A blast at an explosives factory on Friday left one person dead and another 12 missing in Tangshan, according to an online announcement by the Hebei provincial government.

Nearby residents said the blast produced a tremendous noise, and they saw mushroom cloud afterward, a report by Chinese National Radio said.

The blast happened as 13 people were producing emulsive explosives in a workshop of the chemical factory, a branch of Kailuan Group, located in Guye district of Tangshan. The city is rich in mineral resources and a hub for steel and iron production in northern China.

The explosives produced at the factory are used for mine exploration.

The official micro blog of the Information Office of Hebei government confirmed the explosion and said that rescue efforts were under way for the missing workers as of 4 pm on Friday.