The Japanese Environment Ministry has accused decontamination companies of illegally dumping radioactive waste into rivers near Fukushima's No. 1 nuclear plant.
The ministry has planned to summon senior officials from the contractors to the Fukushima Office for Environmental Restoration to answer questions on how they manage contaminated waste.
The ministry said that some of the contractors hired to decontaminate areas are suspected of illegally dumping tainted material in the coastal town of Naraha, the hard-hit village of Iitate, and even farther inland in the city of Tamura, the Japan Times reports.
A special law made due to the nuclear disaster bans illegal dumping of contaminated substances into the environment and makes it punishable by up to five years in prison or a fine of up to 10 million yuan.
The guidelines for decontamination work require contractors to store tainted substances at the decontamination site or at temporary storage sites, the report added.