The fire broke out at Nippon Steel & Sumitomo Metal Corporation's Oita Works in western Japan on January 5th. It heavily damaged electrical equipment at the mainstay factory producing steel plates for ships and other uses. The firm says it doesn't know when it can restart production.

Its factories in Chiba and Aichi Prefectures have already increased their production of plates to address the situation. But it has become increasingly difficult to make up for the loss.

Nippon Steel & Sumitomo Metal has asked 2 other Japanese firms, JFE Steel and Kobe Steel, to produce plates on its behalf.

The firm has not commented on the quantity it has asked others to produce.

Its Oita Works shipped 2.4 million tons of steel plates last year, equivalent to one-fourth of all domestic production.