The Office for Government Policy Coordination has requested a prosecutorial investigation into 36 officials of the police, fire agency, municipal governments and the national construction agency in relation to the Cheongju underpass flooding.

Announcing the outcome of its inspection on Friday, the office said the disaster was caused by the unauthorized removal of an embankment along the nearby Miho River, insufficient temporary banks and a failure to monitor and inspect the process.

Despite multiple emergency calls raising concerns about a possible overflow of the river amid heavy rain and flood warnings, agencies tasked with managing the underpass and the river failed to actively endeavor to prevent the tragedy.

The office said the river's water level met the requirement for traffic control at the underpass around 70 minutes before it began to overflow.

The office separately ordered disciplinary action, including a removal from their post, against 63 officials from five public institutions with direct responsibility over command and supervision.

The government is set to revamp the national response system to disasters, such as a reinforcement of governance through a task force, the tightening of underpass restrictions to prevent fatalities, and an expansion of river and stream maintenance.

The Osong underpass flooding, which occurred after some six tons of water from the Miho River inundated the underpass following the collapse of banks from days of heavy rainfall, killed 14 people and injured ten others.