With two fires breaking out within 10 days at the SK hynix Cheongju plant, attention is focusing on the cause of the accidents. The industry and beyond are zeroing in on the background of the repeated incidents, noting that both occurred during similar processes in the same plant's gas room.
According to the industry on the 16th, a fire broke out on the morning of the 12th in the M15X gas room at SK hynix's Cheongju 4th campus in North Chungcheong. Earlier on the 1st, a fire had also occurred in a gas room within the Cheongju 4th campus. Both accidents were reported to have occurred during processes handling fluorine and nitrogen.
At the time of the accident on the 12th, a fire broke out while six workers were mixing fluorine and nitrogen in a cabinet. The blaze was extinguished internally within about 10 minutes as the sprinkler system activated. In the process, one worker suffered burns, and employees who reported dizziness and other symptoms were transported to the in-house hospital. During the accident on the 1st, fluorine gas partially leaked along with the fire, prompting the emergency evacuation of more than 3,600 employees.
This accident is noteworthy in that it occurred after the company resumed work upon removing elements presumed to be the cause of the fire on the 1st. Although another fire occurred in the same process within 10 days, the exact cause has not yet been identified. Both incidents occurred during processes handling fluorine and nitrogen, but the industry sees a low likelihood that fluorine itself triggered the fire. For now, the weight is on technical causes such as issues in the gas mixing process or equipment abnormalities.
The latest accident brings to mind the past fire at the Wuxi plant in China. The 2013 Wuxi plant fire started in the scrubber equipment and raised concerns about disruptions to the global DRAM supply. At the time, SK hynix required a considerable period to normalize production and subsequently pursued large-scale safety investments and measures to prevent recurrence.
A commonality is that both accidents occurred not in the main process that directly produces wafers, but in utility areas supporting production, such as gas and exhaust facilities. However, while the Wuxi fire directly affected production line operations and led to a shock to the global supply chain, the latest Cheongju incident differs in that the blaze was contained early and the plant continues to operate normally without production disruptions.
Some also raise the possibility that the recent expansion of production and the burden of plant operation, driven by rising demand for artificial intelligence (AI) chips, may have affected the safety management system.
However, voices in the semiconductor industry caution against overinterpreting the fire at this stage as a problem stemming from production expansion or a defect across the entire safety management system. The analysis is that it is likely a technical issue in a specific process area.
A semiconductor industry expert who requested anonymity said, "It is reasonable to view this accident as a technical problem that occurred in a specific gas mixing process," adding, "Given that the company has taken steps to prevent recurrence and formed an internal response team, the priority is to identify the specific technical cause in the equipment or process."
By contrast, the fire and safety fields are focusing on the fact that similar accidents recurred in the same process. Jaejin-su, a professor in the Department of Fire and Disaster Prevention at Soongsil Cyber University, said, "The fact that a fire occurred again in the same process suggests that the cause of the initial accident was not completely eliminated, or that unidentified risk factors may remain." He added, "If work resumed after concluding the cause was removed and yet similar accidents recurred, there is a need to reexamine the process as a whole."
The spate of accidents is also heightening concerns in the local community and labor circles. At the Cheongju business sites, chemical exposure and leaks, equipment abnormalities, and fires have occurred repeatedly since the start of the year. The Korean Confederation of Trade Unions (KCTU) Chungbuk chapter recently issued a statement, saying, "Despite the repeated accidents, the cause analysis, measures to prevent recurrence, and the details of supervision and oversight are not being sufficiently disclosed," urging a thorough cause investigation and safety inspection.
The M15 and M15X, where recent accidents occurred, are core production facilities in which SK hynix is investing to expand next-generation DRAM capacity, including high bandwidth memory (HBM). The company said there were no production disruptions due to the fire and that the plant is currently operating normally. An SK hynix official said, "For now, forensics and an investigation into the cause of the fire are underway," adding, "We have nothing further to disclose until the investigation results are available."