The ArcelorMittal Krivoy Rog, Ukraine’s largest steel producer, halted production after repeated Russian attacks, the company announced on Friday, according to RT.

The mill was struck four times over five weeks, killing five workers, according to SBS, citing Reuters, and the company said safe and sustainable operations were no longer possible. With Zaporozhstal and Kamet Steel halted, the three plants that accounted for about 90% of Ukraine’s steel output are shut down, according to the Financial Times.