Rescuers now are trying to remove all the 700 tons of sodium cyanide, which is reported to be stored in the warehouse where the blasts happened in Tianjin. 15% hydrogen peroxide had been prepared, according to The Beijing News. 
These 700 tons of deadly toxics are stored in wooden boxes or iron barrels, 50 kilograms per unit, in the containers.
Sodium cyanide has now been detected in the sewage and leakage has been confirmed, according to The Beijing News. 
According to fire-fighting headquarters, nitric acid items such as potassium nitrate, sodium cyanide are found to be contained in the warehouse that caused the blast. These solid oxidizers are easy to explode if heated or collided. A huge crater has been created on the spot.
http://en.people.cn/n/2015/0813/c90882-8935728.html