Deputy permanent secretary Nisakorn Jungjaroentham said on Saturday that officers from the Water Technology and Industrial Pollution Management Bureau and the Department of Industrial Works had investigated the cause of accident.

Five people, including a female university student and four employees, were killed on Friday in an accident in the wastewater sewer system at CPF in Bang Na district.

A press conference on the accident by the Department of Industrial Works was scheduled for Monday, she added.

Meanwhile, Labour Minister General Sirichai Distakul ordered the Department of Labor Protection and Welfare to immediately provide assistance to the victims.

He has also urged the Social Security Office to make sure that CPF employees were eligible for its protections and are compensated by the Social Security Fund.