Abstract

A spill of silicon tetrachloride (SiCl4) and trichlorosilane (HSiCl3) occurred on a high-purity polysilicon production line of a solar panel manufacturing plant located in the rural area of Gunsan City, Korea at 4:03 p.m. on the afternoon of June 22, 2015. SiCl4 or HSiCl3 readily reacts with water to form a irritant hydrogen chloride (HCl) vapour. Surveys of the health effects from these aerosols were conducted from 111 subjects (including 1 worker and 110 rural settlers), who had been exposed to the vapour and mist. Most of the affected patients suffered irritation in the eyes, skin, and upper airways. The symptoms of headache (49.5%) and dizziness (43.2%) were also observed in many of these aerosol-exposed subjects. Thirty-nine subjects (35.1%) still suffered from residual symptoms, 6 months after follow-up observations. Two of these subjects underwent neuropsychiatric treatment due to post-traumatic stress symptoms and adjustment disorder (1.8%). The toxic effects of SiCl4 and SiCl3H are reportedly due to the hydrochloric acid (water-soluble toxic aerosol) released in the process of hydrolysis. Irritation of the mucous membranes is the primary pathophysiologic mechanism of the toxic reaction. This study showed that many subjects exposed to toxic vapours of silanes and chlorinated derivatives experienced central nervous system (CNS) symptoms, such as headache and/or dizziness. Furthermore, neuropsychiatric therapy may be implemented for subjects accidentally exposed to toxic chemicals through early screening and intervention.