Investigation on Deaths in the Confined Spaces at Srisutus Sewage Pump Station during the Maintenance Period, Phuket Province, Thailand, 26th March 2014

Abstract

In the morning of 26^th March 2014, the Occupational Medicine Department in Vachira Phuket Hospital and Phuket Provincial Health Office were called for an emergency of an accident at Srisutus sewage pump station. At the scene, we found 4 people died in the sewage junction hole and a man from Kusorn-thama was unconscious. The Occupational Medicine Department and a rapid response team from the Office of Disease Prevention and Control region 11, Nakorn Sri Thamarat were jointly conducted an investigation on the deaths during 26-27 March 2014. The investigation was to find the cause of the deaths by measuring the environment pollution and interviewing the persons who were in the area of accident.
Before the accident occurred at the sewage junction hole which had diameter of 0.80 m and 4.60 m in depth, maintenance workers opened the metal lid cover for air ventilation during the pump was being repaired. Meanwhile, a waste water leakage on the side wall was releasing sulfa dioxide at the bottom of the pipe and diffusing into the air. Consequently, the maintenance workers inhaled the hazardous air, fall down and became unconscious. The investigation found that level of sulfur dioxide at the accident area was 41.2 ppm which was over the standard TLV-TWA level of 10 ppm** while the level of oxygen was 20.9 percent, carbon monoxide 4 ppm and methane 161 ppm. The level of other gases did not exceed the standard tolerance. Therefore, we concluded that health education for maintenance workers and sub-contractors should be conducted in order to prevent accident and death in confined spaces and hazardous areas.