Hundreds of residents around a polysilicon plant here were evacuated to safety after hydrochloric acid was found to have been leaked, police said Saturday.

The leak occurred at around 11 a.m. from a 200-ton tank of the Woongjin Polysilicon plant located in this city, some 270 kilometers southeast of Seoul, according to police.

Police said that when the accident happened, some workers were staying inside the plant, but no injuries have been reported.

It is yet to be known how much acid leaked from the tank. Police suspect that a frozen valve was ruptured due to the cold weather, letting out the hazardous material.

The exact cause is still under investigation.   

The accident zone was cordoned off and as a precaution, the regional government evacuated about 760 residents to a school located in a safe area, police said. (Yonhap News)