According to a guest from NBC who called in to the Stephanie Miller show, this has not been confirmed by that network:
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.
As for radiation making its way to the west coast of the United States, he is saying that "it's an increasing concern, especially Unit 3, chock full of plutonium oxide, tons.... at a micron level that could fit through any filtration device... the size of a virus."
Of course, Gunter is unabashedly anti-nuke. In 2008, he won the Jane Bagley Lehman Award from the Tides Foundation for outstanding achievements in "the fight against nuclear power. Good for him.
Happy St. Patrick's Day!