Death Toll from China's Tianjin Warehouse Blasts Rises to 50

The death toll from huge warehouse explosions in the Chinese port city of Tianjin has increased to 50 by Thursday evening, including 17 firemen, Xinhua news agency reported.

About 700 people were admitted to hospital with injuries of various degrees. Seventy of them are in critical condition, Xinhua said, citing reports of local authorities.

The Tianjin Port Group Co. said dozens of its employees were unaccounted for and a search operation is under way. 

Meanwhile, over 200 military specialists in nuclear and biochemical materials were sent to test the air for toxic substances.

The cause of the massive blasts on Wednesday night remains unknown.

According to reports, the warehouse that exploded is owned by a company which transports and stores toxic chemicals including sodium cyanide and toluene diisocyanate, the BBC said. Sodium cyanide is a solid oxidizer that is sensitive to heat and shocks. Toluene diisocyanate reacts with strong oxidizers.

The first explosion was huge, and the second was even more powerful -- the equivalent of 21 metric tons of TNT or a magnitude-2.9 earthquake, according to the China Earthquake Networks Center, the CNN said.