A fire in a gas room at SK Hynix’s Cheongju plant in South Korea triggered a leak of hydrofluoric acid, a highly toxic chemical used in semiconductor etching, forcing the evacuation of approximately 3,600 workers and hospitalizing seven. The incident, which occurred on June 1 at 10:32 AM local time, has raised urgent questions about safety protocols at one of the world’s most critical memory production hubs, even as the company insists there will be no disruption to output.
Fire Suppressed Instantly, But Toxic Gas Continues to Threaten
The emergency unfolded on the sixth-floor gas room connecting the M15 and M15X fabrication facilities at SK Hynix’s Cheongju Fourth Campus. This area houses the piping and storage equipment for the hydrofluoric acid (also known as hydrogen fluoride) essential to the company’s etching and cleaning processes. A fire broke out in this zone, but was immediately extinguished by the plant’s automatic sprinkler system. However, the suppression process itself caused the hydrofluoric acid to leak into the room.
At the time of the incident, ten workers were present. Five reported eye inflammation, a common symptom of exposure to the corrosive gas. Two others, while not exhibiting any immediate symptoms, were hospitalized as a precaution. In total, seven employees are receiving treatment. South Korean fire authorities have stated that the number of casualties could rise as further medical evaluations are conducted.
Following standard emergency procedures, SK Hynix ordered the complete evacuation of both the M15 and M15X factories, displacing around 3,600 employees. Firefighting personnel deployed 34 responders and 12 pieces of equipment to the scene to investigate the leak pathway and assess the full extent of the damage.
Why Hydrofluoric Acid is a High-Risk Chemical in Semiconductor Manufacturing
Hydrofluoric acid is indispensable for semiconductor production, used primarily to etch silicon wafers and clean manufacturing equipment. Its ability to dissolve silicon dioxide makes it a powerful and necessary tool. However, its extreme toxicity is a constant operational hazard. Skin contact can lead to deep, penetrating burns that are slow to heal, and inhalation can cause pulmonary edema, a life-threatening condition where fluid fills the lungs.
The fact that all hospitalized workers reported eye inflammation aligns perfectly with the known effects of hydrogen fluoride exposure. The precise concentration of the leak has not been publicly disclosed, but the synchronized symptoms among the affected workers indicate a significant exposure level. This incident underscores the daily risk that semiconductor workers face, even with stringent safety measures in place.
Is Production Really Unaffected? The Heavy Weight of a ‘No Impact’ Statement
SK Hynix has moved quickly to contain the potential fallout, with a company representative stating that equipment operation is normal and that there will be no production disruptions. The firm plans to allow employees to return to the facilities after completing safety inspections and air quality tests.
For those familiar with the industry, the declaration of “no production impact” invites a degree of skepticism. In September 2013, SK Hynix suffered a massive explosion and fire at its Wuxi, China, plant. At the time, the company also issued reassurances that it would resume operations quickly. Reality proved quite different: full restoration took months. The accident knocked out approximately 13% of the global DRAM supply, causing spot prices to surge by 36% in a matter of days. The supply crunch was so severe that it forced major clients, including NVIDIA and AMD, to scramble for alternative allocation, creating a ripple effect across the entire tech industry.
This week’s incident at Cheongju is different in scale and nature. Unlike the Wuxi catastrophe, which involved a massive explosion that contaminated cleanrooms, the Cheongju fire was contained within a gas room and extinguished immediately. There are no reported damages to the cleanrooms or core manufacturing equipment. The central question now is not whether the plant is damaged, but how long the environmental cleanup and precision inspection will take. One industry insider noted that in past gas leak incidents at semiconductor fabs, the post-event inspection and equipment recalibration processes took far longer than initially anticipated.
A Global Memory Shortage Makes This Incident Especially Critical
The timing of this accident could not be worse for a market already stretched to its limits. The memory industry in 2026 is characterized by an acute supply deficit, driven overwhelmingly by AI data center demand. DRAM contract prices surged by 90 to 95% in the first quarter of 2026 compared to the previous quarter, and a further increase of 58 to 63% is projected for Q2. Inventories among DRAM manufacturers are at critically low levels. Nearly all incremental production is being absorbed by cloud hyperscalers, leaving the PC and mobile segments facing severe allocation pressure.
The Cheongju Fourth Campus is at the very center of this supply chain. The M15 fab, completed in 2018, is one of the world’s largest semiconductor manufacturing facilities and has been a primary source for high-value DRAM. The adjacent M15X facility, originally begun in 2022, was expanded and redefined in 2024 as a dedicated HBM production hub. Equipment installation is in its final stages, with mass production of next-generation memory, including 1b DRAM for HBM3E, slated to begin in 2026.
Any delay, even for a few days, at this strategic node would be immediately felt across the global memory supply network. Financial analysts have already flagged the incident as a potential psychological catalyst for further spot price increases. The market is so tightly balanced that a temporary work stoppage for safety checks, even one unrelated to core equipment, can exacerbate an already inflationary pricing environment.
Why Did This Happen Again? Recurring Safety Concerns at a Critical Plant
This is not SK Hynix’s first hydrofluoric acid accident. In April 2021, a leak at the company’s M16 fab in Icheon injured three workers during equipment inspection. While the current incident appears to involve different circumstances, the recurrence of a toxic gas leak at a major facility demands a closer look at the company’s safety management system.
In semiconductor manufacturing, handling hazardous materials like hydrofluoric acid is an unavoidable necessity. Safety management, therefore, cannot be treated as a separate operational concern; it is an integral component of manufacturing capability. When similar incidents recur at a company of SK Hynix’s caliber, it indicates a systemic issue that extends beyond an individual error.
For now, the seven injured workers are reportedly not in life-threatening condition. The plant is expected to resume normal operations after completing inspections. But this accident serves as a stark reminder of a fragile reality: the world’s supply of advanced memory chips depends on a handful of ultra-complex, geographically concentrated facilities that operate in constant proximity to extreme chemical hazards. The market’s reaction in the coming days will reveal not just the health of the plant, but the depth of the underlying fragility in the global semiconductor supply chain.
