily go undetected, then obviously they'll try and exploit that."
The bulletin reported that airport security and law enforcement officials had intercepted "several items at airports resembling improvised explosive device (IED) components" and that "most passengers' explanations for carrying the suspicious items were questionable."
The Baltimore incident took place Sept. 16, 2006. The TSA report said a couple had packed the cheese and a cell phone charger in their checked luggage, but Green said the electronic item was actually a car-charger for a DVD player.
The other suspicious incident involving cheese took place in June, 2007, in Milwaukee, where a passenger's carry-on baggage contained a wire coil wrapped around a possible bomb initiator, an electrical switch, batteries, three tubes, and two blocks of cheese, according to the TSA report.