At about 10:32 a.m. on the 1st, a fire broke out at SK hynix's Cheongju 4 Campus in Cheongju, North Chungcheong, releasing some fluorine harmful to the human body. The fire was extinguished immediately as the sprinklers activated. SK hynix said seven employees moved to the in-house hospital, but as of now there have been no casualties or production disruptions.
According to fire authorities and others, the fire started in a sixth-floor gas room connecting the M15 and M15X plants at SK hynix's Cheongju 4 Campus. The fluorine concentration measured at the scene was reported to be around 5 ppm.
About 10 people were reportedly working at the site at the time. Of them, five complained of eye irritation, and the other two showed no unusual symptoms but were within the area affected by the gas leak, so they moved to the company's affiliated hospital for a thorough examination.
An SK hynix official said, "Under internal procedures, we moved members who showed abnormal findings to the in-house hospital for treatment," adding, "There is no issue to note yet."
Right after the fire, SK hynix evacuated about 3,600 members from the M15 and M15X plants as a precaution. The company filed reports with relevant agencies while conducting firefighting measures in parallel and plans to identify the exact cause of the fire with the authorities.
At Cheongju 4 Campus, M15 is a production line focused on NAND flash. The expansion fab M15X is being developed as a base for next-generation DRAM production, including high bandwidth memory (HBM). An SK hynix official said, "There is no production disruption because there is no issue with equipment operation," adding, "Members will return once the safety inspection is completed."