The government's response to Typhoon Hagibis dominated Tuesday's debate in the Diet.
Opposition lawmakers grilled the government on its handling of the storm, including why radioactive waste produced after the 2011 nuclear disaster was not properly protected.
Multiple bags of waste produced from decontamination efforts flooded into a river in Fukushima.
Environment Minister Shinjiro Koizumi says local officials found 10 bags that had been swept away by the storm and are investigating whether there are any more.
Koizumi said, "I've received reports that large bags that have already been collected were not damaged, so there won't be any impact on the environment."
Another issue debated was the management of emergency shelters.
Opposition members pointed out that a municipality in Tokyo did not accept homeless people at some evacuation centers.
Yuko Mori of Democratic Party for the People said, "We should respect the basic human rights of disaster victims and provide necessary facilities for them. That's a basic principle."
Prime Minister Shinzo Abe replied, "I think it would be desirable for each evacuation center to properly accept all people. We will examine what really happened with the local governments and take appropriate measures."