As of 11:30 PM Monday, the chemical plant blast in north China's port city of Tianjin rose to seven with another one still missing, said rescuers.

At least three others were injured in the blast and have already been hospitalized.

The blast took place at about 3:00 PM at the workshop of the Yikun (Tianjin) Refined Chemical Industry Science and Technology Co. Ltd., which is located at the Xinda Industrial Park of Jinnan District in southern Tianjin.

The blast caused the rupture of an ammonia pipeline, which is now being repaired. However, there is no leak of ammonia in large amount, according to the fire-fighters at the scene.

Ammonia is a colorless and pungent gas, which is widely used in the production of fertilizer and a variety of nitrogen-containing organic and inorganic chemicals.

The workshop has been leveled and the blast-triggered fire has been quenched. Workers at the Xinda Industrial Park have been evacuated.

Upon receiving the report, Tianjin Mayor Dai Xianglong and other local officials rushed to the scene to organize rescue operation.

Yikun, originally the Tianjin Perfume Factory founded in 1985, is a producer of fragrance for making cosmetics, soap, detergent, face cream, fixative and perfume.

The cause of the blast is being investigated.

(Xinhua News Agency August 8, 2006)