Regarding the two lines of NF₃ producing facility which has been out of operation due to the fire which occurred in Kanto Denka’s Shibukawa Plant on August 7, the company has clarified to the public the cause of the accident and announced that one unaffected line will restart operation from September 17. 

　As one employee of the company died and another got injured lightly in the fire accident, the company stopped operation of the NF₃ production facility in which the fire occurred, and at the same time has been investigating the cause. 

 According to the fourth investigation report announced on September 12, it was found out that in the boosting process after purification the internal gas (to be kept at a high pressure) entered by an irregular operation of the manual valve and the gas flown into the piping at a low temperature but high pressure caused an expansion of the gas. Ultimately it resulted to have caused a rapid flow of the combustible NF₃ inside the valve. It broke the piping explosively due to the burning of the plastic material of the valve.

  Based on the outcome of the investigation, the company decided to restart operation of the one line unaffected by the accident from September 17 now that avoiding measures have been taken. As for the lime which caused the breakout, the company will get ready to restart operation as soon as getting permission by the authorities concerned.