Two workers at SK Hynix's Campus 4 in Cheongju were hospitalized Wednesday after coming into contact with a toxic chemical while moving equipment.
The incident occurred at around 3:58 p.m. Wednesday, when the two workers came into contact with a liquid believed to be tetramethylammonium hydroxide, or TMAH, according to industry sources.
The workers showed no unusual symptoms after the exposure but were taken to a hospital as a precaution.
TMAH is a strongly alkaline chemical widely used in semiconductor and display manufacturing to clean and develop silicon wafers. It is classified as a toxic substance capable of causing death through skin contact alone.
Police are investigating the incident, including the possibility that TMAH residue mixed with water and dripped from equipment that had been washed.
The Cheongju facility has seen a string of accidents in recent months.
On June 1, a fire broke out in a sixth-floor gas room connecting the M15 and M15X factories at Campus 4, causing a small amount of fluorine to leak.
On May 27, sparks flew from semiconductor processing equipment inside the M11 factory, prompting workers to evacuate for about an hour. On Jan. 19, five workers performing pipe work at the factory were exposed to phosphoric acid that dripped from overhead piping.
klee@heraldcorp.com
