The boiler tower collapse at the Ulsan Thermal Power Plant in November of last year, which claimed the lives of seven workers, has been investigated as being directly caused by excessively cutting columns prior to demolition by blasting.

The Ministry of Land, Infrastructure and Transport's Accident Investigation Committee announced today (October 30) that poor structural reviews and a lack of management and oversight led to the accident.

In reality, the column thickness was 15 millimeters, but it was calculated as 24 millimeters, and the weight of the structure was also calculated to be about 520 tons less than the actual weight.

As a result, the columns were unable to withstand the upper weight and buckled, causing the entire structure to collapse.

To prevent recurrence, the investigation committee proposed establishing safety standards for demolition work and strengthening design and construction management.