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Tokyo flights trigger radiation detectors

Airline passengers who triggered radiation detectors at U.S. airports added to the jitters about Japan’s nuclear crisis, but U.S. officials say there’s little risk.
/ Source: NBC News and

Airline passengers who triggered radiation detectors at U.S. airports added to the jitters about potential nuclear contamination from Japan.

But U.S. security officials emphasized that hazardous levels of radiation had not been detected and that the alarms were not unusual and could be caused by commonplace things.

"We get tens of thousands of readings of these kinds of levels every year," a U.S. official told NBC News.

Still, monitoring efforts were heightened Thursday for airline flights, ships, cargo, and mail coming into the U.S. from Japan, security officials said.

"In an exercise of caution and just to make sure that everyone remains safe, we are doing screening of passengers and cargo if there happens to be even a blip in terms of radiation," Homeland Security Secretary Janet Napolitano said Thursday.

Chicago Mayor Richard Daley said Thursday that passengers from one flight from Tokyo had triggered radiation detectors at O’Hare International Airport, The Chicago Tribune reported.

Daly said federal authorities were handling the situation, according to the newspaper.

"Of course the protection of the person coming off the plane is very important in regards to any radiation, especially within their families and anything else,” Daley said during a news conference, the Tribune reported.

But reported that five or six planes flying into O'Hare from Tokyo in the past 24 hours had tested positive for radiation in the jets' cargo areas.

Radiation detectors also were triggered at Dallas-Fort Worth Airport, the New York Post reported.

Homeland Security and Customs and Border Patrol agents were screening passengers, luggage and mail arriving on flights from Japan at various airports nationwide.

Some other countries, including Taiwan, were also scanning passengers arriving from Japan.

No new measures were deployed because the federal government already monitors incoming traffic for radiation, DHS officials said. But Customs and Border Protection Agents were told to give extra scrutiny to cargo and passengers arriving on flights that originated in Japan.

"CBP frontline personnel are equipped with personal radiation detectors that can detect the presence of radiological materials. And all airports have more sensitive radiation isotope identification devices to determine both the presence and type of radiation encountered," according to a statement from Customs and Border Protection.

So far, no hazardous radiation levels have been detected, officials said.

Those "blips" are routine. In fact, said a DHS official, more than half a million are detected every year. Low levels of radiation are emitted by medical equipment, ceramic tiles, and kitty litter made from clay. Even passengers who have recently undergone medical treatments involving radioactive isotopes emit enough radiation to trip the highly sensitive detection equipment, the official said.

NBC News correspondent Pete Williams and staff contributed to this report.