JDC Corp., a midsize general contractor, discharged 340 tons of radioactive water into the Iizaki River, which is tapped for irrigation in Minamisoma, Fukushima Prefecture, during government-sponsored decontamination work it was involved in, company sources said Thursday.

Local government officials claimed they were never informed of the action. But JDC sources said the dumping occurred after it received assurances from the Japan Atomic Energy Agency, which contracted it to carry out the decontamination work, that the state body had informed the local governments about the discharge in advance and no problem was anticipated.

The company had not been aware that water from the river would be used for agricultural purposes, the sources added.