12 missing in north China factory blast

Photo taken on March 7, 2014 shows the blast site at a chemical plant in north China's Tangshan city, Hebei province. One person was injured and another 12 are missing after the factory blast on Friday. (Xinhua/Li Junyi)

One person was injured and another 12 are missing after a factory blast in north China's Tangshan, Hebei province Friday.

The blast took place at 11:25 a.m. in a chemical plant in Tangshan City. The plant mainly produces water-proof explosives for mining.

An initial investigation showed that 13 people were working inside the factory at the time of the blast.

Rescue work continues.