Fishermen in Fukushima Prefecture have decided to expand the fishing zone off the northeastern prefecture nearly six years after a nuclear crisis caused havoc in the region.

The Fukushima Prefectural Federation of Fisheries Co-operative Associations will next month narrow down the restricted zone to within a 10-km radius of the crippled Fukushima No. 1 nuclear plant from the current 20 km.

In January last year the federation proposed expanding the fishing area, citing a declining density of radioactive material in the sea following the completion in October 2015 of seawalls to prevent contaminated underground water entering the ocean from the plant.

But the plan was postponed amid concerns over contaminated debris, which has since been removed.

“We keep saying sea products from Fukushima are safe, based on the results of radioactive tests,” Tetsu Nozaki, chairman of the federation, told reporters after it held a meeting in the city of Iwaki on Tuesday.