The fatal fire at Mitsubishi Chemical Corp.'s ethylene plant in Ibaraki Prefecture was caused by failure to take adequate safety measures, according to the prefectural government's accident investigation committee. Failure to shut off the main cock of a compressed air valve used to operate another valve is reported to havee caused the fire. The fire that killed four people, occurred in December, and was caused when coolant oil leaked from a valve and ignited during pipe maintenance.
The panel will compile its final report Wednesday at a meeting in Kamisu. It is for the prefectural panel to conclude that even if the valve was opened by mistake, the accident would not have happened if the employees had taken such safety measures as locking the handles and closing the main cock to keep the valve from moving.