Just raise the sensitivity thresholds on the radiation detectors.  "All is well."

http://www.chicagobreakingnews.com/news/local/chibrknews-tokyo-flight-triggers-ohare-radiation-detectors-20110317,0,4216493.story

Mayor Richard Daley acknowledged today passengers on a flight from Tokyo had set off radiation detectors at O’Hare International Airport, but he offered no details and said federal officials will be handling the situation.

“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 at a downtown news conference to discuss his trip to China this week.

City Aviation Commissioner Rosemarie Andolino would only say, “We are aware that occurred yesterday. We are working with Customs and Border Protection on this issue." She referred reporters to the Department of Homeland Security.