The Nuclear Safety and Security Commission (NSSC) unveiled the interim results of its investigation into the incident during a session of the parliamentary science and technology committee.
The incident occurred on May 27 at Samsung's Giheung campus in Yongin, south of Seoul. The two workers were operating an X-ray inspection machine on a chip production line when their hands were accidentally exposed to radiation. They underwent examinations after exhibiting symptoms such as swollen fingers and red spots on their hands.
The NSSC investigation found that the workers received equivalent doses of 94 and 28 millisieverts (mSv) to their hands, far exceeding the annual limit of 0.5 mSv, it told lawmakers. One worker received a whole-body effective dose of 130 mSv, surpassing the yearly threshold of 50 mSv.
While blood and chromosome tests showed normal results, the affected employees are under observation for symptoms including swelling, redness and skin peeling on their hands.
Following the incident, the NSSC ordered the suspension of the faulty equipment and maintenance activities on similar devices at the facility. An investigation into the cause of the incident, including a potential wiring error in the safety interlock system, is underway.
The event has rekindled concerns about workplace safety at Samsung's facilities. In 2018, the company acknowledged past safety lapses and apologized for illnesses and deaths among workers at its chip and display plants.
The NSSC plans to conduct a special inspection of Samsung's radiation safety management practices until late September and will release the final investigation results, including preventive measures, at that time.