OTSU, SHIGA PREF. – A civic group filed a criminal complaint with prosecutors and police Thursday against four individuals over their alleged involvement in dumping in Shiga Prefecture radioactive wood waste produced at a plant in Fukushima Prefecture.

Norio Ishida, a former professor of environmental toxicology at Kyoto University and one of the five members of the civic group, alleges that similar dumping has taken place in other parts of the country.

“It is our responsibility to keep radioactive materials from spreading. We filed the complaint as part of that effort,” he told a news conference.

According to the complaint, the head of a consulting company in Tokyo and three other individuals are alleged to have steered a company in Omihachiman, Shiga Prefecture, into dumping wood waste contaminated with radioactive cesium between last March and April.

The waste, consisting of wood chips produced at a lumber factory in the Fukushima city of Motomiya, was apparently dumped in a river and private property nearby in Takashima in northern Shiga without the consent of their owners.

Massive amounts of radioactive cesium and other contaminants were leaked from the Fukushima No. 1 nuclear power plant in Fukushima Prefecture after it was crippled by the powerful earthquake and tsunami that struck the Tohoku region in March 2011.