If the venting of gases from the overheated reactors was as harmless as the Japanese government has been reporting, it does not seem as though this would be physically possible:

Of the 100 people evacuated by bus, nine had been tested and one had been shown initially with a radiation count of 100,000cpm -- a level at which experts say a person needs to be decontaminated.

Nor would this announcement be necessary:

Public broadcaster NHK flashed instructions to evacuees to close doors and windows, switch off air-conditioning fans and place wet towels over the nose and mouth, as well as to cover up as much as possible.

Either
A: The gas venting is more dangerous than reported.
B: There has been a containment breach.

Either way, the Baghdad Bob style "there is no problem here" statements may be putting people in danger.